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Sample records for large telescope adaptive

  1. Adaptive Optics for Large Telescopes

    SciTech Connect

    Olivier, S

    2008-06-27

    The use of adaptive optics was originally conceived by astronomers seeking to correct the blurring of images made with large telescopes due to the effects of atmospheric turbulence. The basic idea is to use a device, a wave front corrector, to adjust the phase of light passing through an optical system, based on some measurement of the spatial variation of the phase transverse to the light propagation direction, using a wave front sensor. Although the original concept was intended for application to astronomical imaging, the technique can be more generally applied. For instance, adaptive optics systems have been used for several decades to correct for aberrations in high-power laser systems. At Lawrence Livermore National Laboratory (LLNL), the world's largest laser system, the National Ignition Facility, uses adaptive optics to correct for aberrations in each of the 192 beams, all of which must be precisely focused on a millimeter scale target in order to perform nuclear physics experiments.

  2. Adaptive optics operations at the Large Binocular Telescope Observatory

    NASA Astrophysics Data System (ADS)

    Miller, Douglas L.; Taylor, Gregory; Christou, Julian C.; Zhang, Xianyu; Brusa Zappellini, Guido; Rahmer, Gustavo; Lefebvre, Michael; Puglisi, Alfio; Pinna, Enrico; Esposito, Simone

    2016-07-01

    The goal for the adaptive optics systems at the Large Binocular Telescope Observatory (LBTO) is for them to operate fully automatically, without the need for an AO Scientist, and to be run by the observers and/or the telescope operator. This has been built into their design. Initially, the AO systems would close the loop using optimal parameters based on the observing conditions and guide star brightness, without adapting to changing conditions. We present the current status of AO operations as well as recent updates that improve the operational efficiency and minimize downtime. Onsky efficiency and performance will also be presented, along with calibrations required for AO closed loop operation.

  3. Scaling multiconjugate adaptive optics performance estimates to extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Ellerbroek, Brent L.; Rigaut, Francois J.

    2000-07-01

    Multi-conjugate adaptive optics (MCAO) is a key technology for extremely large, ground-based telescopes (ELT's) because it enables near-uniform atmospheric turbulence compensation over fields-of-view considerably larger than can be corrected with more conventional AO systems. Quantitative performance evaluation using detailed analytical or simulation models is difficult, however, due to the very large number of deformable mirror (DM) actuators, wave front sensors (WFS) subapertures, and guide stars which might comprise an MCAO system for an ELT. This paper employs more restricted minimal variance estimation methods to evaluate the fundamental performance limits imposed by anisoplanatism alone upon MCAO performance for a range of sample cases. Each case is defined by a atmospheric turbulence profile, telescope aperture diameter, field-of-view, guide star constellation, and set of DM conjugate ranges. For a Kolmogorov turbulence spectrum with an infinite outer scale, MCAO performance for a whole range of aperture diameters and proportional fields-of-view can be computed at once using a scaling law analogous to the (D/dO)5/3 formula for the cone effect. For 30 meter telescopes, useful levels of performance are possible across a 1.0 - 2.0 arc minute square field-of-view using 5 laser guide stars (LGS's) and 3 DM's, and somewhat larger fields can be corrected using 9 guide stars and 4 mirrors. 3 or more tip/tilt natural guide stars (NGS's) are necessary to detect modes of tilt anisoplanatism which cannot be detected using LGS's, however. LGS MCAO performance is a quite weak function of aperture diameter for a fixed field-of-view, and it is tempting to scale these results to larger apertures. NGS MCAO performance is moderately superior to LGS MCAO if the NGS constellation is within the compensated field-of-view, but degrades rapidly as the guide stars move away from the field. The penalty relaxes slowly with increasing aperture diameter, but how to extrapolate this trend

  4. Optical Design for Extremely Large Telescope Adaptive Optics Systems

    SciTech Connect

    Bauman, Brian J.

    2003-01-01

    Designing an adaptive optics (AO) system for extremely large telescopes (ELT's) will present new optical engineering challenges. Several of these challenges are addressed in this work, including first-order design of multi-conjugate adaptive optics (MCAO) systems, pyramid wavefront sensors (PWFS's), and laser guide star (LGS) spot elongation. MCAO systems need to be designed in consideration of various constraints, including deformable mirror size and correction height. The y,{bar y} method of first-order optical design is a graphical technique that uses a plot with marginal and chief ray heights as coordinates; the optical system is represented as a segmented line. This method is shown to be a powerful tool in designing MCAO systems. From these analyses, important conclusions about configurations are derived. PWFS's, which offer an alternative to Shack-Hartmann (SH) wavefront sensors (WFS's), are envisioned as the workhorse of layer-oriented adaptive optics. Current approaches use a 4-faceted glass pyramid to create a WFS analogous to a quad-cell SH WFS. PWFS's and SH WFS's are compared and some newly-considered similarities and PWFS advantages are presented. Techniques to extend PWFS's are offered: First, PWFS's can be extended to more pixels in the image by tiling pyramids contiguously. Second, pyramids, which are difficult to manufacture, can be replaced by less expensive lenslet arrays. An approach is outlined to convert existing SH WFS's to PWFS's for easy evaluation of PWFS's. Also, a demonstration of PWFS's in sensing varying amounts of an aberration is presented. For ELT's, the finite altitude and finite thickness of LGS's means that the LGS will appear elongated from the viewpoint of subapertures not directly under the telescope. Two techniques for dealing with LGS spot elongation in SH WFS's are presented. One method assumes that the laser will be pulsed and uses a segmented micro-electromechanical system (MEMS) to track the LGS light subaperture by

  5. Development of laser guide stars and adaptive optics for large astronomical telescopes

    SciTech Connect

    Max, C.E.; Avicola, K.; Bissinger, H.; Brase, J.M.; Gavel, D.T.; Friedman, H.; Morris, J.R.; Olivier, S.S.; Rapp, D.; Salmon, J.T.; Waltjen, K.

    1992-06-29

    We describe a feasibility experiment to demonstrate high-order adaptive optics using a sodium-layer laser guide star. We use the copper-vapor-pumped dye lasers developed for LLNL`s atomic Vapor Laser Isotope Separation program to create the laser guide star. Closed-loop adaptive corrections will be accomplished using a 69-subaperture adaptive optics system on a one-meter telescope at LLNL. The laser bream is projected upwards from a beam director approximately 5 meters away from the main telescope, and is expected to form a spot 1-2 meters in diameter at the atmospheric sodium layer (95 km altitude). We describe the overall system architecture and adaptive optics components, and analyze the expected performance. Our long-term goal is to develop sodium-layer laser guide stars and adaptive optics for large astronomical telescopes. We discuss preliminary design trade-offs for the Keck Telescope at Mauna Kea.

  6. Development of laser guide stars and adaptive optics for large astronomical telescopes

    SciTech Connect

    Max, C.E.; Avicola, K.; Bissinger, H.; Brase, J.M.; Gavel, D.T.; Friedman, H.; Morris, J.R.; Olivier, S.S.; Rapp, D.; Salmon, J.T.; Waltjen, K.

    1992-06-29

    We describe a feasibility experiment to demonstrate high-order adaptive optics using a sodium-layer laser guide star. We use the copper-vapor-pumped dye lasers developed for LLNL's atomic Vapor Laser Isotope Separation program to create the laser guide star. Closed-loop adaptive corrections will be accomplished using a 69-subaperture adaptive optics system on a one-meter telescope at LLNL. The laser bream is projected upwards from a beam director approximately 5 meters away from the main telescope, and is expected to form a spot 1-2 meters in diameter at the atmospheric sodium layer (95 km altitude). We describe the overall system architecture and adaptive optics components, and analyze the expected performance. Our long-term goal is to develop sodium-layer laser guide stars and adaptive optics for large astronomical telescopes. We discuss preliminary design trade-offs for the Keck Telescope at Mauna Kea.

  7. GSMT Education: Teaching about Adaptive Optics and Site Selection Using Extremely Large Telescopes

    NASA Astrophysics Data System (ADS)

    Sparks, R. T.; Pompea, S. M.

    2010-08-01

    Giant Segmented Mirror Telescopes (GSMT) represents the next generation of extremely large telescopes (ELT). Currently there are three active ELT projects, all established as international partnerships to build telescopes of greater than 20 meters aperture. Two of these have major participation by U.S. institutions: the Giant Magellan Telescope and the Thirty Meter Telescope. The ESO-ELT is under development by the European Southern Observatory and other European institutions. We have developed educational activities to accompany the design phase of these projects. The current activities focus on challenges faced in the design and site selection of a large telescope. The first module is on site selection. This online module is based on the successful Astronomy Village program model. Students evaluate several potential sites to decide where to build the GSMT. They must consider factors such as weather, light pollution, seeing, logistics, and geography. The second project has developed adaptive optics teaching units suitable for high school.

  8. Adaptive optics capabilities at the Large Binocular Telescope Observatory

    NASA Astrophysics Data System (ADS)

    Christou, J. C.; Brusa, G.; Conrad, A.; Esposito, S.; Herbst, T.; Hinz, P.; Hill, J. M.; Miller, D. L.; Rabien, S.; Rahmer, G.; Taylor, G. E.; Veillet, C.; Zhang, X.

    2016-07-01

    We present an overview of the current and future adaptive optics systems at the LBTO along with the current and planned science instruments they feed. All the AO systems make use of the two 672 actuator adaptive secondary mirrors. They are (1) FLAO (NGS/SCAO) feeding the LUCI NIR imagers/spectrographs; (2) LBTI/AO (NGS/SCAO) feeding the NIR/MIR imagers and LBTI beam combiner; (3) the ARGOS LGS GLAO system feeding LUCIs; and (4) LINC-NIRVANA - an NGS/MCAO imager and interferometer system. AO performance of the current systems is presented along with proposed performances for the newer systems taking into account the future instrumentation.

  9. The large binocular telescope.

    PubMed

    Hill, John M

    2010-06-01

    The Large Binocular Telescope (LBT) Observatory is a collaboration among institutions in Arizona, Germany, Italy, Indiana, Minnesota, Ohio, and Virginia. The telescope on Mount Graham in Southeastern Arizona uses two 8.4 m diameter primary mirrors mounted side by side. A unique feature of the LBT is that the light from the two Gregorian telescope sides can be combined to produce phased-array imaging of an extended field. This cophased imaging along with adaptive optics gives the telescope the diffraction-limited resolution of a 22.65 m aperture and a collecting area equivalent to an 11.8 m circular aperture. This paper describes the design, construction, and commissioning of this unique telescope. We report some sample astronomical results with the prime focus cameras. We comment on some of the technical challenges and solutions. The telescope uses two F/15 adaptive secondaries to correct atmospheric turbulence. The first of these adaptive mirrors has completed final system testing in Firenze, Italy, and is planned to be at the telescope by Spring 2010.

  10. Monte Carlo modelling of multiconjugate adaptive optics performance on the European Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Basden, A. G.

    2015-11-01

    The performance of a wide-field adaptive optics system depends on input design parameters. Here we investigate the performance of a multiconjugate adaptive optics system design for the European Extremely Large Telescope, using an end-to-end Monte Carlo adaptive optics simulation tool, DASP (Durham adaptive optics simulation platform). We consider parameters such as the number of laser guide stars, sodium layer depth, wavefront sensor pixel scale, number of deformable mirrors (DMs), mirror conjugation and actuator pitch. We provide potential areas where costs savings can be made, and investigate trade-offs between performance and cost. We conclude that a six-laser guide star system using three DMs seems to be a sweet spot for performance and cost compromise.

  11. A FOSSIL BULGE GLOBULAR CLUSTER REVEALED BY VERY LARGE TELESCOPE MULTI-CONJUGATE ADAPTIVE OPTICS

    SciTech Connect

    Ortolani, Sergio; Barbuy, Beatriz; Momany, Yazan; Saviane, Ivo; Jilkova, Lucie; Bica, Eduardo; Salerno, Gustavo M.; Jungwiert, Bruno E-mail: barbuy@astro.iag.usp.br E-mail: isaviane@eso.org E-mail: bica@if.ufrgs.br

    2011-08-10

    The globular cluster HP 1 is projected on the bulge, very close to the Galactic center. The Multi-Conjugate Adaptive Optics Demonstrator on the Very Large Telescope allowed us to acquire high-resolution deep images that, combined with first epoch New Technology Telescope data, enabled us to derive accurate proper motions. The cluster and bulge fields' stellar contents were disentangled through this process and produced an unprecedented definition in color-magnitude diagrams of this cluster. The metallicity of [Fe/H] {approx} -1.0 from previous spectroscopic analysis is confirmed, which together with an extended blue horizontal branch imply an age older than the halo average. Orbit reconstruction results suggest that HP 1 is spatially confined within the bulge.

  12. Sensitivity to differential piston and to adaptive optics errors with the Large Binocular Telescope Interferometer

    NASA Astrophysics Data System (ADS)

    Patru, Fabien; Esposito, Simone; Puglisi, Alfio; Riccardi, Armando; Pinna, Enrico; Arcidiacono, Carmelo; Hill, John; Hinz, Philip

    2016-08-01

    On-sky adaptive optics wavefront screens have been used and random optical path fluctuations - differential pistons - have been included in numerical simulations for the Large Binocular Telescope Interferometer. We characterize the Point Spread Function (PSF) and the Optical Transfer Function (OTF) by computing respectively the interferometric Strehl and the visibility criteria. We study the contribution of the wavefront disturbance induced by each adaptive optics system and by the optical path difference between the arms of the LBTI. To provide an image of quality (Strehl above 70%) suitable with standard science cases , the requirements for a LBTI mode in the visible wavelengths (750nm) must be at least an adaptive optics wavefront RMS fluctuations below λ/18≍40nm (Strehl above 90%) provided by each adaptive optics system, and a differential piston RMS fluctuations below λ/8≍100nm in the overall LBTI system. The adaptive optics wavefront errors - mainly the differential tip-tilt - appear to be more critical than the differential piston.

  13. Large Binocular Telescope Project

    NASA Astrophysics Data System (ADS)

    Hill, John M.

    1997-03-01

    The large binocular telescope (LBT) project have evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 by 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astrofisico di Arcetri and the Research Corporation based in Tucson, Arizona. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train -- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in the fall of 1996 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximum flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximum stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1996 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson), EIE and ADS Italia

  14. Laser guide star wavefront sensing for ground-layer adaptive optics on extremely large telescopes.

    PubMed

    Clare, Richard M; Le Louarn, Miska; Béchet, Clementine

    2011-02-01

    We propose ground-layer adaptive optics (GLAO) to improve the seeing on the 42 m European Extremely Large Telescope. Shack-Hartmann wavefront sensors (WFSs) with laser guide stars (LGSs) will experience significant spot elongation due to off-axis observation. This spot elongation influences the design of the laser launch location, laser power, WFS detector, and centroiding algorithm for LGS GLAO on an extremely large telescope. We show, using end-to-end numerical simulations, that with a noise-weighted matrix-vector-multiply reconstructor, the performance in terms of 50% ensquared energy (EE) of the side and central launch of the lasers is equivalent, the matched filter and weighted center of gravity centroiding algorithms are the most promising, and approximately 10×10 undersampled pixels are optimal. Significant improvement in the 50% EE can be observed with a few tens of photons/subaperture/frame, and no significant gain is seen by adding more than 200 photons/subaperture/frame. The LGS GLAO is not particularly sensitive to the sodium profile present in the mesosphere nor to a short-timescale (less than 100 s) evolution of the sodium profile. The performance of LGS GLAO is, however, sensitive to the atmospheric turbulence profile.

  15. Telescope Adaptive Optics Code

    SciTech Connect

    Phillion, D.

    2005-07-28

    The Telescope AO Code has general adaptive optics capabilities plus specialized models for three telescopes with either adaptive optics or active optics systems. It has the capability to generate either single-layer or distributed Kolmogorov turbulence phase screens using the FFT. Missing low order spatial frequencies are added using the Karhunen-Loeve expansion. The phase structure curve is extremely dose to the theoreUcal. Secondly, it has the capability to simulate an adaptive optics control systems. The default parameters are those of the Keck II adaptive optics system. Thirdly, it has a general wave optics capability to model the science camera halo due to scintillation from atmospheric turbulence and the telescope optics. Although this capability was implemented for the Gemini telescopes, the only default parameter specific to the Gemini telescopes is the primary mirror diameter. Finally, it has a model for the LSST active optics alignment strategy. This last model is highly specific to the LSST

  16. Engineering aspects of the Large Binocular Telescope Observatory adaptive optics systems

    NASA Astrophysics Data System (ADS)

    Brusa, Guido; Ashby, Dave; Christou, Julian C.; Kern, Jonathan; Lefebvre, Michael; McMahon, Tom J.; Miller, Douglas; Rahmer, Gustavo; Sosa, Richard; Taylor, Gregory; Vogel, Conrad; Zhang, Xianyu

    2016-07-01

    Vertical profiles of the atmospheric optical turbulence strength and velocity is of critical importance for simulating, designing, and operating the next generation of instruments for the European Extremely Large Telescope. Many of these instruments are already well into the design phase meaning these profies are required immediately to ensure they are optimised for the unique conditions likely to be observed. Stereo-SCIDAR is a generalised SCIDAR instrument which is used to characterise the profile of the atmospheric optical turbulence strength and wind velocity using triangulation between two optical binary stars. Stereo-SCIDAR has demonstrated the capability to resolve turbulent layers with the required vertical resolution to support wide-field ELT instrument designs. These high resolution atmospheric parameters are critical for design studies and statistical evaluation of on-sky performance under real conditions. Here we report on the new Stereo-SCIDAR instrument installed on one of the Auxillary Telescope ports of the Very Large Telescope array at Cerro Paranal. Paranal is located approximately 20 km from Cerro Armazones, the site of the E-ELT. Although the surface layer of the turbulence will be different for the two sites due to local geography, the high-altitude resolution profiles of the free atmosphere from this instrument will be the most accurate available for the E-ELT site. In addition, these unbiased and independent profiles are also used to further characterise the site of the VLT. This enables instrument performance calibration, optimisation and data analysis of, for example, the ESO Adaptive Optics facility and the Next Generation Transit Survey. It will also be used to validate atmospheric models for turbulence forecasting. We show early results from the commissioning and address future implications of the results.

  17. Telescope performance at the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Hill, John M.; Rothberg, Barry; Christou, Julian C.; Summers, Kellee R.; Summers, Douglas M.

    2016-07-01

    The Large Binocular Telescope Observatory is a collaboration between institutions in Arizona, Germany, Italy, Indiana, Minnesota, Ohio and Virginia. The telescope uses two 8.4-m diameter primary mirrors mounted sideby- side on the same AZ-EL mount to produce a collecting area equivalent to an 11.8-meter aperture. Adaptive optics loops are routinely closed with natural stars on both sides for sided and combined beam observations. Rayleigh laser guide stars provide GLAO seeing improvement. With the telescope now in operation for 10 years, we report on various statistics of telescope performance and seeing-limited image quality. Statistics of telescope performance are reported in the areas of off-axis guiding, open-loop mount tracking, active optics and vibration. Delivered image quality is reported as measured by the DIMM and several guide cameras as a function of other parameters such as temperature and wind velocity. Projects to improve image quality and dome seeing are underway.

  18. Adaptive optics with four laser guide stars: correction of the cone effect in large telescopes.

    PubMed

    Viard, Elise; Le, Louarn Miska; Hubin, Norbert

    2002-01-01

    We study the performance of an adaptive optics (AO) system with four laser guide stars (LGSs) and a natural guide star (NGS). The residual cone effect with four LGSs is obtained by a numerical simulation. This method allows the adaptive optics system to be extended toward the visible part of the spectrum without tomographic reconstruction of three-dimensional atmospheric perturbations, resolving the cone effect in the visible. Diffraction-limited images are obtained with 17-arc ms precision in median atmospheric conditions at wavelengths longer than 600 nm. The gain achievable with such a system operated on an existing AO system is studied. For comparison, performance in terms of achievable Strehl ratio is also computed for a reasonable system composed of a 40 x 40 Shack-Hartmann wave-front sensor optimized for the I band. Typical errors of a NGS wave front are computed by use of analytical formulas. With the NGS errors and the cone effect, the Strehl ratio can reach 0.45 at 1.25 microm under good-seeing conditions with the Nasmyth Adaptive Optics System (NAOS; a 14 x 14 subpupil wave-front sensor) at the Very Large Telescope and 0.8 with a 40 x 40 Shack-Hartmann wave-front sensor.

  19. Monte Carlo modelling of multi-object adaptive optics performance on the European Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Basden, A. G.; Morris, T. J.

    2016-12-01

    The performance of a wide-field adaptive optics (AO) system depends on input design parameters. Here we investigate the performance of a multi-object AO system design for the European Extremely Large Telescope, using an end-to-end Monte Carlo AO simulation tool, Durham adaptive optics simulation platform, with relevance for proposed instruments such as MOSAIC. We consider parameters such as the number of laser guide stars, sodium layer depth, wavefront sensor pixel scale, actuator pitch and natural guide star availability. We provide potential areas where costs savings can be made, and investigate trade-offs between performance and cost, and provide solutions that would enable such an instrument to be built with currently available technology. Our key recommendations include a trade-off for laser guide star wavefront sensor pixel scale of about 0.7 arcsec per pixel, and a field of view of at least 7 arcsec, that electron multiplying CCD technology should be used for natural guide star wavefront sensors even if reduced frame rate is necessary, and that sky coverage can be improved by a slight reduction in natural guide star sub-aperture count without significantly affecting tomographic performance. We find that AO correction can be maintained across a wide field of view, up to 7 arcmin in diameter. We also recommend the use of at least four laser guide stars, and include ground-layer and multi-object AO performance estimates.

  20. Numerical simulation studies for the first-light adaptive optics system of the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Carbillet, Marcel; Riccardi, Armando; Esposito, Simone

    2004-10-01

    We present our latest results concerning the simulation studies performed for the first-light adaptive optics (AO) system of the Large Binocular Telescope (LBT), namely WLBT. After a brief description of the "raw" performance evaluation results, in terms of Strehl ratios attained in the various considered bands (from V to K), we focus on the "scientific" performance that will be obtained when considering the subsequent instrumentation that will benefit from the correction given by the AO system WLBT and the adaptive secondary mirrors LBT 672. In particular, we discuss the performance of the coupling with the instrument LUCIFER, working at near-infrared bands, in terms of signal-to-noise values and limiting magnitudes, and in both the cases of spectroscopy and photometric detection. We also give the encircled energies that are expected in the visible bands, result relevant in one hand for the instrument PEPSI, and in other hand for the "technical viewer" that will be on board the WLBT system itself.

  1. The field stabilization and adaptive optics mirrors for the European Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Vernet, Elise; Jochum, Lieselotte; La Penna, Paolo; Hubin, Norbert; Muradore, Riccardo; Casalta, Joan Manel; Kjelberg, Ivar; Sinquin, Jean-Christophe; Locre, Frédéric; Morin, Pierre; Cousty, Raphaël; Lurçon, Jean-Marie; Roland, Jean-Jacques; Crepy, Bruno; Gabriel, Eric; Biasi, Roberto; Andrighettoni, Mario; Angerer, Gerald; Gallieni, Daniele; Mantegazza, Marco; Tintori, Matteo; Molinari, Emilio; Tresoldi, Daniela; Toso, Giorgio; Spanó, Paolo; Riva, Marco; Crimi, Giuseppe; Riccardi, Armando; Marque, Gilles; Carel, Jean-Louis; Ruch, Eric

    2008-07-01

    A 42 meters telescope does require adaptive optics to provide few milli arcseconds resolution images. In the current design of the E-ELT, M4 provides adaptive correction while M5 is the field stabilization mirror. Both mirrors have an essential role in the E-ELT telescope strategy since they do not only correct for atmospheric turbulence but have also to cancel part of telescope wind shaking and static aberrations. Both mirrors specifications have been defined to avoid requesting over constrained requirements in term of stroke, speed and guide stars magnitude. Technical specifications and technological issues are discussed in this article. Critical aspects and roadmap to assess the feasibility of such mirrors are outlined.

  2. DM/LCWFC based adaptive optics system for large aperture telescopes imaging from visible to infrared waveband.

    PubMed

    Sun, Fei; Cao, Zhaoliang; Wang, Yukun; Zhang, Caihua; Zhang, Xingyun; Liu, Yong; Mu, Quanquan; Xuan, Li

    2016-11-28

    Almost all the deformable mirror (DM) based adaptive optics systems (AOSs) used on large aperture telescopes work at the infrared waveband due to the limitation of the number of actuators. To extend the imaging waveband to the visible, we propose a DM and Liquid crystal wavefront corrector (DM/LCWFC) combination AOS. The LCWFC is used to correct the high frequency aberration corresponding to the visible waveband and the aberrations of the infrared are corrected by the DM. The calculated results show that, to a 10 m telescope, DM/LCWFC AOS which contains a 1538 actuators DM and a 404 × 404 pixels LCWFC is equivalent to a DM based AOS with 4057 actuators. It indicates that the DM/LCWFC AOS is possible to work from visible to infrared for larger aperture telescopes. The simulations and laboratory experiment are performed for a 2 m telescope. The experimental results show that, after correction, near diffraction limited resolution USAF target images are obtained at the wavebands of 0.7-0.9 μm, 0.9-1.5 μm and 1.5-1.7 μm respectively. Therefore, the DM/LCWFC AOS may be used to extend imaging waveband of larger aperture telescope to the visible. It is very appropriate for the observation of spatial objects and the scientific research in astronomy.

  3. Novel Adaptive Optics concepts : wavefront sensing with sodium laser guide stars at Extemely Large Telescopes and simultaneous differential imaging

    NASA Astrophysics Data System (ADS)

    Kellner, Stephan Albert

    2005-12-01

    Since more than 15 years, Adaptive Optics (AO) is a proven concept to reach diffraction limited imaging at modern astronomical telescopes. In the case of next generation telescopes (Extremely Large Telescopes (ELTs)) with aperture diameters of up to 100m, sodium laser guide star based multi-conjugated-AO systems will be a basic requirement to exploit their full capability in terms of resolution and light concentration. A drawback of such an approach emerges in the finite distance and vertical extent of the sodium beacon in the mesosphere with respect to the telescope. This induces effects such as perspective elongation, where conventional wavefront sensing mechanisms will fail. Although several engineering concepts are under development to counteract these constraints at the cost of overall light efficiency and increased system complexity, this thesis proposes a novel kind of wavefront sensing technique to overcome the imposed limitations in a more natural way. The sensing technique is composed of two independently working sensors, a reflective rod and a mask with circular slits, each a representative of a novel wavefront sensor class, the so called z-invariant and Inverse Bessel Beam technique. Both are discussed in this thesis with a focus on the Inverse Bessel Beam technique. The latter is compared to alternative concepts such as temporal gating, with respect to the photon efficiency. Furthermore, the reflective rod was tested for its feasibility in laboratory conditions and in a more realistic environment at the William Herschel Telescope (WHT) at La Palma. With this test run its sensing principle has been verified. A novel technique already intensively used at 8m class telescopes is Simultaneous Differential Imaging. The direct detection of giant extra-solar planets is and will be a major science driver for galactic astronomy in the coming years. Modern telescope facilities such as the VLT reach, by means of adaptive optics, potentially the capability in terms

  4. The Large Binocular Telescope Project

    NASA Astrophysics Data System (ADS)

    Hill, J. M.

    1994-12-01

    The Large Binocular Telescope (LBT) Project has evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 x 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astronomico di Arcetri and the Research Corporation based in Tucson. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train --- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in late fall 1995 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximum flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximum stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1995 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson) and ADS Italia. Construction

  5. The Large Binocular Telescope Project

    NASA Astrophysics Data System (ADS)

    Hill, J. M.

    1995-05-01

    The Large Binocular Telescope (LBT) Project has evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 x 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astrofisico di Arcetri and the Research Corporation based in Tucson. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train --- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in spring of 1996 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximicrons flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximicrons stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1995 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson) and ADS Italia

  6. The Large Area Telescope

    SciTech Connect

    Michelson, Peter F.; /KIPAC, Menlo Park /Stanford U., HEPL

    2007-11-13

    The Large Area Telescope (LAT), one of two instruments on the Gamma-ray Large Area Space Telescope (GLAST) mission, is an imaging, wide field-of-view, high-energy pair-conversion telescope, covering the energy range from {approx}20 MeV to more than 300 GeV. The LAT is being built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. The scientific objectives the LAT will address include resolving the high-energy gamma-ray sky and determining the nature of the unidentified gamma-ray sources and the origin of the apparently isotropic diffuse emission observed by EGRET; understanding the mechanisms of particle acceleration in celestial sources, including active galactic nuclei, pulsars, and supernovae remnants; studying the high-energy behavior of gamma-ray bursts and transients; using high-energy gamma-rays to probe the early universe to z {ge} 6; and probing the nature of dark matter. The components of the LAT include a precision silicon-strip detector tracker and a CsI(Tl) calorimeter, a segmented anticoincidence shield that covers the tracker array, and a programmable trigger and data acquisition system. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large field-of-view and ensuring that nearly all pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. This paper includes a description of each of these LAT subsystems as well as a summary of the overall performance of the telescope.

  7. Very Large Telescope Adaptive Optics Community Days Report on the ESO Workshop

    NASA Astrophysics Data System (ADS)

    Leibundgut, B.; Kasper, M.; Kuntschner, H.

    2016-12-01

    The future of adaptive optics (AO) instruments at the VLT was discussed during a two-day workshop. Three major directions emerged from these discussions: adaptive optics in the optical; multi-object adaptive optics (MOAO); and extreme adaptive optics (XAO). The science cases for these three options were presented and the discussions are summarised. ESO is now planning to provide detailed science cases for an optical AO system and to prepare upgrade plans for XAO and MOAO.

  8. Wavefront Analysis of Adaptive Telescope

    NASA Technical Reports Server (NTRS)

    Hadaway, James B.; Hillman, Lloyd

    1997-01-01

    The motivation for this work came from a NASA Headquarters interest in investigating design concepts for a large space telescope employing active optics technology. The development of telescope optical requirements and potential optical design configurations is reported.

  9. Adaptive-optics performance of Antarctic telescopes.

    PubMed

    Lawrence, Jon S

    2004-02-20

    The performance of natural guide star adaptive-optics systems for telescopes located on the Antarctic plateau is evaluated and compared with adaptive-optics systems operated with the characteristic mid-latitude atmosphere found at Mauna Kea. A 2-m telescope with tip-tilt correction and an 8-m telescope equipped with a high-order adaptive-optics system are considered. Because of the large isoplanatic angle of the South Pole atmosphere, the anisoplanatic error associated with an adaptive-optics correction is negligible, and the achievable resolution is determined only by the fitting error associated with the number of corrected wave-front modes, which depends on the number of actuators on the deformable mirror. The usable field of view of an adaptive-optics equipped Antarctic telescope is thus orders of magnitude larger than for a similar telescope located at a mid-latitude site; this large field of view obviates the necessity for multiconjugate adaptive-optics systems that use multiple laser guide stars. These results, combined with the low infrared sky backgrounds, indicate that the Antarctic plateau is the best site on Earth at which to perform high-resolution imaging with large telescopes, either over large fields of view or with appreciable sky coverage. Preliminary site-testing results obtained recently from the Dome Concordia station indicate that this site is far superior to even the South Pole.

  10. Infrastructure for large space telescopes

    NASA Astrophysics Data System (ADS)

    MacEwen, Howard A.; Lillie, Charles F.

    2016-10-01

    It is generally recognized (e.g., in the National Aeronautics and Space Administration response to recent congressional appropriations) that future space observatories must be serviceable, even if they are orbiting in deep space (e.g., around the Sun-Earth libration point, SEL2). On the basis of this legislation, we believe that budgetary considerations throughout the foreseeable future will require that large, long-lived astrophysics missions must be designed as evolvable semipermanent observatories that will be serviced using an operational, in-space infrastructure. We believe that the development of this infrastructure will include the design and development of a small to mid-sized servicing vehicle (MiniServ) as a key element of an affordable infrastructure for in-space assembly and servicing of future space vehicles. This can be accomplished by the adaptation of technology developed over the past half-century into a vehicle approximately the size of the ascent stage of the Apollo Lunar Module to provide some of the servicing capabilities that will be needed by very large telescopes located in deep space in the near future (2020s and 2030s). We specifically address the need for a detailed study of these servicing requirements and the current proposals for using presently available technologies to provide the appropriate infrastructure.

  11. Large aperture Fresnel telescopes/011

    SciTech Connect

    Hyde, R.A., LLNL

    1998-07-16

    At Livermore we`ve spent the last two years examining an alternative approach towards very large aperture (VLA) telescopes, one based upon transmissive Fresnel lenses rather than on mirrors. Fresnel lenses are attractive for VLA telescopes because they are launchable (lightweight, packagable, and deployable) and because they virtually eliminate the traditional, very tight, surface shape requirements faced by reflecting telescopes. Their (potentially severe) optical drawback, a very narrow spectral bandwidth, can be eliminated by use of a second (much smaller) chromatically-correcting Fresnel element. This enables Fresnel VLA telescopes to provide either single band ({Delta}{lambda}/{lambda} {approximately} 0.1), multiple band, or continuous spectral coverage. Building and fielding such large Fresnel lenses will present a significant challenge, but one which appears, with effort, to be solvable.

  12. Fermi's Large Area Telescope (LAT)

    NASA Video Gallery

    Fermi’s Large Area Telescope (LAT) is the spacecraft’s main scientificinstrument. This animation shows a gamma ray (purple) entering the LAT,where it is converted into an electron (red) and a...

  13. Wavefront Analysis of Adaptive Telescope

    NASA Technical Reports Server (NTRS)

    Hadaway, James B.; Hillman, Lloyd

    1997-01-01

    The motivation for this work came from a NASA Headquarters interest in investigating design concepts for a large space telescope employing active optics technology. Current and foreseeable launch vehicles will be limited to carrying around 4-5 meter diameter objects. Thus, if a large, filled-aperture telescope (6-20 meters in diameter) is to be placed in space, it will be required to have a deployable primary mirror. Such a mirror may be an inflatable membrane or a segmented mirror consisting of many smaller pieces. In any case, it is expected that the deployed primary will not be of sufficient quality to achieve diffraction-limited performance for its aperture size. Thus, an active optics system will be needed to correct for initial as well as environmentally-produced primary figure errors. Marshall Space Flight Center has developed considerable expertise in the area of active optics with the PAMELA test-bed. The combination of this experience along with the Marshall optical shop's work in mirror fabrication made MSFC the logical choice to lead NASA's effort to develop active optics technology for large, space-based, astronomical telescopes. Furthermore, UAH's support of MSFC in the areas of optical design, fabrication, and testing of space-based optical systems placed us in a key position to play a major role in the development of this future-generation telescope. A careful study of the active optics components had to be carried out in order to determine control segment size, segment quality, and segment controllability required to achieve diffraction-limited resolution with a given primary mirror. With this in mind, UAH undertook the following effort to provide NASA/MSFC with optical design and analysis support for the large telescope study. All of the work performed under this contract has already been reported, as a team member with MSFC, to NASA Headquarters in a series of presentations given between May and December of 1995. As specified on the delivery

  14. Toward Adaptive X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Atkins, Carolyn; Button, Tim W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peer; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Kolodziejczak, Jeffrey J.; Michette, Alan G.; Ramsey, Brian D.; Reid, Paul B.; Rodriguez Sanmartin, Daniel; Saha, Timo T.; Schwartz, Daniel A.; Trolier-McKinstry, Susan; Wilke, Rudeger H. T.; Willingale, Richard; Zhang, William W.

    2011-01-01

    Future x-ray observatories will require high-resolution (less than 1 inch) optics with very-large-aperture (greater than 25 square meter) areas. Even with the next generation of heavy-lift launch vehicles, launch-mass constraints and aperture-area requirements will limit the surface areal density of the grazing-incidence mirrors to about 1 kilogram per square meter or less. Achieving sub-arcsecond x-ray imaging with such lightweight mirrors will require excellent mirror surfaces, precise and stable alignment, and exceptional stiffness or deformation compensation. Attaining and maintaining alignment and figure control will likely involve adaptive (in-space adjustable) x-ray optics. In contrast with infrared and visible astronomy, adaptive optics for x-ray astronomy is in its infancy. In the middle of the past decade, two efforts began to advance technologies for adaptive x-ray telescopes: The Generation-X (Gen-X) concept studies in the United States, and the Smart X-ray Optics (SXO) Basic Technology project in the United Kingdom. This paper discusses relevant technological issues and summarizes progress toward adaptive x-ray telescopes.

  15. Real-time turbulence profiling with a pair of laser guide star Shack-Hartmann wavefront sensors for wide-field adaptive optics systems on large to extremely large telescopes.

    PubMed

    Gilles, L; Ellerbroek, B L

    2010-11-01

    Real-time turbulence profiling is necessary to tune tomographic wavefront reconstruction algorithms for wide-field adaptive optics (AO) systems on large to extremely large telescopes, and to perform a variety of image post-processing tasks involving point-spread function reconstruction. This paper describes a computationally efficient and accurate numerical technique inspired by the slope detection and ranging (SLODAR) method to perform this task in real time from properly selected Shack-Hartmann wavefront sensor measurements accumulated over a few hundred frames from a pair of laser guide stars, thus eliminating the need for an additional instrument. The algorithm is introduced, followed by a theoretical influence function analysis illustrating its impulse response to high-resolution turbulence profiles. Finally, its performance is assessed in the context of the Thirty Meter Telescope multi-conjugate adaptive optics system via end-to-end wave optics Monte Carlo simulations.

  16. Large aperture diffractive space telescope

    DOEpatents

    Hyde, Roderick A.

    2001-01-01

    A large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass "aiming" at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The objective lens includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the objective lens, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets which may be either earth bound or celestial.

  17. World atlas of large optical telescopes

    NASA Technical Reports Server (NTRS)

    Meszaros, S. P.

    1979-01-01

    By 1980 there will be approximately 100 large optical telescopes in the world with mirror or lens diameters of one meter (39 inches) and larger. This atlas gives information on these telescopes and shows their locations on continent-sized maps. Observatory locations considered suitable for the construction of future large telescopes are also shown.

  18. Large space telescope, phase A. Volume 3: Optical telescope assembly

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development and characteristics of the optical telescope assembly for the Large Space Telescope are discussed. The systems considerations are based on mission-related parameters and optical equipment requirements. Information is included on: (1) structural design and analysis, (2) thermal design, (3) stabilization and control, (4) alignment, focus, and figure control, (5) electronic subsystem, and (6) scientific instrument design.

  19. Cumulative Reconstructor: fast wavefront reconstruction algorithm for Extremely Large Telescopes.

    PubMed

    Rosensteiner, Matthias

    2011-10-01

    The Cumulative Reconstructor (CuRe) is a new direct reconstructor for an optical wavefront from Shack-Hartmann wavefront sensor measurements. In this paper, the algorithm is adapted to realistic telescope geometries and the transition from modified Hudgin to Fried geometry is discussed. After a discussion of the noise propagation, we analyze the complexity of the algorithm. Our numerical tests confirm that the algorithm is very fast and accurate and can therefore be used for adaptive optics systems of Extremely Large Telescopes.

  20. Wind buffeting of large telescopes.

    PubMed

    MacMynowski, Douglas G; Andersen, Torben

    2010-02-01

    Unsteady wind loads due to turbulence within the telescope enclosure are one of the largest dynamic disturbances for ground-based optical telescopes. The desire to minimize the response to the wind influences the design of the telescope enclosure, structure, and control systems. There is now significant experience in detailed integrated modeling to predict image jitter due to wind. Based on this experience, a relatively simple model is proposed that is verified (from a more detailed model) to capture the relevant physics. In addition to illustrating the important elements of the telescope design that influence wind response, this model is used to understand the sensitivity of telescope image jitter to a wide range of design parameters.

  1. Performance of the restoration of interferometric images from the Large Binocular Telescope: the effects of angular coverage and partial adaptive optics correction

    NASA Astrophysics Data System (ADS)

    Carbillet, Marcel; Correia, Serge; Boccacci, Patrizia; Bertero, Mario

    2003-02-01

    This presentation reports the status of our study concerning the imaging properties of the Large Binocular Telescope (LBT) interferometer, and namely the effect of limited angular coverage and partial adaptive optics (AO) correction. The limitation in angular coverage, together with the correlated problem of angular smearing due to time-averaging of the interferometric images, is investigated for relevant cases depending on the declination of the observed object. Results are encouraging even in case of incomplete coverage. Partial AO-correction can result in a wide range of image quality, but can also create significant differences within a same field-of-view, especially between a suitable reference star to be used for post-observation multiple deconvolution and the observed object. Our study deals with both the problem of space-variance of the AO-corrected point-spread function, and that of global quality of the AO-correction. Uniformity, rather than global quality, is found to be the key-problem. After considering the single-conjugate AO case, we reach to some conclusions for the more interesting, and actually wide-field, case implying multi-conjugate AO. The whole study is performed on different types of object, from binary stars to diffuse objects, and a combined one with a high-dynamic range.

  2. European Extremely Large Telescope: progress report

    NASA Astrophysics Data System (ADS)

    Tamai, R.; Spyromilio, J.

    2014-07-01

    The European Extremely Large Telescope is a project of the European Southern Observatory to build and operate a 40-m class optical near-infrared telescope. The telescope design effort is largely concluded and construction contracts are being placed with industry and academic/research institutes for the various components. The siting of the telescope in Northern Chile close to the Paranal site allows for an integrated operation of the facility providing significant economies. The progress of the project in various areas is presented in this paper and references to other papers at this SPIE meeting are made.

  3. Compliant Baffle for Large Telescope Daylight Imaging

    DTIC Science & Technology

    2014-09-01

    Compliant Baffle for Large Telescope Daylight Imaging Steven Griffin, Andrew Whiting, Shawn Haar The Boeing Company Stacie Williams Air Force...not impact wind loading induced jitter on the 3.6 m telescope . Analysis was performed to design a compliant baffle out of a synthetic fabric that...will be a comparison of angular rate sensors and accelerometers mounted on the telescope . 1.0 INTRODUCTION Unsteady wind loading is the largest

  4. Eyeglass. 1. Very large aperture diffractive telescopes.

    PubMed

    Hyde, R A

    1999-07-01

    The Eyeglass is a very large aperture (25-100-m) space telescope consisting of two distinct spacecraft, separated in space by several kilometers. A diffractive lens provides the telescope s large aperture, and a separate, much smaller, space telescope serves as its mobile eyepiece. Use of a transmissive diffractive lens solves two basic problems associated with very large aperture space telescopes; it is inherently launchable (lightweight, packagable, and deployable) it and virtually eliminates the traditional, very tight surface shape tolerances faced by reflecting apertures. The potential drawback to use of a diffractive primary (very narrow spectral bandwidth) is eliminated by corrective optics in the telescope s eyepiece; the Eyeglass can provide diffraction-limited imaging with either single-band (Deltalambda/lambda approximately 0.1), multiband, or continuous spectral coverage.

  5. Eyeglass. 1. Very large aperture diffractive telescopes

    SciTech Connect

    Hyde, R.A.

    1999-07-01

    The Eyeglass is a very large aperture (25{endash}100-m) space telescope consisting of two distinct spacecraft, separated in space by several kilometers. A diffractive lens provides the telescope{close_quote}s large aperture, and a separate, much smaller, space telescope serves as its mobile eyepiece. Use of a transmissive diffractive lens solves two basic problems associated with very large aperture space telescopes; it is inherently launchable (lightweight, packagable, and deployable) it and virtually eliminates the traditional, very tight surface shape tolerances faced by reflecting apertures. The potential drawback to use of a diffractive primary (very narrow spectral bandwidth) is eliminated by corrective optics in the telescope{close_quote}s eyepiece; the Eyeglass can provide diffraction-limited imaging with either single-band ({Delta}{lambda}/{lambda}{approximately}0.1), multiband, or continuous spectral coverage. {copyright} 1999 Optical Society of America

  6. Large aperture millimeter/submillimeter telescope: which is more cost-effective, aperture synthesis telescope versus large single dish telescope?

    NASA Astrophysics Data System (ADS)

    Iguchi, Satoru; Saito, Masao

    2016-07-01

    The Atacama Large Millimeter/submillimeter Array (ALMA) consists of 66 antennas with the aperture equivalent to a 91-m diameter antenna. The Green Bank Telescope (GBT) is the world's largest, 100-m diameter telescope in the wavelength range of 3 mm to 30 cm. The Large Millimeter Telescope (LMT) will be the world's largest, 50-m diameter, steerable millimeter-wavelength telescope. The Cerro Chajnantor Atacama Telescope (CCAT) will be the world's largest, 25-m diameter, submillimeter-wavelength telescope. We will investigate advantages and disadvantages of both the aperture synthesis telescope and the large single-dish telescope taking the cost effectiveness into consideration, and will propose the design of antenna structure for a future telescope project at millimeter and submillimeter wavelengths.

  7. James Webb Space Telescope: large deployable cryogenic telescope in space

    NASA Astrophysics Data System (ADS)

    Lightsey, Paul A.; Atkinson, Charles; Clampin, Mark; Feinberg, Lee D.

    2012-01-01

    The James Webb Space Telescope (JWST) is an infrared space telescope designed to explore four major science themes: first light and reionization, the assembly of galaxies, the birth of stars and protoplanetary systems, and planetary systems and origins of life. JWST is a segmented architecture telescope with an aperture of 6.6 m. It will operate at cryogenic temperature (40 K), achieved via passive cooling, in an orbit about the Earth-Sun second Lagrange point (L2). Passive cooling is facilitated by means of a large sunshield that provides thermal isolation and protection from direct illumination from the Sun. The large size of the telescope and spacecraft systems require that they are stowed for launch in a configuration that fits the Ariane 5 fairing, and then deployed after launch. Routine wavefront sensing and control measurements are used to achieve phasing of the segmented primary mirror and initial alignment of the telescope. A suite of instruments will provide the capability to observe over a spectral range from 0.6- to 27-μm wavelengths with imaging and spectroscopic configurations. An overview is presented of the architecture and selected optical design features of JWST are described.

  8. Adaptive Optics at the World’s Biggest Optical Telescope

    DTIC Science & Technology

    2010-09-01

    bottom up. The reflective, and deformable, component of each of the LBT’s mirrors is a concave Zerodur shell, 1.6 mm in average thickness and 911 mm in...Physik, 85748 Garching, Germany ABSTRACT The Large Binocular Telescope (LBT) on Mt. Graham, Arizona, comprises two 8.4 m primary mirrors on a...adaptive optics (AO) was incorporated into the design through two adaptive secondary mirrors (ASM), each 91 cm in diameter with 672 actuators, which feed

  9. Solar Rejection Filter for Large Telescopes

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid; Lesh, James

    2009-01-01

    To reject solar radiation photons at the front aperture for large telescopes, a mosaic of large transmission mode filters is placed in front of the telescope or at the aperture of the dome. Filtering options for effective rejection of sunlight include a smaller filter down-path near the focus of the telescope, and a large-diameter filter located in the front of the main aperture. Two types of large filters are viable: reflectance mode and transmittance mode. In the case of reflectance mode, a dielectric coating on a suitable substrate (e.g. a low-thermal-expansion glass) is arranged to reflect only a single, narrow wavelength and to efficiently transmit all other wavelengths. These coatings are commonly referred to as notch filter. In this case, the large mirror located in front of the telescope aperture reflects the received (signal and background) light into the telescope. In the case of transmittance mode, a dielectric coating on a suitable substrate (glass, sapphire, clear plastic, membrane, and the like) is arranged to transmit only a single wavelength and to reject all other wavelengths (visible and near IR) of light. The substrate of the large filter will determine its mass. At first glance, a large optical filter with a diameter of up to 10 m, located in front of the main aperture, would require a significant thickness to avoid sagging. However, a segmented filter supported by a structurally rugged grid can support smaller filters. The obscuration introduced by the grid is minimal because the total area can be made insignificant. This configuration can be detrimental to a diffraction- limited telescope due to diffraction effects at the edges of each sub-panel. However, no discernable degradation would result for a 20 diffraction-limit telescope (a photon bucket). Even the small amount of sagging in each subpanel should have minimal effect in the performance of a non-diffraction limited telescope because the part has no appreciable optical power. If the

  10. New technology for large optical telescopes

    NASA Astrophysics Data System (ADS)

    de Jonge, M. J.

    1983-05-01

    A recurrent topic arising in the discussions about new generation large optical telescopes is related to the economic advantages of lightweight reflector surfaces. A description is given of new technologies which might be suited for the construction of lightweight telescopes of low cost. One technology involves the use of sandwich structures, which include aluminum layers, separated by aluminum honeycomb layers. The availability of these structures, which have been developed for aircraft manufacture, has led various groups to study the feasibility of a use of sandwich materials for the manufacture of highly accurate reflecting surfaces, as required for millimeter and submillimeter wave telescopes. The results of these studies are discussed.

  11. Adaptive Optics at the World's Biggest Optical Telescope

    NASA Astrophysics Data System (ADS)

    Hart, M.; Esposito, S.; Rabien, S.

    2010-09-01

    The Large Binocular Telescope (LBT) on Mt. Graham, Arizona, comprises two 8.4 m primary mirrors on a common mount. The two apertures will be co-phased to create a single telescope with 110 m2 of collecting area and 22.7 m baseline. From the outset, adaptive optics (AO) was incorporated into the design through two adaptive secondary mirrors (ASM), each 91 cm in diameter with 672 actuators, which feed all of the instruments mounted at the telescope's four pairs of Gregorian foci. The first ASM has now seen first light on sky with natural guide stars. Strehl ratios at 1.6 μm under average seeing are estimated to be ~80%, and diffraction-limited performance is maintained for stars down to magnitude 15. At the same time, pioneering work at the 6.5 m MMT telescope has for the first time shown the compelling benefits of ground-layer AO compensation. This technique relies on the signals from multiple laser beacons to sense and correct aberration arising close to the telescope with the result that near IR seeing is reduced by a factor of 2-3 over a field of many arc minutes. Building on these efforts at both telescopes, a project is underway to enhance the LBT's AO capability by the addition of wavefront sensing with multiple laser guide stars. The Advanced Rayleigh Ground-layer adaptive Optics System (ARGOS) is now in the construction phase. We provide an overview of ARGOS and how it foreshadows AO systems destined for the 30 m class telescopes of tomorrow.

  12. Enclosure of the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Salinari, Piero; Hill, John M.

    1994-06-01

    We describe the enclosure of the Large Binocular Telescope, now in a detailed design phase. The enclosure is co-rotating with the telescope, includes a service floor carrying all telescope utilities, and is characterized by two large portal shutters, which open laterally leaving the air flow at the front and at the back of the telescope essentially unobstructed. Large louvers on the side walls and wind shields with variable permeability at the front and back openings are used to control the air flow in different wind conditions. The inner and outer surfaces of the enclosure are designed to obtain short thermal time constant and close equilibrium with ambient air. Forced air circulation in the outer skin of the enclosure is used for better heat exchange and, with electrical heaters, for melting snow. The interaction of the whole building with the natural air flow in conditions representative of those encountered at the specific site on Mt. Graham was the subject of extensive water channel measurements on a model of the building and of the surrounding environment. The flow patterns obtained in the simulations show no mixing of lower air layers with those at the level of the primary mirrors or above. The handling scheme for large equipment, including the primary mirror cells and the bell-jar for aluminizing of the mirrors on board the telescope, is based on a large bridge crane that can transfer instruments and maintenance equipment to the telescope and to the service floor from the storage and maintenance area at ground level.

  13. Large telescopes and the art of bridge building

    NASA Astrophysics Data System (ADS)

    Kärcher, H. J.

    2008-07-01

    In the last decade the evolution of large or extreme large earthbound optical telescopes speeded up in an unforeseen manner. The technological development is driven by the issues of the complex and challenging active and adaptive optics. But the design of the telescope structure and mechanics - as the backbone of the optics - is also increasing in the importance for costs and later performance. Structural mechanics is an old art, starting a long time ago with building bridges and gothic cathedrals etc. Essence of this art is the understanding of forces, load paths, weight and balance, strength and related deformations. The paper develops a perception of the structural subsystems of telescopes ("tube structure", "alidade") from the viewpoint of structural mechanics as learned from the "bridge builders". Actual example is a proposal for the design of ESO's 42m E-ELT.

  14. Cooling Technology for Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    DiPirro, Michael; Cleveland, Paul; Durand, Dale; Klavins, Andy; Muheim, Daniella; Paine, Christopher; Petach, Mike; Tenerelli, Domenick; Tolomeo, Jason; Walyus, Keith

    2007-01-01

    NASA's New Millennium Program funded an effort to develop a system cooling technology, which is applicable to all future infrared, sub-millimeter and millimeter cryogenic space telescopes. In particular, this technology is necessary for the proposed large space telescope Single Aperture Far-Infrared Telescope (SAFIR) mission. This technology will also enhance the performance and lower the risk and cost for other cryogenic missions. The new paradigm for cooling to low temperatures will involve passive cooling using lightweight deployable membranes that serve both as sunshields and V-groove radiators, in combination with active cooling using mechanical coolers operating down to 4 K. The Cooling Technology for Large Space Telescopes (LST) mission planned to develop and demonstrate a multi-layered sunshield, which is actively cooled by a multi-stage mechanical cryocooler, and further the models and analyses critical to scaling to future missions. The outer four layers of the sunshield cool passively by radiation, while the innermost layer is actively cooled to enable the sunshield to decrease the incident solar irradiance by a factor of more than one million. The cryocooler cools the inner layer of the sunshield to 20 K, and provides cooling to 6 K at a telescope mounting plate. The technology readiness level (TRL) of 7 will be achieved by the active cooling technology following the technology validation flight in Low Earth Orbit. In accordance with the New Millennium charter, tests and modeling are tightly integrated to advance the technology and the flight design for "ST-class" missions. Commercial off-the-shelf engineering analysis products are used to develop validated modeling capabilities to allow the techniques and results from LST to apply to a wide variety of future missions. The LST mission plans to "rewrite the book" on cryo-thermal testing and modeling techniques, and validate modeling techniques to scale to future space telescopes such as SAFIR.

  15. Towards a European Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    2006-07-01

    ESO, the European Organisation for Astronomical Research in the Southern Hemisphere, is taking an important step towards the realisation of a new, giant telescope for Europe's astronomers, by creating the ESO Extremely Large Telescope Project Office. It will be headed by Jason Spyromilio, formerly La Silla Paranal Observatory Director. "We believe that the European Extremely Large Telescope (E-ELT) is essential if we are to ensure the continued competitiveness of the astronomical community in ESO's member-states. This goal can be achieved in a timely manner through ESO and the community working closely together, and the establishment of the ELT project office is a significant step in this direction", says Catherine Cesarsky, ESO's Director General. "In its December 2004 Resolution, ESO's Council requested ESO to launch the construction of an ELT on a competitive timescale", says Jason Spyromilio. "The creation of the ELT Project Office is thus the logical step, following on the large amount of preparatory work on ELTs carried out in Europe, for instance in the framework of the OWL Conceptual Study [1], the EU co-funded ELT Design Study project [2] and more recently by the five ELT thematic working groups established by the Director General." The ESO ELT Project Office, which is part of the ESO Telescope Systems Division (TSD), will work closely together with experts, from both ESO and the European scientific community, represented in the ELT Science and Engineering Working Group and in a Standing Review Committee established by the ESO Council. "ESO aims to put the European Extremely Large Telescope on a 'fast-track', within a wide collaboration with its community and with the direct involvement of industry", says Roberto Gilmozzi, head of the ESO TSD and E-ELT Principal Investigator. A baseline design is to be presented to the ESO Council at the end of 2006. The plan is a telescope with a primary mirror between 30 and 60 metres in diameter and a financial envelope

  16. Large Synoptic Survey Telescope mount final design

    NASA Astrophysics Data System (ADS)

    Callahan, Shawn; Gressler, William; Thomas, Sandrine J.; Gessner, Chuck; Warner, Mike; Barr, Jeff; Lotz, Paul J.; Schumacher, German; Wiecha, Oliver; Angeli, George; Andrew, John; Claver, Chuck; Schoening, Bill; Sebag, Jacques; Krabbendam, Victor; Neill, Doug; Hileman, Ed; Muller, Gary; Araujo, Constanza; Orden Martinez, Alfredo; Perezagua Aguado, Manuel; García-Marchena, Luis; Ruiz de Argandoña, Ismael; Romero, Francisco M.; Rodríguez, Ricardo; Carlos González, José; Venturini, Marco

    2016-08-01

    This paper describes the status and details of the large synoptic survey telescope1,2,3 mount assembly (TMA). On June 9th, 2014 the contract for the design and build of the large synoptic survey telescope mount assembly (TMA) was awarded to GHESA Ingeniería y Tecnología, S.A. and Asturfeito, S.A. The design successfully passed the preliminary design review on October 2, 2015 and the final design review January 29, 2016. This paper describes the detailed design by subsystem, analytical model results, preparations being taken to complete the fabrication, and the transportation and installation plans to install the mount on Cerro Pachón in Chile. This large project is the culmination of work by many people and the authors would like to thank everyone that has contributed to the success of this project.

  17. GLAST Large Area Telescope Multiwavelength Planning

    SciTech Connect

    Reimer, O.; Michelson, P.F.; Cameron, R.A.; Digel, S.W.; Thompson, D.J.; Wood, K.S.

    2007-01-03

    Gamma-ray astrophysics depends in many ways on multiwavelength studies. The Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) Collaboration has started multiwavelength planning well before the scheduled 2007 launch of the observatory. Some of the high-priority multiwavelength needs include: (1) availability of contemporaneous radio and X-ray timing of pulsars; (2) expansion of blazar catalogs, including redshift measurements; (3) improved observations of molecular clouds, especially at high galactic latitudes; (4) simultaneous broad-band blazar monitoring; (5) characterization of gamma-ray transients, including gamma ray bursts; (6) radio, optical, X-ray and TeV counterpart searches for reliable and effective sources identification and characterization. Several of these activities are needed to be in place before launch.

  18. GLAST Large Area Telescope Multiwavelength Planning

    NASA Technical Reports Server (NTRS)

    Reimer, O.; Michelson, P. F.; Cameron, R. A.; Digel, S. W.; Thompson, D. J.; Wood, K. S.

    2007-01-01

    Gamma-ray astrophysics depends in many ways on multiwavelength studies. The Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) Collaboration has started multiwavelength planning well before the scheduled 2007 launch of the observatory. Some of the high-priority multiwavelength needs include: (1) availability of contemporaneous radio and X-ray timing of pulsars; (2) expansion of blazar catalogs, including redshift measurements; (3) improved observations of molecular clouds, especially at high galactic latitudes; (4) simultaneous broad-spectrum blazar monitoring; (5) characterization of gamma-ray transients, including gamma ray bursts; (6) radio, optical, X-ray and TeV counterpart searches for reliable and effective sources identification and characterization. Several of these activities are needed to be in place before launch.

  19. Very Large Aperture Diffractive Space Telescope

    SciTech Connect

    Hyde, Roderick Allen

    1998-04-20

    A very large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass ''aiming'' at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The magnifying glass includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the magnifying glass, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets.

  20. Operations analysis for a large lunar telescope

    NASA Technical Reports Server (NTRS)

    Thyen, Christopher

    1992-01-01

    Consideration is given to a study of the operations and assembly of a 16-m large lunar telescope (LLT), which deals with the operations and assembly of the telescope from LEO to the lunar surface for assembly. The study of LLT operations and assembly is broken down into three divisions to allow easier operations analysis: earth to orbit operations, LEO operations (transfer to lunar surface operations), and lunar surface operations. The following guidelines were set down to ensure a reasonable starting point for a large, lunar, untended installation: the existence of a lunar base, a space transportation system from LEO to the lunar surface, continuous manning of the lunar base during the assembly period, and availability/capability to perform lunar assembly with the lunar base crew. The launch/vehicle packaging options, lunar site selection and assembly options, and assembly crew assumptions are discussed.

  1. Moving toward queue operations at the Large Binocular Telescope Observatory

    NASA Astrophysics Data System (ADS)

    Edwards, Michelle L.; Summers, Doug; Astier, Joseph; Suarez Sola, Igor; Veillet, Christian; Power, Jennifer; Cardwell, Andrew; Walsh, Shane

    2016-07-01

    The Large Binocular Telescope Observatory (LBTO), a joint scientific venture between the Instituto Nazionale di Astrofisica (INAF), LBT Beteiligungsgesellschaft (LBTB), University of Arizona, Ohio State University (OSU), and the Research Corporation, is one of the newest additions to the world's collection of large optical/infrared ground-based telescopes. With its unique, twin 8.4m mirror design providing a 22.8 meter interferometric baseline and the collecting area of an 11.8m telescope, LBT has a window of opportunity to exploit its singular status as the "first" of the next generation of Extremely Large Telescopes (ELTs). Prompted by urgency to maximize scientific output during this favorable interval, LBTO recently re-evaluated its operations model and developed a new strategy that augments classical observing with queue. Aided by trained observatory staff, queue mode will allow for flexible, multi-instrument observing responsive to site conditions. Our plan is to implement a staged rollout that will provide many of the benefits of queue observing sooner rather than later - with more bells and whistles coming in future stages. In this paper, we outline LBTO's new scientific model, focusing specifically on our "lean" resourcing and development, reuse and adaptation of existing software, challenges presented from our one-of-a-kind binocular operations, and lessons learned. We also outline further stages of development and our ultimate goals for queue.

  2. Current Status of the Large Millimeter Telescope

    NASA Astrophysics Data System (ADS)

    Chavez, M.; LMT Team

    2014-03-01

    I will briefly describe the current status of the Large Millimeter Telescope (LMT), the near-term plans for the telescope and the initial suite of instrumentation. I will also summarize some of the results of the Early Science Phase that took place in the summer of 2013. The LMT is a bi-national collaboration between Mexico and the USA, led by the Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) and the University of Massachusetts at Amherst, to construct, commission and operate a 50m-diameter millimeter-wave radio telescope. Construction activities are complete at the 4600m LMT site on the summit of Volcan Sierra Negra, an extinct volcano in the Mexican state of Puebla. First light with the LMT (inner 32mdiameter) was successfully conducted in June and July of 2011, as well as the Early Science Phase in May-July 2013 with observations at both the 3 and 1.1mm wave-bands. The LMT antenna, outfitted with its initial complement of scientific instruments, will be a world-leading scientific research facility for millimeter-wave astronomy.

  3. Large Binocular Telescope pre-assembly

    NASA Astrophysics Data System (ADS)

    Miglietta, Luciano; Anaclerio, E.; Castelli, G.; Gallieni, Daniele; Marchiori, Gianpietro; Rossettini, P.; Tassan Din, P.; Tomelleri, R.; Villa, G.; Zanon, Alberto

    2000-08-01

    The Large Binocular Telescope is currently in the pre- assembly phase at the Ansaldo Energia workshop in Milan. Since late 1998 the manufacturing of the Azimuth and Elevation structures has been taken place in North Italy along with the main auxiliary equipments, and since September 1999, the Azimuth Ring have been assembled and aligned on the new concrete foundation poured months before in the same area. The pre-assembly activity in Italy will take some months more from now as the final acceptance tests are scheduled now for December 2000; then the whole telescope steel structure will be disassembled and shipped to Mt. Graham where the final assembling phase will start in spring 2001. In this paper, the authors, part of some industrial companies and public institutes main character in this scientific and technical challenges, briefly describe the manufacturing and the machining processes of the main telescope components, the reached results and the procedures adopted during the pre-assembling as overall test bench for the final erection in Arizona.

  4. Supernova Remnants with Fermi Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Caragiulo, M.; Di Venere, L.

    2017-03-01

    The Large Area Telescope (LAT), on-board the Fermi satellite, proved to be, after 8 years of data taking, an excellent instrument to detect and observe Supernova Remnants (SNRs) in a range of energies running from few hundred MeV up to few hundred GeV. It provides essential information on physical processes that occur at the source, involving both accelerated leptons and hadrons, in order to understand the mechanisms responsible for the primary Cosmic Ray (CR) acceleration. We show the latest results in the observation of Galactic SNRs by Fermi-LAT.

  5. Bimorph mirrors for adaptive optics in space telescopes

    NASA Astrophysics Data System (ADS)

    Alaluf, D.; Bastaits, R.; Wang, K.; Horodinca, M.; Burda, I.; Martic, G.; Preumont, A.

    2016-07-01

    This paper discusses a concept of bimorph deformable mirror used in adaptive optics to compensate for manufacturing errors, gravity release and thermal distortion affecting large lightweight mirrors in space telescopes. The mirror consists of a single-crystal Silicon wafer (D=75 mm t=500μm) covered with an optical coating on the front side and an array of 25 independent PZT actuators acting in d31 mode on the back side. The mirror is mounted on an isostatic support with three linear PZT actuators controlling the rigid-body motion. The paper presents the experimental results obtained with this design and a new, more compact alternative.

  6. The LATT way towards large active primaries for space telescopes

    NASA Astrophysics Data System (ADS)

    Briguglio, Runa; Arcidiacono, Carmelo; Xompero, Marco; Lisi, Franco; Riccardi, Armando; Biasi, Roberto; Patauner, Christian; Gallieni, Daniele; Lazzarini, Paolo; Tintori, Matteo; d'Amato, Francesco; Pucci, Mauro; Duò, Fabrizio; Vettore, Christian; Zuccaro Marchi, Alessandro

    2016-07-01

    The Large Aperture Telescope Technology (LATT) goes beyond the current paradigm of future space telescopes, based on a deformable mirror in the pupil relay. Through the LATT project we demonstrated the concept of a low-weight active primary mirror, whose working principle and control strategy benefit from two decades of advances in adaptive optics for ground-based telescopes. We developed a forty centimeter spherical mirror prototype, with an areal density lower than 17 kg/m2, controlled through contactless voice coil actuators with co-located capacitive position sensors. The prototype was subjected to thermo-vacuum, vibration and optical tests, to push its technical readiness toward level 5. In this paper we present the background and the outcomes of the LATT activities under ESA contract (TRP programme), exploring the concept of a lightweight active primary mirror for space telescopes. Active primaries will open the way to very large segmented apertures, actively shaped, which can be lightweight, deployable and accurately phased once in flight.

  7. The Large Binocular Telescope's ARGOS ground-layer AO system

    NASA Astrophysics Data System (ADS)

    Hart, M.; Rabien, S.; Busoni, L.; Barl, L.; Bechmann, U.; Bonaglia, M.; Boose, Y.; Borelli, J.; Bluemchen, T.; Carbonaro, L.; Connot, C.; Deysenroth, M.; Davies, R.; Durney, O.; Elberich, M.; Ertl, T.; Esposito, S.; Gaessler, W.; Gasho, V.; Gemperlein, H.; Hubbard, P.; Kanneganti, S.; Kulas, M.; Newman, K.; Noenickx, J.; de Xivry, G.; Qirrenback, A.; Rademacher, M.; Schwab, C.; Storm, J.; Vaitheeswaran, V.; Weigelt, G.; Ziegleder, J.

    2011-09-01

    ARGOS, the laser-guided adaptive optics system for the Large Binocular Telescope (LBT), is now under construction at the telescope. By correcting atmospheric turbulence close to the telescope, the system is designed to deliver high resolution near infrared images over a field of 4 arc minute diameter. ARGOS is motivated by a successful prototype multi-laser guide star system on the 6.5 m MMT telescope, results from which are presented in this paper. At the LBT, each side of the twin 8.4 m aperture is being equipped with three Rayleigh laser guide stars derived from six 18 W pulsed green lasers and projected into two triangular constellations matching the size of the corrected field. The returning light is to be detected by wavefront sensors that are range gated within the seeinglimited depth of focus of the telescope. Wavefront correction will be introduced by the telescope’s deformable secondary mirrors driven on the basis of the average wavefront errors computed from the respective guide star constellation. Measured atmospheric turbulence profiles from the site lead us to expect that by compensating the ground-layer turbulence, ARGOS will deliver median image quality of about 0.2 arc sec in the near infrared bands. This will be exploited by a pair of multi-object near-IR spectrographs, LUCI1 and LUCI2, each with 4 arc minute field already operating on the telescope. In future, ARGOS will also feed two interferometric imaging instruments, the LBT Interferometer operating in the thermal infrared, and LINC-NIRVANA, operating at visible and near infrared wavelengths. Together, these instruments will offer very broad spectral coverage at the diffraction limit of the LBT’s combined aperture, 23 m in size.

  8. FERMI LARGE AREA TELESCOPE SECOND SOURCE CATALOG

    SciTech Connect

    Nolan, P. L.; Ajello, M.; Allafort, A.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Abdo, A. A.; Ackermann, M.; Antolini, E.; Bonamente, E.; Atwood, W. B.; Belfiore, A.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Ballet, J.; Bastieri, D.; Bignami, G. F. E-mail: Gino.Tosti@pg.infn.it E-mail: tburnett@u.washington.edu; and others

    2012-04-01

    We present the second catalog of high-energy {gamma}-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), derived from data taken during the first 24 months of the science phase of the mission, which began on 2008 August 4. Source detection is based on the average flux over the 24 month period. The second Fermi-LAT catalog (2FGL) includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits in terms of power-law, exponentially cutoff power-law, or log-normal forms. Also included are flux measurements in five energy bands and light curves on monthly intervals for each source. Twelve sources in the catalog are modeled as spatially extended. We provide a detailed comparison of the results from this catalog with those from the first Fermi-LAT catalog (1FGL). Although the diffuse Galactic and isotropic models used in the 2FGL analysis are improved compared to the 1FGL catalog, we attach caution flags to 162 of the sources to indicate possible confusion with residual imperfections in the diffuse model. The 2FGL catalog contains 1873 sources detected and characterized in the 100 MeV to 100 GeV range of which we consider 127 as being firmly identified and 1171 as being reliably associated with counterparts of known or likely {gamma}-ray-producing source classes.

  9. Fermi Large Area Telescope Second Source Catalog

    NASA Technical Reports Server (NTRS)

    Nolan, P. L.; Abdo, A. A.; Ackermann, M.; Ajello, M; Allafort, A.; Antolini, E; Bonnell, J.; Cannon, A.; Celik O.; Corbet, R.; Davis, D. S.; DeCesar, M. E.; Ferrara, E. C.; Gehrels, N.; Harding, A. K.; Hays, E.; Johnson, T. E.; McConville, W.; McEnery, J. E; Perkins, J. S.; Racusin, J. L; Scargle, J. D.; Stephens, T. E.; Thompson, D. J.; Troja, E.

    2012-01-01

    We present the second catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), derived from data taken during the first 24 months of the science phase of the mission, which began on 2008 August 4. Source detection is based on the average flux over the 24-month period. The Second Fermi-LAT catalog (2FGL) includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits in terms of power-law, exponentially cutoff power-law, or log-normal forms. Also included are flux measurements in 5 energy bands and light curves on monthly intervals for each source. Twelve sources in the catalog are modeled as spatially extended. We provide a detailed comparison of the results from this catalog with those from the first Fermi-LAT catalog (1FGL). Although the diffuse Galactic and isotropic models used in the 2FGL analysis are improved compared to the 1FGL catalog, we attach caution flags to 162 of the sources to indicate possible confusion with residual imperfections in the diffuse model. The 2FGL catalog contains 1873 sources detected and characterized in the 100 11eV to 100 GeV range of which we consider 127 as being firmly identified and 1171 as being reliably associated with counterparts of known or likely gamma-ray-producing source classes.

  10. The National Large Solar Telescope (NLST) of India

    NASA Astrophysics Data System (ADS)

    Hasan, S. S.

    2012-12-01

    The Indian National Large Solar Telescope (NLST) will be a state-of-the-art 2-m class telescope for carrying out high-resolution studies in the solar atmosphere. Recent numerical simulations suggest that crucial physical processes like vortex flow, dissipation of magnetic fields and the generation of MHD waves can occur efficiently over length scales of tens of kilometers. Current telescopes are unable to resolve solar feature to this level at visible wavelengths. NLST will not only achieve good spatial resolution, but will also have a high photon throughput in order to carry out spectropolarimetric observations to accurately measure vector magnetic fields in the solar atmosphere with a good signal to noise ratio. The main science goals of NLST include: a) Magnetic field generation and the solar cycle; b) Dynamics of magnetized regions; c) Helioseismology; d) Long term variability; e) Energetic phenomena and Activity; and f) Night time astronomy. The optical design of the telescope is optimized for high optical throughput and uses a minimum number of optical elements. A high order adaptive optics system is integrated as part of the design that works with a modest Fried's parameter of 7-cm to give diffraction limited performance. The telescope will be equipped with a suite of post-focus instruments including a high resolution spectrograph and a polarimeter. NLST will also be used for carrying out stellar observations during the night. The mechanical design of the telescope, building, and the innovative dome takes advantage of the natural air flush which will help to keep the open telescope in temperature equilibrium. Critical to the successful implementation of NLST is the selection of a site with optimum atmospheric properties, such as the number of sunshine hours and good "seeing" over long periods. A site characterization programme carried over several years has established the existence of suitable sites in the Ladakh region. After its completion, currently

  11. Primary mirror assemblies for large space telescopes

    NASA Astrophysics Data System (ADS)

    Malamed, Evgeny R.; Sokolsky, M. N.

    1995-09-01

    In this report are considered the basic problems which relate to developemnt, manufacture, experimental trying out, and usage of primary mirrors (PM) of the large space telescopes intended to perform distant sounding of the Earth. Attention is concentrated on development of weight-reduced passive mirrors which ensure more reliable operation of the telescope as a whole. In the report we expressed the opinion that it is quite possible to manufacture a passive weight-reduced PM if its diameter is equal approximately to 3 m. Materials which may be used for the manufacturing of PM are beryllium and silicon carbide, physical and mechanical parameters of which are the most preferable ones. But it should be taken into consideration that this is the glass ceramic of CO115M brand which has been mastered by the industry of Russia in the greatest extent. It was confirmed that parameters of this material remain unchanged during a long period of time. Constructions of the PM, made of glass ceramic, as well as constructions of holders intended to fix the mirror, are presented in this report. A holder is used first of all to prevent lowering of a PM surface quality after a mirror has been removed from a machine and fixed in a primary mirror assembly (PMA). At present two-layer construction of a PM is preferable. This construction consists of thick base including weight reduction structure, which is in a radius which is optimum from the standpoint of deformation of a mirror operating surface. In the process of manufacture a mirror is deprived of its weight with the use of special pneumatic off-loading elements. PMA is erected in vertical plane by means of using an interferometric inspection system. In the end of this report we expressed the views on an approach to engineering of a PM by taking into account potentialities both of space ships and of carrier rockets.

  12. Fermi Large Area Telescope First Source Catalog

    NASA Astrophysics Data System (ADS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Allafort, A.; Antolini, E.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bechtol, K.; Bellazzini, R.; Belli, F.; Berenji, B.; Bisello, D.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Bonnell, J.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Burnett, T. H.; Busetto, G.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Campana, R.; Canadas, B.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cavazzuti, E.; Ceccanti, M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Cillis, A. N.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Corbet, R.; Davis, D. S.; DeKlotz, M.; den Hartog, P. R.; Dermer, C. D.; de Angelis, A.; de Luca, A.; de Palma, F.; Digel, S. W.; Dormody, M.; Silva, E. do Couto e.; Drell, P. S.; Dubois, R.; Dumora, D.; Fabiani, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fortin, P.; Frailis, M.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giavitto, G.; Giebels, B.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Gustafsson, M.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.; Healey, S. E.; Hill, A. B.; Horan, D.; Hughes, R. E.; Iafrate, G.; Jóhannesson, G.; Johnson, A. S.; Johnson, R. P.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kerr, M.; Knödlseder, J.; Kocevski, D.; Kuss, M.; Lande, J.; Landriu, D.; Latronico, L.; Lee, S.-H.; Lemoine-Goumard, M.; Lionetto, A. M.; Llena Garde, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Makeev, A.; Marangelli, B.; Marelli, M.; Massaro, E.; Mazziotta, M. N.; McConville, W.; McEnery, J. E.; Michelson, P. F.; Minuti, M.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Mongelli, M.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakajima, H.; Nakamori, T.; Naumann-Godo, M.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paccagnella, A.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Pinchera, M.; Piron, F.; Porter, T. A.; Poupard, L.; Rainò, S.; Rando, R.; Ray, P. S.; Razzano, M.; Razzaque, S.; Rea, N.; Reimer, A.; Reimer, O.; Reposeur, T.; Ripken, J.; Ritz, S.; Rochester, L. S.; Rodriguez, A. Y.; Romani, R. W.; Roth, M.; Sadrozinski, H. F.-W.; Salvetti, D.; Sanchez, D.; Sander, A.; Saz Parkinson, P. M.; Scargle, J. D.; Schalk, T. L.; Scolieri, G.; Sgrò, C.; Shaw, M. S.; Siskind, E. J.; Smith, D. A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Starck, J.-L.; Stephens, T. E.; Striani, E.; Strickman, M. S.; Strong, A. W.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Tinebra, F.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Usher, T. L.; Van Etten, A.; Vasileiou, V.; Vilchez, N.; Vitale, V.; Waite, A. P.; Wallace, E.; Wang, P.; Watters, K.; Winer, B. L.; Wood, K. S.; Yang, Z.; Ylinen, T.; Ziegler, M.; Fermi LAT Collaboration

    2010-06-01

    We present a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), during the first 11 months of the science phase of the mission, which began on 2008 August 4. The First Fermi-LAT catalog (1FGL) contains 1451 sources detected and characterized in the 100 MeV to 100 GeV range. Source detection was based on the average flux over the 11 month period, and the threshold likelihood Test Statistic is 25, corresponding to a significance of just over 4σ. The 1FGL catalog includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and power-law spectral fits as well as flux measurements in five energy bands for each source. In addition, monthly light curves are provided. Using a protocol defined before launch we have tested for several populations of gamma-ray sources among the sources in the catalog. For individual LAT-detected sources we provide firm identifications or plausible associations with sources in other astronomical catalogs. Identifications are based on correlated variability with counterparts at other wavelengths, or on spin or orbital periodicity. For the catalogs and association criteria that we have selected, 630 of the sources are unassociated. Care was taken to characterize the sensitivity of the results to the model of interstellar diffuse gamma-ray emission used to model the bright foreground, with the result that 161 sources at low Galactic latitudes and toward bright local interstellar clouds are flagged as having properties that are strongly dependent on the model or as potentially being due to incorrectly modeled structure in the Galactic diffuse emission.

  13. The Large Binocular Telescope azimuth and elevation encoder system

    NASA Astrophysics Data System (ADS)

    Ashby, David S.; Sargent, Tom; Cox, Dan; Rosato, Jerry; Brynnel, Joar G.

    2008-08-01

    A typical high-resolution encoder interpolator relies on careful mechanical alignment of the encoder read-heads and tight electrical tolerances of the signal processing electronics to ensure linearity. As the interpolation factor increases, maintaining these tight mechanical and electrical tolerances becomes impractical. The Large Binocular Telescope (LBT) is designed to utilize strip-type encoders on the main axes. Because of the very large scale of the telescope, the accumulative length of the azimuth and elevation encoder strips exceeds 80 meters, making optical tape prohibitively expensive. Consequently, the designers of the LBT incorporated the far less expensive Farrand Controls Inductosyn® linear strip encoder to encode the positions of the main axes and the instrument rotators. Since the cycle pitch of these encoders is very large compared to that of optical strip encoders, the interpolation factor must also be large in order to achieve the 0.005 arcsecond encoder resolution as specified. The authors present a description of the innovative DSP-based hardware / software solution that adaptively characterizes and removes common systematic cycle-to-cycle encoder interpolation errors. These errors can be caused by mechanical misalignment, encoder manufacturing flaws, variations in electrical gain, signal offset or cross-coupling of the encoder signals. Simulation data are presented to illustrate the performance of the interpolation algorithm, and telemetry data are presented to demonstrate the actual performance of the LBT main-axis encoder system.

  14. Curvature wavefront sensing for the large synoptic survey telescope.

    PubMed

    Xin, Bo; Claver, Chuck; Liang, Ming; Chandrasekharan, Srinivasan; Angeli, George; Shipsey, Ian

    2015-10-20

    The Large Synoptic Survey Telescope (LSST) will use an active optics system (AOS) to maintain alignment and surface figure on its three large mirrors. Corrective actions fed to the LSST AOS are determined from information derived from four curvature wavefront sensors located at the corners of the focal plane. Each wavefront sensor is a split detector such that the halves are 1 mm on either side of focus. In this paper, we describe the extensions to published curvature wavefront sensing algorithms needed to address challenges presented by the LSST, namely the large central obscuration, the fast f/1.23 beam, off-axis pupil distortions, and vignetting at the sensor locations. We also describe corrections needed for the split sensors and the effects from the angular separation of different stars providing the intrafocal and extrafocal images. Lastly, we present simulations that demonstrate convergence, linearity, and negligible noise when compared to atmospheric effects when the algorithm extensions are applied to the LSST optical system. The algorithm extensions reported here are generic and can easily be adapted to other wide-field optical systems including similar telescopes with large central obscuration and off-axis curvature sensing.

  15. Active optics in Large Synoptic Survey Telescope

    NASA Astrophysics Data System (ADS)

    Liang, Ming; Krabbendam, Victor; Claver, Charles F.; Chandrasekharan, Srinivasan; Xin, Bo

    2012-09-01

    The Large Synoptic Survey Telescope (LSST) has a 3.5º field of view and F/1.2 focus that makes the performance quite sensitive to the perturbations of misalignments and mirror surface deformations. In order to maintain the image quality, LSST has an active optics system (AOS) to measure and correct those perturbations in a closed loop. The perturbed wavefront errors are measured by the wavefront sensors (WFS) located at the four corners of the focal plane. The perturbations are solved by the non-linear least square algorithm by minimizing the rms variation of the measured and baseline designed wavefront errors. Then the correction is realized by applying the inverse of the perturbations to the optical system. In this paper, we will describe the correction processing in the LSST AOS. We also will discuss the application of the algorithm, the properties of the sensitivity matrix and the stabilities of the correction. A simulation model, using ZEMAX as a ray tracing engine and MATLAB as an analysis platform, is set up to simulate the testing and correction loop of the LSST AOS. Several simulation examples and results are presented.

  16. Adaptive Optics Educational Outreach and the Giant Segmented Mirror Telescope

    NASA Astrophysics Data System (ADS)

    Sparks, R. T.; Pompea, S. M.; Walker, C. E.

    2008-06-01

    One of the limiting factors in telescope performance is atmospheric seeing. Atmospheric seeing limits the resolution of ground based optical telescopes. Even telescopes in good locations on top of mountains cannot achieve diffraction-limited resolution. Until recently, the only way to overcome this limitation was to use space-based telescopes. Adaptive Optics (AO) is a collection of technologies that measure the turbulence of Earth's atmosphere and compensate for the turbulence, resulting in high-resolution images without the expense and complexity of space based telescopes. Our Hands-On Optics program has developed activities that teach students how telescopes form images and make observations about the resolution of a telescope. We are developing materials for high school students to use in the study of adaptive optics. These activities include various ways to illustrate atmospheric distortion by using everyday materials such as bubble wrap and mineral oil. We will also illustrate how to demonstrate the workings of a Shack-Hartman sensor to measure atmospheric distortion through the use of a unique model. We will also show activities illustrating two techniques astronomers use to improve the image: tip-tilt mirrors and deformable mirrors. We are developing an activity where students learn how to use a tip-tilt mirror to keep an image focused at one point on a screen. The culminating activity has students learn to use a deformable mirror to correct a distorted wavefront. These activities are being developed in conjunction with the Education program for the Giant Segmented Mirror Telescope (GSMT).

  17. Support structures for large infrared telescopes

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1984-01-01

    An infrared telescope requires an accuracy of its reflecting surfaces of less than a micrometer. Future missions may require such accuracy from telescopes that are 20 meters or larger in diameter. The structure for supporting such a telescope will most probably take the form of a deep truss. Various approaches for constructing the primary mirror in space are illustrated. One that employs automated deployment of interconnected reflector-structure modules was described in detail. Estimates were made of the precision obtainable with properly configured truss structures and the required ability of active control systems for achieving the desired accuracy.

  18. Large open telescope: size-upscaling from DOT to LOT

    NASA Astrophysics Data System (ADS)

    Hammerschlag, Robert H.; Jaegers, Aswin P. L.; Bettonvil, Felix C. M.

    2003-02-01

    The design characteristics of a large open telescope (LOT) are: (i) an open tower with only pure translations of the platform under wind load; (ii) an open telescope construction with extremely stiff geometry and drives; (iii) simple optics with easy aligning and testing, but nevertheless suitable for large auxiliary equipment like spectrographs.

  19. The Large Millimeter Telescope (LMT) project

    NASA Astrophysics Data System (ADS)

    Baars, Jacob W.

    1998-07-01

    The LMT is a 50 m diameter telescope for operation to a wavelength of 1 mm from a high mountain site in central Mexico at a latitude of 19 degrees. The telescope is designed to address fundamental questions about the origin and formation of galaxies, clusters of galaxies as well as stars and planets. It is a joint project of the Mexican Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) in Tonantzintla, Puebla and the University of Massachusetts at Amherst. The telescope is in the Critical Design phase and completion of the basic assembly at the site is scheduled for the end of 2000. We describe historical and organizational aspects of the Project and present the major technical specifications and plans for realization.

  20. Estimating the cost of extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Stepp, Larry M.; Daggert, Larry G.; Gillett, Paul E.

    2003-01-01

    For future giant telescopes, control of construction and operation costs will be the key factor in their success. The best way to accomplish this cost control, while maximizing the performance of the telescope, will be through design-to-cost methods that use value engineering techniques to develop the most cost-effective design in terms of performance per dollar. This will require quantifiable measures of performance and cost, including: (1) a way of quantifying science value with scientific merit functions; (2) a way of predicting telescope performance in the presence of real-world disturbances by means of integrated modeling; and (3) a way of predicting the cost of multiple design configurations. Design-to-cost methods should be applied as early as possible in the project, since the majority of the life-cycle costs for the observatory will be locked in by choices made during the conceptual design phase. However, there is a dilemma: how can costs be accurately estimated for systems that have not yet been designed? This paper discusses cost estimating methods and describes their application to estimating the cost of ELTs, showing that the best method to use during the conceptual design phase is parametric cost estimating. Examples of parametric estimating techniques are described, based on experience gained from instrument development programs at NOAO. We then describe efforts underway to collect historical cost information and develop cost estimating relationships in preparation for the conceptual design phase of the Giant Segmented Mirror Telescope.

  1. European Extremely Large Telescope Site Characterization I: Overview

    NASA Astrophysics Data System (ADS)

    Vernin, Jean; Muñoz-Tuñón, Casiana; Sarazin, Marc; Vazquez Ramió, Héctor; Varela, Antonia M.; Trinquet, Hervé; Delgado, José Miguel; Jiménez Fuensalida, Jesús; Reyes, Marcos; Benhida, Abdelmajid; Benkhaldoun, Zouhair; García Lambas, Diego; Hach, Youssef; Lazrek, M.; Lombardi, Gianluca; Navarrete, Julio; Recabarren, Pablo; Renzi, Victor; Sabil, Mohammed; Vrech, Rubén

    2011-11-01

    The site for the future European Extremely Large Telescope (E-ELT) is already known to be Armazones, near Paranal (Chile). The selection was based on a variety of considerations, with an important one being the quality of the atmosphere for the astronomy planned for the ELT. We present an overview of the characterization of the atmospheric parameters of candidate sites, making use of standard procedures and instruments as carried out within the Framework Programme VI (FP6) of the European Union. We have achieved full characterization of the selected sites for the parameters considered. Further details on adaptive optics results and climatology will be the subject of two forthcoming articles. A summary of the results of the FP6 site-testing campaigns at the different sites is provided.

  2. Comparison of large aperture telescopes with parabolic and spherical primaries

    NASA Technical Reports Server (NTRS)

    Korsch, D.

    1986-01-01

    Quasi-Cassegrain-type four-mirror telescopes are compared to conventional two-mirror Cassegrain telescopes for use as high performance, very large aperture space telescopes. Spherical and parabolic primaries with continuous as well as segmented surfaces are considered. Imaging characteristics and misalignment sensitivities serve as the principal criteria of comparison. The evaluation shows that parabolic primaries yield superior wide-field performance, whereas spherical primaries hold distinct advantages regarding manufacturability and regarding certain alignment aspects in the case of segmentation.

  3. Simulating observations with HARMONI: the integral field spectrograph for the European Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Zieleniewski, Simon; Thatte, Niranjan; Kendrew, Sarah; Houghton, Ryan; Tecza, Matthias; Clarke, Fraser; Fusco, Thierry; Swinbank, Mark

    2014-07-01

    With the next generation of extremely large telescopes commencing construction, there is an urgent need for detailed quantitative predictions of the scientific observations that these new telescopes will enable. Most of these new telescopes will have adaptive optics fully integrated with the telescope itself, allowing unprecedented spatial resolution combined with enormous sensitivity. However, the adaptive optics point spread function will be strongly wavelength dependent, requiring detailed simulations that accurately model these variations. We have developed a simulation pipeline for the HARMONI integral field spectrograph, a first light instrument for the European Extremely Large Telescope. The simulator takes high-resolution input data-cubes of astrophysical objects and processes them with accurate atmospheric, telescope and instrumental effects, to produce mock observed cubes for chosen observing parameters. The output cubes represent the result of a perfect data reduc- tion process, enabling a detailed analysis and comparison between input and output, showcasing HARMONI's capabilities. The simulations utilise a detailed knowledge of the telescope's wavelength dependent adaptive op- tics point spread function. We discuss the simulation pipeline and present an early example of the pipeline functionality for simulating observations of high redshift galaxies.

  4. Spacecraft momentum management procedures. [large space telescope

    NASA Technical Reports Server (NTRS)

    Chen, L. C.; Davenport, P. B.; Sturch, C. R.

    1980-01-01

    Techniques appropriate for implementation onboard the space telescope and other spacecraft to manage the accumulation of momentum in reaction wheel control systems using magnetic torquing coils are described. Generalized analytical equations are derived for momentum control laws that command the magnetic torquers. These control laws naturally fall into two main categories according to the methods used for updating the magnetic dipole command: closed loop, in which the update is based on current measurements to achieve a desired torque instantaneously, and open-loop, in which the update is based on predicted information to achieve a desired momentum at the end of a period of time. Physical interpretations of control laws in general and of the Space Telescope cross product and minimum energy control laws in particular are presented, and their merits and drawbacks are discussed. A technique for retaining the advantages of both the open-loop and the closed-loop control laws is introduced. Simulation results are presented to compare the performance of these control laws in the Space Telescope environment.

  5. Wavefront Control for Space Telescope Applications Using Adaptive Optics

    DTIC Science & Technology

    2007-12-01

    SPACE TELESCOPE APPLICATIONS USING ADAPTIVE OPTICS by Matthew R. Allen December 2007 Thesis Advisor: Brij Agrawal Second Reader...ASTRONAUTICAL ENGINEERING from the NAVAL POSTGRADUATE SCHOOL December 2007 Author: Matthew R. Allen Approved by: Dr, Brij Agrawal...34 3. Direct Iterative Zonal Feedback Control ........................................ 35 4. Direct Iterative

  6. Monitoring the performance of the Southern African Large Telescope

    NASA Astrophysics Data System (ADS)

    Hettlage, Christian; Coetzee, Chris; Väisänen, Petri; Romero Colmenero, Encarni; Crawford, Steven M.; Kotze, Paul; Rabe, Paul; Hulme, Stephen; Brink, Janus; Maartens, Deneys; Browne, Keith; Strydom, Ockert; De Bruyn, David

    2016-07-01

    The efficient operation of a telescope requires awareness of its performance on a daily and long-term basis. This paper outlines the Fault Tracker, WebSAMMI and the Dashboard used by the Southern African Large Telescope (SALT) to achieve this aim. Faults are mostly logged automatically, but the Fault Tracker allows users to add and edit faults. The SALT Astronomer and SALT Operator record weather conditions and telescope usage with WebSAMMI. Various efficiency metrics are shown for different time periods on the Dashboard. A kiosk mode for displaying on a public screen is included. Possible applications for other telescopes are discussed.

  7. Open Principle for Large High-Resolution Solar Telescopes

    NASA Astrophysics Data System (ADS)

    Hammerschlag, Robert H.; Bettonvil, Felix C. M.; Jägers, Aswin P. L.; Sliepen, Guus

    2009-04-01

    Vacuum solar telescopes solve the problem of image deterioration inside the telescope due to refractive index fluctuations of the air heated by the solar light. However, such telescopes have a practical diameter limit somewhat over 1 m. The Dutch Open Telescope (DOT) was the pioneering demonstrator of the open-telescope technology without need of vacuum, now pursued in the German GREGOR. Important ingredients for this technology are primary beam completely open to natural wind flow, stiff but still open design by principal stiff overall geometries in combination with carefully designed joints and completely open-foldable dome constructions based on tensioned strong cloth. Further developments to large sizes are made within the framework of the design study for a European Solar Telescope (EST).

  8. A large-area gamma-ray imaging telescope system

    NASA Technical Reports Server (NTRS)

    Koch, D. G.

    1983-01-01

    The concept definition of using the External Tank (ET) of the Space Shuttle as the basis for constructing a large area gamma ray imaging telescope in space is detailed. The telescope will be used to locate and study cosmic sources of gamma rays of energy greater than 100 MeV. Both the telescope properties and the means whereby an ET is used for this purpose are described. A parallel is drawn between those systems that would be common to both a Space Station and this ET application. In addition, those systems necessary for support of the telescope can form the basis for using the ET as part of the Space Station. The major conclusions of this concept definition are that the ET is ideal for making into a gamma ray telescope, and that this telescope will provide a substantial increase in collecting area.

  9. Large fully retractable telescope enclosures still closable in strong wind

    NASA Astrophysics Data System (ADS)

    Bettonvil, Felix C. M.; Hammerschlag, Robert H.; Jägers, Aswin P. L.; Sliepen, Guus

    2008-07-01

    Two prototypes of fully retractable enclosures with diameters of 7 and 9 m have been built for the high-resolution solar telescopes DOT (Dutch Open Telescope) and GREGOR, both located at the Canary Islands. These enclosures protect the instruments for bad weather and are fully open when the telescopes are in operation. The telescopes and enclosures also operate in hard wind. The prototypes are based on tensioned membrane between movable but stiff bows, which fold together to a ring when opened. The height of the ring is small. The prototypes already survived several storms, with often snow and ice, without any damage, including hurricane Delta with wind speeds up to 68 m/s. The enclosures can still be closed and opened with wind speeds of 20 m/s without any problems or restrictions. The DOT successfully demonstrated the open, wind-flushing concept for astronomical telescopes. It is now widely recognized that also large future telescopes benefit from wind-flushing and retractable enclosures. These telescopes require enclosures with diameters of 30 m until roughly 100 m, the largest sizes for the ELTs (Extreme Large Telescopes), which will be built in the near future. We discuss developments and required technology for the realization of these large sizes.

  10. Wavefront Reconstruction Methods for a Natural Guide Star Adaptive Optics Application to the Keck Telescope

    NASA Technical Reports Server (NTRS)

    Milman, M.; Needels, L.; Redding, D.

    1994-01-01

    Keck telescope is planning to utilize adaptive optics technology to improve the resolution of the instrument. Telescopes operating in the atmosphere are limited by the seeing conditions at the telescope observational site.

  11. World Atlas of large optical telescopes (second edition)

    NASA Technical Reports Server (NTRS)

    Meszaros, S. P.

    1986-01-01

    By early 1986 there will be over 120 large optical telescopes in the world engaged in astronomical research with mirror or lens diameters of one meter (39-inches) and larger. This atlas gives information on these telescopes and shows their observatory sites on continent sized maps. Also shown are observatory locations considered suitable for the construction of future large telescopes. Of the 126 major telescopes listed in this atlas, 101 are situated in the Northern Hemisphere and 25 are located in the Southern Hemisphere. The totals by regions are as follows: Europe (excluding the USSR), 30; Soviet Union, 9; Asia (excluding the USSR), 5; Africa, 9; Australia, 6; The Pacific, 4 (all on Hawaii); South America, 17; North America, 46 (the continental US has 38 of these). In all, the United States has 42 of the world's major telescopes on its territory (continental US plus Hawaii) making it by far the leading nation in astronomical instrumentation.

  12. Astronomers, Congress, and the Large Space Telescope

    NASA Astrophysics Data System (ADS)

    Hanle, P. A.

    1985-04-01

    The Hubble Space Telescope (HST) project was initiated near the end of the Apollo program and immediately encountered fiscal contraints. Planned as a long-term facility, the HST had to be continually justified to the public, astronomers and Congress from 1973 onward. Budgetary restraints caused design reductions which for a while threatened the practicality of the HST and changed it from a pressurized, manned unit to an automatic mode, teleoperated, intermittently visited spacecraft. It is noted that numerous exaggerations were made of both the power of the HST for scientific research and the total support of the astronomical community during promotion of the HST program, although the HST is the most powerful visual wavelength telescope ever to be built due to its unique operating environment. NASA's consistent and steadily more detailed definitions of the design features and missions of the HST proved to be a decisive factor in repeated requests for information by funding committees who were deliberating in the presence of severe fiscal difficulties.

  13. Limits on Lyot coronagraphy with AEOS adaptive optics telescope

    NASA Astrophysics Data System (ADS)

    Sivaramakrishnan, A.; Makidon, R. B.; Lloyd, J. P.; Oppenheimer, B. R.; Graham, J. R.; Kalas, P. G.; Macintosh, B. A.; Max, C. E.; Baudoz, P.; Kuhn, J.; Potter, D.

    2001-05-01

    The 3.6m Air Force Electo-Optical System telescope is the most advanced adaptive optics (AO) system available to the astronomical community. Its 941-channel AO system feeds several stable instrument platforms at a very slow Cassegrain focus. Its small secondary obscuration makes it ideal for AO coronagraphy. We present estimates of current and theoretical limits on dynamic range using a diffraction-limited Lyot coronagraph optimized for the 3.6m AEOS telescope. We incorporate both the effects of imperfect AO correction of the wavefront and telescope guiding errors in our simulations. We calculate limits on faint companion detection (in the H-band) for this system at separations between 0.36 and 1.3 arcseconds.

  14. Design of optical systems for large space telescopes

    NASA Astrophysics Data System (ADS)

    Malamed, Evgeny R.; Sokolsky, M. N.

    1995-09-01

    On the basis of long-term experience of LOMO PLC in creating large optical systems for ground and space telescopes, with diameter of primary mirror from 1 to 6 meters, the following issues should be considered: principles of constructing optical systems for space telescopes and selecting their optimum design in respect of dimensions/mass and performance criteria; ensuring the fulfillment of image quality requirements in the process of manufacturing optical systems for controlling ground telescope elements in operating conditions; providing automatic adjustment of telescope secondary mirror, automatic focusing, interferometric control of image quality by means of stellar interferometer with radial shift and internal control with Gartman's test. Description of space telescope equipped with primary mirror of diameter 1.5 m, manufactured in LOMO PLC, is given.

  15. Innovative telescope architectures for future large space observatories

    NASA Astrophysics Data System (ADS)

    Polidan, Ronald S.; Breckinridge, James B.; Lillie, Charles F.; MacEwen, Howard A.; Flannery, Martin R.; Dailey, Dean R.

    2016-10-01

    Over the past few years, we have developed a concept for an evolvable space telescope (EST) that is assembled on orbit in three stages, growing from a 4×12-m telescope in Stage 1, to a 12-m filled aperture in Stage 2, and then to a 20-m filled aperture in Stage 3. Stage 1 is launched as a fully functional telescope and begins gathering science data immediately after checkout on orbit. This observatory is then periodically augmented in space with additional mirror segments, structures, and newer instruments to evolve the telescope over the years to a 20-m space telescope. We discuss the EST architecture, the motivation for this approach, and the benefits it provides over current approaches to building and maintaining large space observatories.

  16. Gamma Large Area Silicon Telescope (GLAST)

    SciTech Connect

    Godfrey, G.L.

    1993-11-01

    The recent discoveries and excitement generated by EGRET have prompted an investigation into modern technologies ultimately leading to the next generation space-based gamma ray telescope. The goal is to design a detector that will increase the data acquisition rate by almost two orders of magnitude beyond EGRET, while at the same time improving on the angular resolution, the energy measurement of reconstructed gamma rays, and the triggering capability of the instrument. The GLAST proposal is based on the assertion that silicon particle detectors are the technology of choice for space application: no consumables, no gas volume, robust (versus fragile), long lived, and self triggering. The GLAST detector is roughly modeled after EGRET in that a tracking module precedes a calorimeter. The GLAST Tracker has planes of thin radiatior interspersed with planes of crossed-strip (x,y) 300-{mu}m-pitch silicon detectors to measure the coordinates of converted electron-positron pairs. The gap between the layers ({approximately}5 cm) provides a lever arm in track fitting resulting in an angular resolution of 0.1{degree} at high energy (the low energy angular resolution at 100 MeV would be about 2{degree}, limited by multiple scattering). A possible GLAST calorimeter is made of a mosaic of Csl crystals of order 10 r.l. in depth, with silicon photodiodes readout. The increased depth of the GLAST calorimeter over EGRET`s extends the energy range to about 300 GeV.

  17. Eyeglass: A Very Large Aperture Diffractive Space Telescope

    SciTech Connect

    Hyde, R; Dixit, S; Weisberg, A; Rushford, M

    2002-07-29

    Eyeglass is a very large aperture (25-100 meter) space telescope consisting of two distinct spacecraft, separated in space by several kilometers. A diffractive lens provides the telescope's large aperture, and a separate, much smaller, space telescope serves as its mobile eyepiece. Use of a transmissive diffractive lens solves two basic problems associated with very large aperture space telescopes; it is inherently fieldable (lightweight and flat, hence packagable and deployable) and virtually eliminates the traditional, very tight, surface shape tolerances faced by reflecting apertures. The potential drawback to use of a diffractive primary (very narrow spectral bandwidth) is eliminated by corrective optics in the telescope's eyepiece. The Eyeglass can provide diffraction-limited imaging with either single-band, multiband, or continuous spectral coverage. Broadband diffractive telescopes have been built at LLNL and have demonstrated diffraction-limited performance over a 40% spectral bandwidth (0.48-0.72 {micro}m). As one approach to package a large aperture for launch, a foldable lens has been built and demonstrated. A 75 cm aperture diffractive lens was constructed from 6 panels of 1 m thick silica; it achieved diffraction-limited performance both before and after folding. This multiple panel, folding lens, approach is currently being scaled-up at LLNL. We are building a 5 meter aperture foldable lens, involving 72 panels of 700 {micro}m thick glass sheets, diffractively patterned to operate as coherent f/50 lens.

  18. Lightweight optical barrel assembly structures for large deployable space telescopes

    NASA Astrophysics Data System (ADS)

    Warren, Peter A.; Silver, Mark J.; Dobson, Benjamin J.

    2009-08-01

    Future space based telescopes will need apertures and focal lengths that exceed the dimensions of the launch vehicle shroud. In addition to deploying the primary mirror and secondary mirror support structure, these large telescopes must also deploy the stray light and thermal barriers needed to ensure proper telescope performance. The authors present a deployable light and thermal optical barrel assembly approach for a very large telescope with a variable sun angle and fast slew rate. The Strain Energy Deployable Optical Barrel Assembly (SEDOBA) uses elastic composite hinges to power the deployment of a hierarchical truss structure that supports the thermal and stray light shroud material that form the overall system. The paper describes the overall design approach, the key component technologies, and the design and preliminary testing of a self deploying scale model prototype.

  19. Advanced Mirror Technology Development (AMTD) for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2013-01-01

    Accomplishments include: Assembled outstanding team from academia, industry and government with expertise in science and space telescope engineering. Derived engineering specifications for monolithic primary mirror from science measurement needs & implementation constraints. Pursuing long-term strategy to mature technologies necessary to enable future large aperture space telescopes. Successfully demonstrated capability to make 0.5 m deep mirror substrate and polish it to UVOIR traceable figure specification.

  20. Adaptive optics at the Subaru telescope: current capabilities and development

    NASA Astrophysics Data System (ADS)

    Guyon, Olivier; Hayano, Yutaka; Tamura, Motohide; Kudo, Tomoyuki; Oya, Shin; Minowa, Yosuke; Lai, Olivier; Jovanovic, Nemanja; Takato, Naruhisa; Kasdin, Jeremy; Groff, Tyler; Hayashi, Masahiko; Arimoto, Nobuo; Takami, Hideki; Bradley, Colin; Sugai, Hajime; Perrin, Guy; Tuthill, Peter; Mazin, Ben

    2014-08-01

    Current AO observations rely heavily on the AO188 instrument, a 188-elements system that can operate in natural or laser guide star (LGS) mode, and delivers diffraction-limited images in near-IR. In its LGS mode, laser light is transported from the solid state laser to the launch telescope by a single mode fiber. AO188 can feed several instruments: the infrared camera and spectrograph (IRCS), a high contrast imaging instrument (HiCIAO) or an optical integral field spectrograph (Kyoto-3DII). Adaptive optics development in support of exoplanet observations has been and continues to be very active. The Subaru Coronagraphic Extreme-AO (SCExAO) system, which combines extreme-AO correction with advanced coronagraphy, is in the commissioning phase, and will greatly increase Subaru Telescope's ability to image and study exoplanets. SCExAO currently feeds light to HiCIAO, and will soon be combined with the CHARIS integral field spectrograph and the fast frame MKIDs exoplanet camera, which have both been specifically designed for high contrast imaging. SCExAO also feeds two visible-light single pupil interferometers: VAMPIRES and FIRST. In parallel to these direct imaging activities, a near-IR high precision spectrograph (IRD) is under development for observing exoplanets with the radial velocity technique. Wide-field adaptive optics techniques are also being pursued. The RAVEN multi-object adaptive optics instrument was installed on Subaru telescope in early 2014. Subaru Telescope is also planning wide field imaging with ground-layer AO with the ULTIMATE-Subaru project.

  1. Image Reconstruction Using Large Optical Telescopes.

    DTIC Science & Technology

    1982-02-15

    imaged the Pluto/Charon system, resolved a multiple QSO (quasar) and we have mapped and imaged asymmetries in the envelope around the supergiant star ...fringes for point source. 38 11.7. Interference fringes for binary star . 40 1I.8. Power spectrum of C Tau. 42 III.1. PG 1115+080. 50 111.2. Tracking...Dawe’s limit given above. An example of short exposure star photos, at very large image scale, is given in Figure 1.1. The overall size of these

  2. Inexpensive mount for a large millimeter-wavelength telescope.

    PubMed

    Padin, S

    2014-07-10

    A telescope mount with a single-point force support at the center of gravity of the primary mirror is proposed in order to eliminate much of the structure and cost of a large, millimeter-wavelength telescope. The single-point support gives repeatable thermal and gravitational deformation, so the surface of the primary can be controlled based on lookup tables for elevation and temperature. The new design is most appropriate for a survey telescope because locating the support above the vertex of the primary limits the range of motion of the mount to about 1 rad. A 30 m diameter, λ=850  μm telescope with the proposed mount is a factor of 4 lighter than a design with a conventional elevation-over-azimuth mount, and roughly half the cost.

  3. Early laser operations at the Large Binocular Telescope Observatory

    NASA Astrophysics Data System (ADS)

    Rahmer, Gustavo; Lefebvre, Michael; Christou, Julian; Raab, Walfried; Rabien, Sebastian; Ziegleder, Julian; Borelli, José L.; Gässler, Wolfgang

    2014-08-01

    ARGOS is the GLAO (Ground-Layer Adaptive Optics) Rayleigh-based LGS (Laser Guide Star) facility for the Large Binocular Telescope Observatory (LBTO). It is dedicated for observations with LUCI1 and LUCI2, LBTO's pair of NIR imagers and multi-object spectrographs. The system projects three laser beams from the back of each of the two secondary mirror units, which create two constellations circumscribed on circles of 2 arcmin radius with 120 degree spacing. Each of the six Nd:YAG lasers provides a beam of green (532nm) pulses at a rate of 10kHz with a power of 14W to 18W. We achieved first on-sky propagation on the night of November 5, 2013, and commissioning of the full system will take place during 2014. We present the initial results of laser operations at the observatory, including safety procedures and the required coordination with external agencies (FAA, Space Command, and Military Airspace Manager). We also describe our operational procedures and report on our experiences with aircraft spotters. Future plans for safer and more efficient aircraft monitoring and detection are discussed.

  4. Fast minimum variance wavefront reconstruction for extremely large telescopes.

    PubMed

    Thiébaut, Eric; Tallon, Michel

    2010-05-01

    We present what we believe to be a new algorithm, FRactal Iterative Method (FRiM), aiming at the reconstruction of the optical wavefront from measurements provided by a wavefront sensor. As our application is adaptive optics on extremely large telescopes, our algorithm was designed with speed and best quality in mind. The latter is achieved thanks to a regularization that enforces prior statistics. To solve the regularized problem, we use the conjugate gradient method, which takes advantage of the sparsity of the wavefront sensor model matrix and avoids the storage and inversion of a huge matrix. The prior covariance matrix is, however, non-sparse, and we derive a fractal approximation to the Karhunen-Loève basis thanks to which the regularization by Kolmogorov statistics can be computed in O(N) operations, with N being the number of phase samples to estimate. Finally, we propose an effective preconditioning that also scales as O(N) and yields the solution in five to ten conjugate gradient iterations for any N. The resulting algorithm is therefore O(N). As an example, for a 128 x 128 Shack-Hartmann wavefront sensor, the FRiM appears to be more than 100 times faster than the classical vector-matrix multiplication method.

  5. Disassembling and reintegration of large telescope primary mirror

    NASA Astrophysics Data System (ADS)

    Xu, Qi-rui; Fan, Bin; Zhang, Ming

    2014-09-01

    The success of the large telescope is largely linked to the excellent performance and reliability of the primary mirror. In order to maintain the quality of its reflective surface at the high expectations of astronomers, the primary mirror after almost two or three years of astronomical observations, needs to be removed and reinstalled for its cleaning and re-coating operation. There are a series of procedures such as the primary mirror cell dissembling from telescope, mirror handling, transportation, reintegration, alignment and so on. This paper will describe the experiences of disassembling and reintegration of large telescope primary mirror, taking a two meter grade primary mirror for example. As with all advanced and complex opto-mechanical systems, there has been the usual problems and trouble shooting.

  6. Sun avoidance strategies at the Large Millimeter Telescope

    NASA Astrophysics Data System (ADS)

    Souccar, Kamal; Smith, David R.; Schloerb, F. Peter; Wallace, Gary

    2016-07-01

    The Large Millimeter Telescope observatory is extending its night time operation to the day time. A sun avoidance strategy was therefore implemented in the control system in real-time to avoid excessive heating and damage to the secondary mirror and the prime focus. The LMT uses an "on-the-fly" trajectory generator that receives as input the target location of the telescope and in turn outputs a commanded position to the servo system. The sun avoidance strategy is also implemented "on-the-fly" where it intercepts the input to the trajectory generator and alters that input to avoid the sun. Two sun avoidance strategies were explored. The first strategy uses a potential field approach where the sun is represented as a high-potential obstacle in the telescope's workspace and the target location is represented as a low-potential goal. The potential field is repeatedly calculated as the sun and the telescope move and the telescope follows the induced force by this field. The second strategy is based on path planning using visibility graphs where the sun is represented as a polygonal obstacle and the telescope follows the shortest path from its actual position to the target location via the vertices of the sun's polygon. The visibility graph approach was chosen as the favorable strategy due to the efficiency of its algorithm and the simplicity of its computation.

  7. The Large Millimeter Telescope in the GLAST era

    SciTech Connect

    Carraminana, Alberto

    2007-07-12

    The Large Millimeter Telescope (LMT) was inaugurated on November 22, 2006. LMT will soon start commissioning and is expected to enter full science operations by 2008. With a 50m aperture, LMT will be the largest millimeter telescope and can become a powerful multiwavelength partner for GLAST. LMT will probe star formation at very high redshifts and can be used jointly with GLAST to uncover relativistic jet engines of flaring AGNs and GRBs. It will map with high resolution the distribution of molecular gas in nearby galaxies and in extended molecular clouds, providing an important input for gamma-ray emission models. These possibilities are a sample of how the Large Millimeter Telescope, working in a coordinated manner with GLAST, can become a powerful tool for high energy astrophysics.

  8. An overview of instrumentation for the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Wagner, R. Mark

    2008-07-01

    An overview of instrumentation for the Large Binocular Telescope is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (27' × 27') mosaic CCD imagers at the prime focus, and the Multi-Object Double Spectrograph (MODS), a pair of dual-beam blue-red optimized long-slit spectrographs mounted at the straight-through F/15 Gregorian focus incorporating multiple slit masks for multi-object spectroscopy over a 6 field and spectral resolutions of up to 8000. Infrared instrumentation includes the LBT Near-IR Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCIFER), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at a bent interior focal station and designed for seeing-limited (FOV: 4' × 4') imaging, long-slit spectroscopy, and multi-object spectroscopy utilizing cooled slit masks and diffraction limited (FOV: 0.5' × 0.5') imaging and long-slit spectroscopy. Strategic instruments under development for the remaining two combined focal stations include an interferometric cryogenic beam combiner with near-infrared and thermal-infrared instruments for Fizeau imaging and nulling interferometry (LBTI) and an optical bench near-infrared beam combiner utilizing multi-conjugate adaptive optics for high angular resolution and sensitivity (LINC-NIRVANA). In addition, a fiber-fed bench spectrograph (PEPSI) capable of ultra high resolution spectroscopy and spectropolarimetry (R = 40,000-300,000) will be available as a principal investigator instrument. The availability of all these instruments mounted simultaneously on the LBT permits unique science, flexible scheduling, and improved operational support.

  9. An overview of instrumentation for the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Wagner, R. Mark

    2010-07-01

    An overview of instrumentation for the Large Binocular Telescope is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (27 × 27) mosaic CCD imagers at the prime focus, and the Multi-Object Double Spectrograph (MODS), a pair of dual-beam blue-red optimized long-slit spectrographs mounted at the straight-through F/15 Gregorian focus incorporating multiple slit masks for multi-object spectroscopy over a 6 field and spectral resolutions of up to 8000. Infrared instrumentation includes the LBT Near-IR Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCIFER), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at a bent interior focal station and designed for seeing-limited (FOV: 4 × 4) imaging, long-slit spectroscopy, and multi-object spectroscopy utilizing cooled slit masks and diffraction limited (FOV: 0.5 × 0.5) imaging and long-slit spectroscopy. Strategic instruments under development for the remaining two combined focal stations include an interferometric cryogenic beam combiner with near-infrared and thermal-infrared instruments for Fizeau imaging and nulling interferometry (LBTI) and an optical bench near-infrared beam combiner utilizing multi-conjugate adaptive optics for high angular resolution and sensitivity (LINC-NIRVANA). In addition, a fiber-fed bench spectrograph (PEPSI) capable of ultra high resolution spectroscopy and spectropolarimetry (R = 40,000-300,000) will be available as a principal investigator instrument. The availability of all these instruments mounted simultaneously on the LBT permits unique science, flexible scheduling, and improved operational support. Over the past two years the LBC and the first LUCIFER instrument have been brought into routine scientific operation and MODS1 commissioning is set to begin in the fall of 2010.

  10. An overview of instrumentation for the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Wagner, R. Mark

    2004-09-01

    An overview of instrumentation for the Large Binocular Telescope is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (27'x 27') UB/VRI optimized mosaic CCD imagers at the prime focus, and the Multi-Object Double Spectrograph (MODS), a pair of dual-beam blue-red optimized long-slit spectrographs mounted at the straight-through F/15 Gregorian focus incorporating multiple slit masks for multi-object spectroscopy over a 6\\arcmin\\ field and spectral resolutions of up to 8000. Infrared instrumentation includes the LBT Near-IR Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCIFER), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at a bent interior focal station and designed for seeing-limited (FOV: 4'x 4') imaging, long-slit spectroscopy, and multi-object spectroscopy utilizing cooled slit masks and diffraction limited (FOV: 0'.5 x 0'.5) imaging and long-slit spectroscopy. Strategic instruments under development for the remaining two combined focal stations include an interferometric cryogenic beam combiner with near-infrared and thermal-infrared instruments for Fizeau imaging and nulling interferometry (LBTI) and an optical bench beam combiner with visible and near-infrared imagers utilizing multi-conjugate adaptive optics for high angular resolution and sensitivity (LINC/NIRVANA). In addition, a fiber-fed bench spectrograph (PEPSI) capable of ultra high resolution spectroscopy and spectropolarimetry (R = 40,000-300,000) will be available as a principal investigator instrument. The availability of all these instruments mounted simultaneously on the LBT permits unique science, flexible scheduling, and improved operational support.

  11. An overview of instrumentation for the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Wagner, R. Mark

    2006-06-01

    An overview of instrumentation for the Large Binocular Telescope is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (27' × 27') mosaic CCD imagers at the prime focus, and the Multi-Object Double Spectrograph (MODS), a pair of dual-beam blue-red optimized long-slit spectrographs mounted at the straight-through F/15 Gregorian focus incorporating multiple slit masks for multi-object spectroscopy over a 6' field and spectral resolutions of up to 8000. Infrared instrumentation includes the LBT Near-IR Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCIFER), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at a bent interior focal station and designed for seeing-limited (FOV: 4' × 4') imaging, long-slit spectroscopy, and multi-object spectroscopy utilizing cooled slit masks and diffraction limited (FOV: 0'.5 × 0'.5) imaging and long-slit spectroscopy. Strategic instruments under development for the remaining two combined focal stations include an interferometric cryogenic beam combiner with near-infrared and thermal-infrared instruments for Fizeau imaging and nulling interferometry (LBTI) and an optical bench near-infrared beam combiner utilizing multi-conjugate adaptive optics for high angular resolution and sensitivity (LINC-NIRVANA). In addition, a fiber-fed bench spectrograph (PEPSI) capable of ultra high resolution spectroscopy and spectropolarimetry (R = 40,000-300,000) will be available as a principal investigator instrument. The availability of all these instruments mounted simultaneously on the LBT permits unique science, flexible scheduling, and improved operational support.

  12. Performance predictions for the Keck telescope adaptive optics system

    SciTech Connect

    Gavel, D.T.; Olivier, S.S.

    1995-08-07

    The second Keck ten meter telescope (Keck-11) is slated to have an infrared-optimized adaptive optics system in the 1997--1998 time frame. This system will provide diffraction-limited images in the 1--3 micron region and the ability to use a diffraction-limited spectroscopy slit. The AO system is currently in the preliminary design phase and considerable analysis has been performed in order to predict its performance under various seeing conditions. In particular we have investigated the point-spread function, energy through a spectroscopy slit, crowded field contrast, object limiting magnitude, field of view, and sky coverage with natural and laser guide stars.

  13. ARTIST: Adaptable Radiative Transfer Innovations for Submillimeter Telescopes

    NASA Astrophysics Data System (ADS)

    Jørgensen, Jes; Brinch, Christian; Girart, Josep Miquel; Padovani, Marco; Frau, Pau; Schaaf, Reinhold; Kuiper, Rolf; Bertoldi, Frank; Hogerheijde, Michiel; Juhasz, Attila; Vlemmings, Wouter

    2014-02-01

    ARTIST is a suite of tools for comprehensive multi-dimensional radiative transfer calculations of dust and line emission, as well as their polarization, to help interpret observations from submillimeter telescopes. The ARTIST package consists of LIME, a radiative transfer code that uses adaptive gridding allowing simulations of sources with arbitrary multi-dimensional (1D, 2D, 3D) and time-dependent structures, thus ensuring rapid convergence; the DustPol and LinePol tools for modeling the polarization of the line and dust emission; and an interface run from Python scripts that manages the interaction between a general model library and LIME, and a graphical interface to simulate images.

  14. Self-Referencing Hartmann Test for Large-Aperture Telescopes

    NASA Technical Reports Server (NTRS)

    Korechoff, Robert P.; Oseas, Jeffrey M.

    2010-01-01

    A method is proposed for end-to-end, full aperture testing of large-aperture telescopes using an innovative variation of a Hartmann mask. This technique is practical for telescopes with primary mirrors tens of meters in diameter and of any design. Furthermore, it is applicable to the entire optical band (near IR, visible, ultraviolet), relatively insensitive to environmental perturbations, and is suitable for ambient laboratory as well as thermal-vacuum environments. The only restriction is that the telescope optical axis must be parallel to the local gravity vector during testing. The standard Hartmann test utilizes an array of pencil beams that are cut out of a well-corrected wavefront using a mask. The pencil beam array is expanded to fill the full aperture of the telescope. The detector plane of the telescope is translated back and forth along the optical axis in the vicinity of the nominal focal plane, and the centroid of each pencil beam image is recorded. Standard analytical techniques are then used to reconstruct the telescope wavefront from the centroid data. The expansion of the array of pencil beams is usually accomplished by double passing the beams through the telescope under test. However, this requires a well-corrected, autocollimation flat, the diameter or which is approximately equal to that of the telescope aperture. Thus, the standard Hartmann method does not scale well because of the difficulty and expense of building and mounting a well-corrected, large aperture flat. The innovation in the testing method proposed here is to replace the large aperture, well-corrected, monolithic autocollimation flat with an array of small-aperture mirrors. In addition to eliminating the need for a large optic, the surface figure requirement for the small mirrors is relaxed compared to that required of the large autocollimation flat. The key point that allows this method to work is that the small mirrors need to operate as a monolithic flat only with regard to

  15. Scientific Instrument Package for the large space telescope (SIP)

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The feasibility of a scientific instrument package (SIP) that will satisfy the requirements of the large space telescope was established. A reference configuration serving as a study model and data which will aid in the trade-off studies leading to the final design configuration are reported.

  16. Large space telescope, phase A. Volume 4: Scientific instrument package

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The design and characteristics of the scientific instrument package for the Large Space Telescope are discussed. The subjects include: (1) general scientific objectives, (2) package system analysis, (3) scientific instrumentation, (4) imaging photoelectric sensors, (5) environmental considerations, and (6) reliability and maintainability.

  17. Large space telescope, phase A. Volume 5: Support systems module

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development and characteristics of the support systems module for the Large Space Telescope are discussed. The following systems and described: (1) thermal control, (2) electrical, (3) communication and data landing, (4) attitude control system, and (5) structural features. Analyses of maintainability and reliability considerations are included.

  18. The scaling relationship between telescope cost and aperture size for very large telescopes

    NASA Technical Reports Server (NTRS)

    van Belle, Gerard T.; Meinel, Aden Baker; Meinel, Marjorie Pettit

    2004-01-01

    Cost data for ground-based telescopes of the last century are analyzed for trends in the relationship between aperture size and cost. We find that for apertures built prior to 1980, costs scaled as aperture size to the 2.8 power, which is consistent with the precious finding of Meinel (1978). After 1980, 'traditional' monolithic mirror telescope costs have scaled as aperture to the 2.5 power. The large multiple mirror telescopes built or in construction during this time period (Keck, LBT, GTC) appear to deviate from this relationship with significant cost savings as a result, although it is unclear what power law such structures follow. We discuss the implications of the current cost-aperture size data on the proposed large telescope projects of the next ten to twenty years. Structures that naturally tend towards the 2.0 power in the cost-aperture relationship will be the favorable choice for future extremely large apertures; out expectation is that space-based structures will ultimately gain economic advantage over ground-based ones.

  19. Fermi Large Area Telescope Bright Gamma-ray Source List

    SciTech Connect

    Abdo, Aous A.; Ackermann, M.; Ajello, M.; Atwood, W.B.; Axelsson, M.; Baldini, L.; Ballet, J.; Band, D.L.; Barbiellini, Guido; Bastieri, Denis; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bignami, G.F.; Bloom, Elliott D.; Bonamente, E.; Borgland, A.W.; Bregeon, J.; Brigida, M.; Bruel, P.; Burnett, Thompson H.; /more authors..

    2009-05-15

    Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope (Fermi) began a sky survey in August. The Large Area Telescope (LAT) on Fermi in three months produced a deeper and better resolved map of the {gamma}-ray sky than any previous space mission. We present here initial results for energies above 100 MeV for the 205 most significant (statistical significance greater than {approx}10{sigma}) {gamma}-ray sources in these data. These are the best characterized and best localized point-like (i.e., spatially unresolved) {gamma}-ray sources in the early mission data.

  20. Neptune and Titan Observed with Keck Telescope Adaptive Optics

    SciTech Connect

    Max, C.E.; Macintosh, B.A.; Gibbard, S.; Gavel, D.T.; Roe, H.; De Pater, I.; Ghez, A.M.; Acton, S.; Wizinowich, P.L.; Lai, O.

    2000-05-05

    The authors report on observations taken during engineering science validation time using the new adaptive optics system at the 10-m Keck II Telescope. They observe Neptune and Titan at near-infrared wavelengths. These objects are ideal for adaptive optics imaging because they are bright and small, yet have many diffraction-limited resolution elements across their disks. In addition Neptune and Titan have prominent physical features, some of which change markedly with time. They have observed infrared-bright storms on Neptune, and very low-albedo surface regions on Titan, Saturn's largest moon, Spatial resolution on Neptune and Titan was 0.05-0.06 and 0.04-0.05 arc sec, respectively.

  1. Neptune and Titan observed with Keck Telescope adaptive optics

    NASA Astrophysics Data System (ADS)

    Max, Claire E.; Macintosh, Bruce A.; Gibbard, Seran; Gavel, Donald T.; Roe, Henry; de Pater, Imke; Ghez, Andrea M.; Acton, Scott; Wizinowich, Peter L.; Lai, Olivier

    2000-07-01

    We report on observations taken during engineering science validation time using the new adaptive optics system at the 10-m Keck II Telescope. We observed Neptune and Titan at near- infrared wavelengths. These objects are ideal for adaptive optics imaging because they are bright and small, yet have many diffraction-limited resolution elements across their disks. In addition Neptune and Titan have prominent physical features, some of which change markedly with time. We have observed infrared-bright 'storms' on Neptune, and very low- albedo surface regions on Titan, Saturn's largest moon. Spatial resolution on Neptune and Titan was 0.05 - 0.06 and 0.04 - 0.05 arc sec, respectively.

  2. NST: Thermal Modeling for a Large Aperture Solar Telescope

    NASA Astrophysics Data System (ADS)

    Coulter, Roy

    2011-05-01

    Late in the 1990s the Dutch Open Telescope demonstrated that internal seeing in open, large aperture solar telescopes can be controlled by flushing air across the primary mirror and other telescope structures exposed to sunlight. In that system natural wind provides a uniform air temperature throughout the imaging volume, while efficiently sweeping heated air away from the optics and mechanical structure. Big Bear Solar Observatory's New Solar Telescope (NST) was designed to realize that same performance in an enclosed system by using both natural wind through the dome and forced air circulation around the primary mirror to provide the uniform air temperatures required within the telescope volume. The NST is housed in a conventional, ventilated dome with a circular opening, in place of the standard dome slit, that allows sunlight to fall only on an aperture stop and the primary mirror. The primary mirror is housed deep inside a cylindrical cell with only minimal openings in the side at the level of the mirror. To date, the forced air and cooling systems designed for the NST primary mirror have not been implemented, yet the telescope regularly produces solar images indicative of the absence of mirror seeing. Computational Fluid Dynamics (CFD) analysis of the NST primary mirror system along with measurements of air flows within the dome, around the telescope structure, and internal to the mirror cell are used to explain the origin of this seemingly incongruent result. The CFD analysis is also extended to hypothetical systems of various scales. We will discuss the results of these investigations.

  3. An overview of instrumentation for the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Wagner, R. Mark

    2012-09-01

    An overview of instrumentation for the Large Binocular Telescope (LBT) is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (27' x 27') mosaic CCD imagers at the prime focus, and the Multi-Object Double Spectrograph (MODS), a pair of dual-beam blue-red optimized long-slit spectrographs mounted at the left and right direct F/15 Gregorian foci incorporating multiple slit masks for multi-object spectroscopy over a 6' field and spectral resolutions of up to 2000. Infrared instrumentation includes the LBT Near-IR Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCI), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at the left and right front bent F/15 Gregorian foci and designed for seeing-limited (FOV: 4' × 4') imaging, long-slit spectroscopy, and multiobject spectroscopy utilizing cooled slit masks and diffraction limited (FOV: 0'.5 × 0'.5) imaging and long-slit spectroscopy. Strategic instruments under development that can utilize the full 23-m baseline of the LBT include an interferometric cryogenic beam combiner with near-infrared and thermal-infrared instruments for Fizeau imaging and nulling interferometry (LBTI) and an optical bench near-infrared beam combiner utilizing multi-conjugate adaptive optics for high angular resolution and sensitivity (LINC-NIRVANA). LBTI is currently undergoing commissioning on the LBT and utilizing the installed adaptive secondary mirrors in both single- sided and two-sided beam combination modes. In addition, a fiber-fed bench spectrograph (PEPSI) capable of ultra high resolution spectroscopy and spectropolarimetry (R = 40,000-300,000) will be available as a principal investigator instrument. Over the past four years the LBC pair, LUCI1, and MODS1 have been commissioned and are now scheduled for routine partner science observations. The delivery of both LUCI2 and MODS2 is anticipated before the end of 2012. The

  4. An Improved Wavefront Control Algorithm for Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Sidick, Erkin; Basinger, Scott A.; Redding, David C.

    2008-01-01

    Wavefront sensing and control is required throughout the mission lifecycle of large space telescopes such as James Webb Space Telescope (JWST). When an optic of such a telescope is controlled with both surface-deforming and rigid-body actuators, the sensitivity-matrix obtained from the exit pupil wavefront vector divided by the corresponding actuator command value can sometimes become singular due to difference in actuator types and in actuator command values. In this paper, we propose a simple approach for preventing a sensitivity-matrix from singularity. We also introduce a new "minimum-wavefront and optimal control compensator". It uses an optimal control gain matrix obtained by feeding back the actuator commands along with the measured or estimated wavefront phase information to the estimator, thus eliminating the actuator modes that are not observable in the wavefront sensing process.

  5. Wavelength dependence of star images formed by large ground-based telescopes including ELTs

    NASA Astrophysics Data System (ADS)

    McKechnie, T. Stewart

    2016-08-01

    Star image appearance in large ground-based telescopes is determined by the properties of the Optical Path Difference (OPD) fluctuation associated with the image-forming wave potions collected by the telescope aperture. The principal properties are the root mean square (rms) OPD fluctuation and the autocorrelation function of the OPD fluctuation. The OPD properties ultimately depend on the combined effects of turbulence in the atmospheric path, the fixed aberrations of the telescope and, if appropriate, the corrective effects of Adaptive Optics (AO). The equations given in this paper relating star image properties to the OPD properties (and also the inverse relations) apply to all large ground-based reflector telescopes, including ELTs. They apply equally to telescopes with and without AO. The OPD properties can be obtained directly from an image of an unresolved star. This image represents the intensity Point Spread Function (PSF) corresponding to the entire end-to-end imaging path. To obtain the full OPD information compliment, however, the image must be formed at a wavelength that delivers the most general type of star image: a core and halo image. Once the OPD properties have been obtained from such an image, the intensity PSF for the telescope/atmosphere/AO combination can immediately be calculated for any other wavelengths of interest in the extended optical wavelength range, 0.3 μm - 1000 μm. There are numerous applications for the mathematical relationships set out in this paper, including characterization of atmospheric paths, assessment of telescope/AO imaging performance, establishing wave front tolerances for ELTs and other large ground-based telescopes, and the rapid identification of sweetspot wavelength regions where highest resolution is achieved and star images attain maximum central intensity.

  6. Ideas for future large single dish radio telescopes

    NASA Astrophysics Data System (ADS)

    Kärcher, Hans J.; Baars, Jacob W. M.

    2014-07-01

    The existing large single dish radio telescopes of the 100m class (Effelsberg, Green Bank) were built in the 1970s and 1990s. With some active optics they work now down to 3 millimeter wavelength where the atmospheric quality of the site is also a limiting factor. Other smaller single dish telescopes (50m LMT Mexico, 30m IRAM Spain) are located higher and reach sub-millimeter quality, and the much smaller 12m antennas of the ALMA array reach at a very high site the Terahertz region. They use advanced technologies as carbon fiber structures and flexible body control. We review natural limits to telescope design and use the examples of a number of telescopes for an overview of the available state-of-the-art in design, engineering and technologies. Without considering the scientific justification we then offer suggestions to realize ultimate performance of huge single dish telescopes (up to 160m). We provide an outlook on design options, technological frontiers and cost estimates.

  7. Design of smart composite platforms for adaptive trust vector control and adaptive laser telescope for satellite applications

    NASA Astrophysics Data System (ADS)

    Ghasemi-Nejhad, Mehrdad N.

    2013-04-01

    This paper presents design of smart composite platforms for adaptive trust vector control (TVC) and adaptive laser telescope for satellite applications. To eliminate disturbances, the proposed adaptive TVC and telescope systems will be mounted on two analogous smart composite platform with simultaneous precision positioning (pointing) and vibration suppression (stabilizing), SPPVS, with micro-radian pointing resolution, and then mounted on a satellite in two different locations. The adaptive TVC system provides SPPVS with large tip-tilt to potentially eliminate the gimbals systems. The smart composite telescope will be mounted on a smart composite platform with SPPVS and then mounted on a satellite. The laser communication is intended for the Geosynchronous orbit. The high degree of directionality increases the security of the laser communication signal (as opposed to a diffused RF signal), but also requires sophisticated subsystems for transmission and acquisition. The shorter wavelength of the optical spectrum increases the data transmission rates, but laser systems require large amounts of power, which increases the mass and complexity of the supporting systems. In addition, the laser communication on the Geosynchronous orbit requires an accurate platform with SPPVS capabilities. Therefore, this work also addresses the design of an active composite platform to be used to simultaneously point and stabilize an intersatellite laser communication telescope with micro-radian pointing resolution. The telescope is a Cassegrain receiver that employs two mirrors, one convex (primary) and the other concave (secondary). The distance, as well as the horizontal and axial alignment of the mirrors, must be precisely maintained or else the optical properties of the system will be severely degraded. The alignment will also have to be maintained during thruster firings, which will require vibration suppression capabilities of the system as well. The innovative platform has been

  8. Resolving the Southern African Large Telescope's image quality problems

    NASA Astrophysics Data System (ADS)

    O'Donoghue, Darragh E.; Crause, Lisa A.; O'Connor, James; Strümpfer, Francois; Strydom, Ockert J.; Sass, Craig; Brink, Janus D.; Plessis, Charl du; Wiid, Eben; Love, Jonathan

    2013-08-01

    Images obtained with the Southern African Large Telescope (SALT) during its commissioning phase in 2006 showed degradation due to a large focus gradient, astigmatism, and higher order optical aberrations. An extensive forensic investigation exonerated the primary mirror and the science instruments before pointing to the mechanical interface between the telescope and the spherical aberration corrector, the complex optical subassembly which corrects the spherical aberration introduced by the 11-m primary mirror. Having diagnosed the problem, a detailed repair plan was formulated and implemented when the corrector was removed from the telescope in April 2009. The problematic interface was replaced, and the four aspheric mirrors were optically tested and re-aligned. Individual mirror surface figures were confirmed to meet specification, and a full system test after the re-alignment yielded a root mean square wavefront error of 0.15 waves. The corrector was reinstalled in August 2010 and aligned with respect to the payload and primary mirror. Subsequent on-sky tests revealed spurious signals being sent to the tracker by the auto-collimator, the instrument that maintains the alignment of the corrector with respect to the primary mirror. After rectifying this minor issue, the telescope yielded uniform 1.1 arcsec star images over the full 10-arcmin field of view.

  9. First-order design of off-axis reflective ophthalmic adaptive optics systems using afocal telescopes.

    PubMed

    Gómez-Vieyra, Armando; Dubra, Alfredo; Malacara-Hernández, Daniel; Williams, David R

    2009-10-12

    Expressions for minimal astigmatism in image and pupil planes in off-axis afocal reflective telescopes formed by pairs of spherical mirrors are presented. These formulae which are derived from the marginal ray fan equation can be used for designing laser cavities, spectrographs and adaptive optics retinal imaging systems. The use, range and validity of these formulae are limited by spherical aberration and coma for small and large angles respectively. This is discussed using examples from adaptive optics retinal imaging systems. The performance of the resulting optical designs are evaluated and compared against the configurations with minimal wavefront RMS, using the defocus-corrected wavefront RMS as a metric.

  10. Status report on the Large Binocular Telescope's ARGOS ground-layer AO system

    NASA Astrophysics Data System (ADS)

    Hart, M.; Rabien, S.; Busoni, L.; Barl, L.; Beckmann, U.; Bonaglia, M.; Boose, Y.; Borelli, J. L.; Bluemchen, T.; Carbonaro, L.; Connot, C.; Deysenroth, M.; Davies, R.; Durney, O.; Elberich, M.; Ertl, T.; Esposito, S.; Gaessler, W.; Gasho, V.; Gemperlein, H.; Hubbard, P.; Kanneganti, S.; Kulas, M.; Newman, K.; Noenickx, J.; Orban de Xivry, G.; Peter, D.; Quirrenbach, A.; Rademacher, M.; Schwab, C.; Storm, J.; Vaitheeswaran, V.; Weigelt, G.; Ziegleder, J.

    2011-10-01

    ARGOS, the laser-guided adaptive optics system for the Large Binocular Telescope (LBT), is now under construction at the telescope. By correcting atmospheric turbulence close to the telescope, the system is designed to deliver high resolution near infrared images over a field of 4 arc minute diameter. Each side of the LBT is being equipped with three Rayleigh laser guide stars derived from six 18 W pulsed green lasers and projected into two triangular constellations matching the size of the corrected field. The returning light is to be detected by wavefront sensors that are range gated within the seeing-limited depth of focus of the telescope. Wavefront correction will be introduced by the telescope's deformable secondary mirrors driven on the basis of the average wavefront errors computed from the respective guide star constellation. Measured atmospheric turbulence profiles from the site lead us to expect that by compensating the ground-layer turbulence, ARGOS will deliver median image quality of about 0.2 arc sec across the JHK bands. This will be exploited by a pair of multi-object near-IR spectrographs, LUCIFER1 and LUCIFER2, with 4 arc minute field already operating on the telescope. In future, ARGOS will also feed two interferometric imaging instruments, the LBT Interferometer operating in the thermal infrared, and LINC-NIRVANA, operating at visible and near infrared wavelengths. Together, these instruments will offer very broad spectral coverage at the diffraction limit of the LBT's combined aperture, 23 m in size.

  11. Extreme Adaptive Optics for the Thirty Meter Telescope

    SciTech Connect

    Macintosh, B; al., e

    2006-05-02

    Direct detection of extrasolar Jovian planets is a major scientific motivation for the construction of future extremely large telescopes such as the Thirty Meter Telescope (TMT). Such detection will require dedicated high-contrast AO systems. Since the properties of Jovian planets and their parent stars vary enormously between different populations, the instrument must be designed to meet specific scientific needs rather than a simple metric such as maximum Strehl ratio. We present a design for such an instrument, the Planet Formation Imager (PFI) for TMT. It has four key science missions. The first is the study of newly-formed planets on 5-10 AU scales in regions such as Taurus and Ophiucus--this requires very small inner working distances that are only possible with a 30m or larger telescope. The second is a robust census of extrasolar giant planets orbiting mature nearby stars. The third is detailed spectral characterization of the brightest extrasolar planets. The final targets are circumstellar dust disks, including Zodiacal light analogs in the inner parts of other solar systems. To achieve these, PFI combines advanced wavefront sensors, high-order MEMS deformable mirrors, a coronagraph optimized for a finely-segmented primary mirror, and an integral field spectrograph.

  12. Data Management at the Southern African Large Telescope

    NASA Astrophysics Data System (ADS)

    Crawford, Steve

    2015-12-01

    PySALT is the python/PyRAF-based data reduction and analysis pipeline for the Southern African Large Telescope (SALT), a modern 10m class telescope with a large user community consisting of 13 partner institutions. The suite of tools developed as part of PySALT include: (1) science quality reductions for the major operational modes of SALT include high-time resolution and spectroscopic reductions, (2) quick-look capabilities for the observers and real-time data delivery for the investigators, and (3) management of the data archive and regularly processing of SALT observations. In addition to presenting the overall framework, we also highlight some of the lessons learned since the start of SALT scientific observations in 2011.

  13. A large fiber sensor network for an acoustic neutrino telescope

    NASA Astrophysics Data System (ADS)

    Buis, Ernst-Jan; Doppenberg, Ed; Lahmann, Robert; Toet, Peter

    2017-03-01

    The scientific prospects of detecting neutrinos with an energy close or even higher than the GKZ cut-off energy has been discussed extensively in literature. It is clear that due to their expected low flux, the detection of these ultra-high energy neutrinos (Ev > 1018 eV) requires a telescope larger than 100 km3. Acoustic detection may provide a way to observe these ultra-high energy cosmic neutrinos, as sound that they induce in the deep sea when neutrinos lose their energy travels undisturbed for many kilometers. To realize a large scale acoustic neutrino telescope, dedicated technology must be developed that allows for a deep sea sensor network. Fiber optic hydrophone technology provides a promising means to establish a large scale sensor network [1] with the proper sensitivity to detect the small signals from the neutrino interactions.

  14. Adaptive Optics Imaging of Neptune with the W.M. Keck Telescope

    NASA Astrophysics Data System (ADS)

    Macintosh, B.; Max, C. E.; Roe, H.; Gibbard, S.; Gavel, D.; Acton, S.; Lai, O.; Wizinowich, P.; de Pater, I.; Ghez, A.; Baines, K.

    1999-09-01

    We present near-IR images of Neptune with a resolution of 0.05 arcseconds obtained with the new adaptive optics (AO) system at the 10-m W.M. Keck II telescope. The resolution and contrast of these images allows us to fit radiative transfer models to Neptune's clear atmosphere, completely uncontaminated by scattered light from bright storms or bands. We can measure for the first time the precise infrared spatial extent of storm features and calculate their reflectance in broad-band and methane-absorption near-IR bandpasses. The images show many bands and cloud features, and detect a bright southern-hemisphere complex that may be associated with a large dark spot similar to that seen by Voyager. These observations demonstrate that AO on an 8-10 meter telescope is a powerful new tool for studying objects in the outer solar system, surpassing the resolution of the NICMOS instrument on the Hubble Space Telescope by a factor of 2-4. This research was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract W-7405-ENG-48. It was supported in part by NASA grant NRA-97-OSS-04-98-053(R3281). The adaptive optics system on the Keck II telescope was funded by the W.M. Keck foundation under a grant to the California Association for Research in Astronomy, and by NASA.

  15. High Energy Astrophysics with the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Hays, Elizabeth

    2009-01-01

    This slide presentation reviews some of the findings of the Large Area Telescope (LAT) aboard the Fermi Observatory. It includes information about the LAT, and the Gamma-Ray Burst Monitor (GBM), detection of the quiet sun and the moon in gamma rays, Pulsars observed by the observatory, Globular Star Clusters, Active Galactic Nucleus, and Gamma-Ray Bursts, with specific information about GRB 080916C.

  16. Extremely Large Telescope Project Selected in ESFRI Roadmap

    NASA Astrophysics Data System (ADS)

    2006-10-01

    In its first Roadmap, the European Strategy Forum on Research Infrastructures (ESFRI) choose the European Extremely Large Telescope (ELT), for which ESO is presently developing a Reference Design, as one of the large scale projects to be conducted in astronomy, and the only one in optical astronomy. The aim of the ELT project is to build before the end of the next decade an optical/near-infrared telescope with a diameter in the 30-60m range. ESO PR Photo 40/06 The ESFRI Roadmap states: "Extremely Large Telescopes are seen world-wide as one of the highest priorities in ground-based astronomy. They will vastly advance astrophysical knowledge allowing detailed studies of inter alia planets around other stars, the first objects in the Universe, super-massive Black Holes, and the nature and distribution of the Dark Matter and Dark Energy which dominate the Universe. The European Extremely Large Telescope project will maintain and reinforce Europe's position at the forefront of astrophysical research." Said Catherine Cesarsky, Director General of ESO: "In 2004, the ESO Council mandated ESO to play a leading role in the development of an ELT for Europe's astronomers. To that end, ESO has undertaken conceptual studies for ELTs and is currently also leading a consortium of European institutes engaged in studying enabling technologies for such a telescope. The inclusion of the ELT in the ESFRI roadmap, together with the comprehensive preparatory work already done, paves the way for the next phase of this exciting project, the design phase." ESO is currently working, in close collaboration with the European astronomical community and the industry, on a baseline design for an Extremely Large Telescope. The plan is a telescope with a primary mirror between 30 and 60 metres in diameter and a financial envelope of about 750 m Euros. It aims at more than a factor ten improvement in overall performance compared to the current leader in ground based astronomy: the ESO Very Large

  17. The Large Binocular Telescope mount control system architecture

    NASA Astrophysics Data System (ADS)

    Ashby, David S.; McKenna, Dan; Brynnel, Joar G.; Sargent, Tom; Cox, Dan; Little, John; Powell, Keith; Holmberg, Gene

    2006-06-01

    The Large Binocular Telescope (LBT) features dual 8.4 m diameter mirrors in a common elevation-over-azimuth mount. The LBT moves in elevation on two large crescent-shaped C-rings that are supported by radial hydrostatic bearing pads located near the four corners of the rectangular azimuth frame. The azimuth frame, in turn, is supported by four hydrostatic bearing pads and uses hydrodynamic roller bearings for centering. Each axis is gear driven by four large electric motors. In addition to precision optical motor encoders, each axis is equipped with Farrand Inductosyn strip encoders which yield 0.005 arcsecond resolution. The telescope weighs 580 metric tons and is designed to track with 0.03 arcsecond or better servo precision under wind speeds as high as 24 km/hr. Though the telescope is still under construction, the Mount Control System (MCS) has been routinely exercised to achieve First Light. The authors present a description of the unique, DSP-based synchronous architecture of the MCS and its capabilities.

  18. Robust Optimal Adaptive Control Method with Large Adaptive Gain

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan T.

    2009-01-01

    In the presence of large uncertainties, a control system needs to be able to adapt rapidly to regain performance. Fast adaptation is referred to the implementation of adaptive control with a large adaptive gain to reduce the tracking error rapidly. However, a large adaptive gain can lead to high-frequency oscillations which can adversely affect robustness of an adaptive control law. A new adaptive control modification is presented that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. The modification is based on the minimization of the Y2 norm of the tracking error, which is formulated as an optimal control problem. The optimality condition is used to derive the modification using the gradient method. The optimal control modification results in a stable adaptation and allows a large adaptive gain to be used for better tracking while providing sufficient stability robustness. Simulations were conducted for a damaged generic transport aircraft with both standard adaptive control and the adaptive optimal control modification technique. The results demonstrate the effectiveness of the proposed modification in tracking a reference model while maintaining a sufficient time delay margin.

  19. Compact high-resolution spectrographs for large and extremely large telescopes: using the diffraction limit

    NASA Astrophysics Data System (ADS)

    Robertson, J. Gordon; Bland-Hawthorn, Joss

    2012-09-01

    As telescopes get larger, the size of a seeing-limited spectrograph for a given resolving power becomes larger also, and for ELTs the size will be so great that high resolution instruments of simple design will be infeasible. Solutions include adaptive optics (but not providing full correction for short wavelengths) or image slicers (which give feasible but still large instruments). Here we develop the solution proposed by Bland-Hawthorn and Horton: the use of diffraction-limited spectrographs which are compact even for high resolving power. Their use is made possible by the photonic lantern, which splits a multi-mode optical fiber into a number of single-mode fibers. We describe preliminary designs for such spectrographs, at a resolving power of R ~ 50,000. While they are small and use relatively simple optics, the challenges are to accommodate the longest possible fiber slit (hence maximum number of single-mode fibers in one spectrograph) and to accept the beam from each fiber at a focal ratio considerably faster than for most spectrograph collimators, while maintaining diffraction-limited imaging quality. It is possible to obtain excellent performance despite these challenges. We also briefly consider the number of such spectrographs required, which can be reduced by full or partial adaptive optics correction, and/or moving towards longer wavelengths.

  20. Cosmic Ray Studies with the Fermi Gamma-ray Space Telescope Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Thompson, David J.; Baldini, L.; Uchiyama, Y.

    2012-01-01

    The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope provides both direct and indirect measurements of galactic cosmic rays (CR). The LAT high-statistics observations of the 7 GeV - 1 TeV electron plus positron spectrum and limits on spatial anisotropy constrain models for this cosmic-ray component. On a galactic scale, the LAT observations indicate that cosmic-ray sources may be more plentiful in the outer Galaxy than expected or that the scale height of the cosmic-ray diffusive halo is larger than conventional models. Production of cosmic rays in supernova remnants (SNR) is supported by the LAT gamma-ray studies of several of these, both young SNR and those interacting with molecular clouds.

  1. Cosmic Ray Studies with the Fermi Gamma-ray Space Telescope Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Baldini, L.; Uchiyama, Y.

    2011-01-01

    The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope provides both direct and indirect measurements of Galactic cosmic rays (CR). The LAT high-statistics observations of the 7 GeV - 1 TcV electron plus positron spectrum and limits on spatial anisotropy constrain models for this cosmic-ray component. On a Galactic scale, the LAT observations indicate that cosmic-ray sources may be more plentiful in the outer Galaxy than expected or that the scale height of the cosmic-ray diffusive halo is larger than conventional models. Production of cosmic rays in supernova remnants (SNR) is supported by the LAT gamma-ray studies of several of these, both young SNR and those interacting with molecular clouds.

  2. Large thin adaptive x-ray mirrors

    NASA Astrophysics Data System (ADS)

    Doel, Peter; Atkins, Carolyn; Thompson, Samantha; Brooks, David; Yao, Jun; Feldman, Charlotte; Willingale, Richard; Button, Tim; Zhang, Dou; James, Ady

    2007-09-01

    This paper describes the progress made in a proof of concept study and recent results of a research program into large active x-ray mirrors that is part of the UK Smart X-ray Optics project. The ultimate aim is to apply the techniques of active/adaptive optics to the next generation of nested shell astronomical X-ray space telescopes. A variety of deformable mirror technologies are currently available, the most promising of which for active X-ray mirrors are probably unimorph and bimorph piezoelectric mirrors. In this type of mirror one or more sheets of piezoelectric material are bonded to or coated with a passive reflective layer. On the back or between the piezoceramic layer/layers are series of electrodes. Application of an electric field causes the piezoelectric material to undergo local deformation thus changing the mirror shape. Starting in 2005 a proof of concept active mirror research program has been undertaken. This work included modelling and development of actively controlled thin shell mirrors. Finite element models of piezo-electric actuated mirrors have been developed and verified against experimental test systems. This has included the modelling and test of piezo-electric hexagonal unimorph segments. Various actuator types and low shrinkage conductive bonding methods have been investigated and laboratory tests of the use of piezo-electric actuators to adjust the form of an XMM-Newton space telescope engineering model mirror shell have been conducted and show that movement of the optics at the required level is achievable. Promising technological approaches have been identified including moulded piezo-ceramics and piezo-electrics fibre bundles.

  3. New 50-m-class single-dish telescope: Large Submillimeter Telescope (LST)

    NASA Astrophysics Data System (ADS)

    Kawabe, Ryohei; Kohno, Kotaro; Tamura, Yoichi; Takekoshi, Tatsuya; Oshima, Tai; Ishii, Shun

    2016-08-01

    We report on a plan to construct a 50-m-class single-dish telescope, the Large Submillimeter Telescope (LST). The conceptual design and key science behind the LST are presented, together with its tentative specifications. This telescope is optimized for wide-area imaging and spectroscopic surveys in the 70-420 GHz frequency range, which spans the main atmospheric windows at millimeter and submillimeter wavelengths for good observation sites such as the Atacama Large Millimeter/submillimeter Array (ALMA) site in Chile. We also target observations at higher frequencies of up to 1 THz, using an inner high-precision surface. Active surface control is required in order to correct gravitational and thermal deformations of the surface, and will be useful for correction of the wind-load deformation. The LST will facilitate new discovery spaces such as wide-field imaging with both continuum and spectral lines, along with new developments for time-domain science. Through exploitation of its synergy with ALMA and other telescopes, the LST will contribute to research on a wide range of topics in the fields of astronomy and astrophysics, e.g., astrochemistry, star formation in our Galaxy and galaxies, the evolution of galaxy clusters via the Sunyaev-Zel'dovich (SZ) effect, the search for transients such as γ-ray burst reverse shocks produced during the epoch of re-ionization, electromagnetic follow up of detected gravitational wave sources, and examination of general relativity in the vicinity of super massive black holes via submillimeter very-long-baseline interferometry (VLBI).

  4. Spectrographs and Large Telescopes: A Study of Instrumentation

    NASA Astrophysics Data System (ADS)

    Fica, Haley Diane; Crane, Jeffrey D.; Uomoto, Alan K.; Hare, Tyson

    2017-01-01

    It is a truth universally acknowledged, that a telescope in possession of a large aperture, must be in want of a high resolution spectrograph. Subsystems of these instruments require testing and upgrading to ensure that they can continue to be scientifically productive and usher in a new era of astronomical research. The Planet Finder Spectrograph (PFS) and Magellan Inamori Kyocera Echelle (MIKE), both on the Magellan II Clay telescope at Las Campanas Observatory, and the Giant Magellan Telescope (GMT) Consortium Large Earth Finder (G-CLEF) are examples of such instruments. Bluer flat field lamps were designed for PFS and MIKE to replace lamps no longer available in order to ensure continued, efficient functionality. These newly designed lamps will result in better flat fielding and calibration of data, and thus result in increased reduction of instrument noise. When it is built and installed in 2022, G-CLEF will be be fed by a tertiary mirror on the GMT. Stepper motors attached to the back of this mirror will be used to correct misalignments in the optical relay system. These motors were characterized to ensure that they function as expected to an accuracy of a few microns. These projects incorporate several key aspects of astronomical instrumentation: designing, building, and testing.

  5. The GLAST Large Area Telescope Detector Performance Monitoring

    SciTech Connect

    Borgland, A. W.; Charles, E.

    2007-07-12

    The Large Area Telescope (LAT) is one of two instruments on board the Gamma-ray Large Area Telescope (GLAST), the next generation high energy gamma-ray space telescope. The LAT contains sixteen identical towers in a four-by-four grid. Each tower contains a silicon-strip tracker and a CsI calorimeter that together will give the incident direction and energy of the pair-converting photon in the energy range 20 MeV - 300 GeV. In addition, the instrument is covered by a finely segmented Anti-Coincidence Detector (ACD) to reject charged particle background. Altogether, the LAT contains more than 864k channels in the trackers, 1536 CsI crystals and 97 ACD plastic scintillator tiles and ribbons. Here we detail some of the strategies and methods for how we are planning to monitor the instrument performance on orbit. It builds on the extensive experience gained from Integration and Test and Commissioning of the instrument on ground.

  6. The GLAST Large Area Telescope Detector Performance Monitoring

    SciTech Connect

    Borgland, A.W.; Charles, E.; /SLAC

    2007-10-16

    The Large Area Telescope (LAT) is one of two instruments on board the Gamma-ray Large Area Telescope (GLAST), the next generation high energy gamma-ray space telescope. The LAT contains sixteen identical towers in a four-by-four grid. Each tower contains a silicon-strip tracker and a CsI calorimeter that together will give the incident direction and energy of the pair-converting photon in the energy range 20 MeV - 300 GeV. In addition, the instrument is covered by a finely segmented Anti-Coincidence Detector (ACD) to reject charged particle background. Altogether, the LAT contains more than 864k channels in the trackers, 1536 CsI crystals and 97 ACD plastic scintillator tiles and ribbons. Here we detail some of the strategies and methods for how we are planning to monitor the instrument performance on orbit. It builds on the extensive experience gained from Integration & Test and Commissioning of the instrument on ground.

  7. The GLAST Large Area Telescope Detector Performance Monitoring

    NASA Astrophysics Data System (ADS)

    Borgland, A. W.; Charles, E.

    2007-07-01

    The Large Area Telescope (LAT) is one of two instruments on board the Gamma-ray Large Area Telescope (GLAST), the next generation high energy gamma-ray space telescope. The LAT contains sixteen identical towers in a four-by-four grid. Each tower contains a silicon-strip tracker and a CsI calorimeter that together will give the incident direction and energy of the pair-converting photon in the energy range 20 MeV - 300 GeV. In addition, the instrument is covered by a finely segmented Anti-Coincidence Detector (ACD) to reject charged particle background. Altogether, the LAT contains more than 864k channels in the trackers, 1536 CsI crystals and 97 ACD plastic scintillator tiles and ribbons. Here we detail some of the strategies and methods for how we are planning to monitor the instrument performance on orbit. It builds on the extensive experience gained from Integration & Test and Commissioning of the instrument on ground.

  8. Thermal imaging of the Large Millimeter Telescope structure

    NASA Astrophysics Data System (ADS)

    Smith, David R.

    2010-07-01

    A dominant problem for large, high precision telescopes is the deformation due to temperature changes in the structure. Even for active surface designs such as the Large Millimeter Telescope/Gran Telescopio Milimetrico (LMT), accurate knowledge of the temperature distribution in the structure is necessary in order to adjust the primary reflector panels and make pointing corrections. The design of thermal management system of the LMT consists of a fully-cladded structure, a forced ventilation system, and a collection of temperature sensors distributed throughout the telescope. During the design, both steady-state and dynamic thermal models were developed to predict the thermal behavior. Additionally, some thermal measurements were taken during construction, before the cladding was installed. Since the structure is now completely enclosed with insulating cladding, it is an excellent candidate for thermal imaging at this stage of the commissioning. Thermal images of the structure are presented, showing the actual temperature distribution of the LMT alidade structure and reflector. The images are taken from a consistent set of positions to show the how the structural temperature distribution evolves over day and night conditions.

  9. Large space telescope, phase A. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Phase A study of the Large Space Telescope (LST) is reported. The study defines an LST concept based on the broad mission guidelines provided by the Office of Space Science (OSS), the scientific requirements developed by OSS with the scientific community, and an understanding of long range NASA planning current at the time the study was performed. The LST is an unmanned astronomical observatory facility, consisting of an optical telescope assembly (OTA), scientific instrument package (SIP), and a support systems module (SSM). The report consists of five volumes. The report describes the constraints and trade off analyses that were performed to arrive at a reference design for each system and for the overall LST configuration. A low cost design approach was followed in the Phase A study. This resulted in the use of standard spacecraft hardware, the provision for maintenance at the black box level, growth potential in systems designs, and the sharing of shuttle maintenance flights with other payloads.

  10. Cloud Structures on Neptune Observed with Keck Telescope Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Max, C. E.; Macintosh, B. A.; Gibbard, S. G.; Gavel, D. T.; Roe, H. G.; de Pater, I.; Ghez, A. M.; Acton, D. S.; Lai, O.; Stomski, P.; Wizinowich, P. L.

    2003-01-01

    We report on observations obtained with the adaptive optics system at the 10 m Keck II Telescope during engineering validation and early science observing time for the adaptive optics system. We observed Neptune at near-infrared wavelengths. Angular resolution was 0.05"-0.06", corresponding to a spatial scale of approximately 1000 km at Neptune. We discuss the latitudinal structure of circumferential cloud bands and of compact infrared-bright features seen in the southern hemisphere, as well as their variation with wavelength. We determine the values of I/F (proportional to the ratio of reflected intensity to incident solar flux) in the J and H infrared-wavelength bands, including narrowband filters where there is strong methane absorption. We use the I/F values inside and outside of methane bands to estimate the altitude of clouds responsible for the brightest compact features in the infrared. Our data show that, on two of our four observing dates, the brightest region on Neptune contained highly reflective haze layers located below the tropopause but not deeper than a few bars.

  11. Layer-oriented adaptive optics for solar telescopes.

    PubMed

    Kellerer, Aglaé

    2012-08-10

    First multiconjugate adaptive-optical (MCAO) systems are currently being installed on solar telescopes. The aim of these systems is to increase the corrected field of view with respect to conventional adaptive optics. However, this first generation is based on a star-oriented approach, and it is then difficult to increase the size of the field of view beyond 60-80 arc sec in diameter. We propose to implement the layer-oriented approach in solar MCAO systems by use of wide-field Shack-Hartmann wavefront sensors conjugated to the strongest turbulent layers. The wavefront distortions are averaged over a wide field: the signal from distant turbulence is attenuated and the tomographic reconstruction is thus done optically. The system consists of independent correction loops, which only need to account for local turbulence: the subapertures can be enlarged and the correction frequency reduced. Most importantly, a star-oriented MCAO system becomes more complex with increasing field size, while the layer-oriented approach benefits from larger fields and will therefore be an attractive solution for the future generation of solar MCAO systems.

  12. The feasibility of large refracting telescopes for solar coronal research

    NASA Astrophysics Data System (ADS)

    Nelson, Peter G.; Tomczyk, Steven; Elmore, David F.; Kolinski, Donald J.

    2008-07-01

    Measuring magnetic fields in the solar corona requires a large aperture telescope with exceptionally low levels of scattered light. For internally-occulted coronagraphs the main source is scattering from dust or microroughness on the primary lens or mirror. We show refracting primaries offer significantly lower levels for both sources. To observe magnetic fields in the solar corona with scientifically interesting spatial and temporal resolutions, a 1 meter aperture or larger is required. For a long time such large-scale refractors have been deemed impractical or impossible to construct due to gravitational deformation of the lens. We present the results of finite-element and optical analyses of the gravitational deformation, stress-induced birefringence, and absorptive heating of a (see manuscript)1.5 meter f/5 fused silica lens. These studies demonstrate the traditional objections to large refractors are unfounded and large refracting primaries have unique capabilities.

  13. BLAST: The Balloon-Borne Large Aperture Submillimeter Telescope

    NASA Technical Reports Server (NTRS)

    Devlin, Mark; Ade, Peter; Bock, Jamie; Dicker, Simon; Griffin, Matt; Gunderson, Josh; Halpern, Mark; Hargrave, Peter; Hughes, David; Klein, Jeff

    2004-01-01

    BLAST is the Balloon-borne Large-Aperture Sub-millimeter Telescope. It will fly from a Long Duration Balloon (LDB) platform from Antarctica. The telescope design incorporates a 2 m primary mirror with large-format bolometer arrays operating at 250, 350 and 500 microns. By providing the first sensitive large-area (10 sq. deg.) sub-mm surveys at these wavelengths, BLAST will address some of the most important galactic and cosmological questions regarding the formation and evolution of stars, galaxies and clusters. Galactic and extragalactic BLAST surveys will: (1) identify large numbers of high-redshift galaxies; (2) measure photometric redshifts, rest-frame FIR luminosities and star formation rates thereby constraining the evolutionary history of the galaxies that produce the FIR and sub-mm background; (3) measure cold pre-stellar sources associated with the earliest stages of star and planet formation; (4) make high-resolution maps of diffuse galactic emission over a wide range of galactic latitudes. In addition to achieving the above scientific goals, the exciting legacy of the BLAST LDB experiment will be a catalogue of 3000-5000 extragalactic sub-mm sources and a 100 sq. deg. sub-mm galactic plane survey. Multi-frequency follow-up observations from SIRTF, ASTRO-F, and Herschel, together with spectroscopic observations and sub-arcsecond imaging from ALMA are essential to understand the physical nature of the BLAST sources.

  14. Lessons learned with the Active Phasing Experiment: comparison of four optical phasing sensors on a segmented Very Large Telescope

    NASA Astrophysics Data System (ADS)

    Gonte, F.; Surdej, I.

    The adaptive optics capabilities are strongly limited by the quality of the phasing of the primary mirror of the extremely large telescope. Up to date, the Keck telescopes are the only segmented telescope phased with a quality enabling the application of adaptive optics. The Active Phasing Experiment has been installed at the Namyth focus of the Very Large Telescope Melipal during the last 6 months. Its purpose is to understand and compare different technological concepts for an optical phasing sensor dedicated to the European Extremely Large Telescope. The pupil of the telescope is segmented in 61 hexagonal segments by projecting it on an Active Segmented Mirror. The ASM is controlled by a dual wavenlength interferometer made by Fogale Nanotech with a nanometric precision. The segmented pupil is distributed in parallel to four optical phasing sensors. They are a pyramid sensor, a curvature sensor, a phase filtering sensor and a ShackHartmann sensor. They have been developed respectively by Istituto Nazionale di Astrofisica in Florenze, Instituto Astrofisica Canarias in Tenerife, Laboratoire d'Astrophysique de Marseille and ESO. The global behaviour of the optical phasing sensors will be described and preliminary results of the Active Phasing Experiments obtained on sky will be explained. The extrapolation of the results to the EELT and the potential consequences for the adaptive optics will be given. The Active Phasing Experiment has been financed by the European Union and the European Southern Observatory via the Sixth European Union Framework Program for Research and Technological Development under the contract number 011863.

  15. Use of an Extremely Large Telescope for HTRA

    NASA Astrophysics Data System (ADS)

    Ryan, Oliver; Redfern, Mike

    Investigative studies have designed concept instruments for a proposed 42 m European Extremely Large Telescope (E-ELT) facility suite. An ELT will aid, at its most basic level, detection of the faintest stellar sources and instrinsic features, and detailed quantitative analysis of relatively bright sources. The development of such a telescope thus plays to the strengths of high time resolution (HTR) detectors which provide single photon detection capabilities and/or extremely high refresh rates—they can maximize detection of faint sources through photon counting and they can cope with the high photon flux from relatively bright objects building up extremely high S/N. Specific considerations and fast detectors then need to be adopted into the ELT design to accommodate high time resolution astrophysics (HTRA) efficiently. No one instrument or detector can cover all HTRA timescales (nanoseconds to seconds and `slower'), and a dedicated facility HTRA instrument on the ELT is unlikely as yet, but chosen facility instruments can include HTRA options in their packages. Currently there are numerous HTRA options in existing telescope facilities around the world as well as many visiting HTRA instruments. This demonstrates an active HTRA community with worldwide support and interest in HTRA observation capabilities, which underscores the need for HTR capabilities to be designed into the ELT.

  16. The Large Synoptic Survey Telescope concept design overview

    NASA Astrophysics Data System (ADS)

    Krabbendam, Victor L.

    2008-07-01

    The Large Synoptic Survey Telescope Project is a public-private partnership that has successfully completed the Concept Design of its wide-field ground based survey system and started several long-lead construction activities using private funding. The telescope has a 3-mirror wide field optical system with an 8.4 meter primary, 3.4 meter secondary, and 5 meter tertiary mirror. The reflective optics feed three refractive elements and a 64 cm 3.2 gigapixel camera. The telescope will be located on the summit of Cerro Pachón in Chile. The LSST data management system will reduce, transport, alert, archive the roughly 15 terabytes of data produced nightly, and will serve the raw and catalog data accumulating at an average of 7 petabytes per year to the community without any proprietary period. This survey will yield contiguous overlapping imaging of 20,000 square degrees of sky in 6 optical filter bands covering wavelengths from 320 to 1080nm. The project continues to attract institutional partners and has acquired non-federal funding sufficient to construct the primary mirror, already in progress at the University of Arizona, and fund detector prototype efforts, two of the longest lead items in the LSST. The project has submitted a proposal for construction to the National Science Foundation Major Research Equipment and Facilities Construction (MREFC) program and is preparing for a 2011 funding authorization.

  17. Contemporaneous VLBA 5 GHz Observations of Large Area Telescope Detected Blazars

    DTIC Science & Technology

    2012-01-10

    blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma - ray Space Telescope have been observed contemporaneously by the Very Long...galaxies: jets – galaxies: nuclei – gamma rays : galaxies – radio continuum: galaxies 1. INTRODUCTION The Large Area Telescope (LAT; Atwood et al. 2009...on board the Fermi Gamma - ray Space Telescope is a wide-field telescope covering the energy range from about 20 MeV to more than 300 GeV. It has been

  18. The Large Millimeter Telescope and Solar Like Stars

    NASA Astrophysics Data System (ADS)

    Chavez, M.; Hughes, D.; LMT Project Team

    2013-04-01

    This paper describes the current status of the Large Millimeter Telescope (LMT), the near-term plans for the telescope and the initial suite of instrumentation. It also briefly describes two astronomical branches in which the LMT will certainly have a major impact: the study of thermal emission of circumstellar material around main sequence stars and the analysis of the molecular contents of this material in relatively young stars. The LMT is a bi-national collaboration between Mexico and the USA, led by the Instituto Nacional de Astrofísica, Optica y Electrónica (INAOE) and the University of Massachusetts at Amherst, to construct, commission and operate a 50m-diameter millimeter-wave radio telescope. Construction of the telescope structure is complete at the 4600 m LMT site on the summit of Volcán Sierra Negra, an extinct volcano in the Mexican state of Puebla. First-light with the LMT was successfully conducted in June and July 2011 with observations at both 3 and 1.1 mm. The commissioning and future scientific operation of the LMT is divided into two major phases. As part of phase I, following the improvement in the alignment of the surface segments within the inner 32 meter diameter of the antenna, the project will begin the first shared risk scientific observations in the spring of 2013. In phase II, we will continue the installation and alignment of the remainder of the reflector surface, after which the final commissioning of the full 50m LMT will take place. The LMT antenna, outfitted with its initial complement of scientific instruments, will be a world-leading scientific research facility for millimeter-wave astronomy.

  19. Australia to Build Fibre Positioner for the Very Large Telescope

    NASA Astrophysics Data System (ADS)

    1998-06-01

    The Anglo-Australian Observatory (AAO) at Epping (New South Wales, Australia) has been awarded the contract to build a fibre positioner for the European Southern Observatory's Very Large Telescope (VLT). This new, large astronomical facility is located at the Paranal Observatory in Chile and will feature four Unit Telescopes, each with a main mirror of 8.2-m diameter. This positioner, (affectionately) known as the OzPoz , will form part of the FLAMES facility (the F ibre L arge A rea M ulti- E lement S pectrograph), to be mounted on the second Unit Telescope (UT2) of the VLT in 2001. The construction of this facility includes other institutes in Europe, e.g. Observatoire de Genève (Switzerland) and Observatoire de Meudon (France). The ESO Instrument Division will coordinate the entire project that will result in an observational capability that is unique in the world. Optical fibres at astronomical telescopes Optical fibres have come to play an increasingly important role as transmitters of information, for instance in telephone and computer networks. It may be less known that they can be used in a similar way to transmit visible and infrared light in astronomical telescopes. Over the past decade, the AAO has been refining its skills in building optical-fibre instruments for its own telescopes, the 3.9-metre Anglo-Australian Telescope and the 1.2-m UK Schmidt Telescope (a telescope dedicated to wide-field surveys). These instruments enable astronomers to study many celestial objects simultaneously, increasing the effectiveness and productivity by enormous factors. The OzPoz positioner sets up to 560 optical fibres (developed in collaboration with the Observatoire de Meudon in France) very precisely by a robotic arm to match the positions of galaxies and quasars in the telescope's focal plane. The positional accuracy is about 50 µm (0.05 mm), or 0.08 arcsec on the sky. The fibres siphon the light from these very faint and distant astronomical objects and guide it

  20. Recent developments for the Large Binocular Telescope Guiding Control Subsystem

    NASA Astrophysics Data System (ADS)

    Golota, T.; De La Peña, M. D.; Biddick, C.; Lesser, M.; Leibold, T.; Miller, D.; Meeks, R.; Hahn, T.; Storm, J.; Sargent, T.; Summers, D.; Hill, J.; Kraus, J.; Hooper, S.; Fisher, D.

    2014-07-01

    The Large Binocular Telescope (LBT) has eight Acquisition, Guiding, and wavefront Sensing Units (AGw units). They provide guiding and wavefront sensing capability at eight different locations at both direct and bent Gregorian focal stations. Recent additions of focal stations for PEPSI and MODS instruments doubled the number of focal stations in use including respective motion, camera controller server computers, and software infrastructure communicating with Guiding Control Subsystem (GCS). This paper describes the improvements made to the LBT GCS and explains how these changes have led to better maintainability and contributed to increased reliability. This paper also discusses the current GCS status and reviews potential upgrades to further improve its performance.

  1. Lyot coronagraph design study for large, segmented space telescope apertures

    NASA Astrophysics Data System (ADS)

    Zimmerman, Neil T.; N'Diaye, Mamadou; St. Laurent, Kathryn E.; Soummer, Rémi; Pueyo, Laurent; Stark, Christopher C.; Sivaramakrishnan, Anand; Perrin, Marshall; Vanderbei, Robert J.; Kasdin, N. J.; Shaklan, Stuart; Carlotti, Alexis

    2016-07-01

    Recent efforts combining the optimization techniques of apodized pupil Lyot coronagraphs (APLC) and shaped pupils have demonstrated the viability of a binary-transmission mask architecture for extremely high contrast (10-10) exoplanet imaging. We are now building on those innovations to carry out a survey of Lyot coronagraph performance for large, segmented telescope apertures. These apertures are of the same kind under considera- tion for NASA's Large UV/Optical/IR (LUVOIR) observatory concept. To map the multi-dimensional design parameter space, we have developed a software toolkit to manage large sets of mask optimization programs and execute them on a computing cluster. Here we summarize a preliminary survey of 500 APLC solutions for 4 reference hexagonal telescope apertures. Several promising designs produce annular, 10-10 contrast dark zones down to inner working angle 4λ0=D over a 15% bandpass, while delivering a half-max PSF core throughput of 18%. We also report our progress on devising solutions to the challenges of Lyot stop alignment/fabrication tolerance that arise in this contrast regime.

  2. Advanced UVOIR Mirror Technology Development for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2011-01-01

    Objective of this work is to define and initiate a long-term program to mature six inter-linked critical technologies for future UVOIR space telescope mirrors to TRL6 by 2018 so that a viable flight mission can be proposed to the 2020 Decadal Review. (1) Large-Aperture, Low Areal Density, High Stiffness Mirrors: 4 to 8 m monolithic & 8 to 16 m segmented primary mirrors require larger, thicker, stiffer substrates. (2) Support System:Large-aperture mirrors require large support systems to ensure that they survive launch and deploy on orbit in a stress-free and undistorted shape. (3) Mid/High Spatial Frequency Figure Error:A very smooth mirror is critical for producing a high-quality point spread function (PSF) for high-contrast imaging. (4) Segment Edges:Edges impact PSF for high-contrast imaging applications, contributes to stray light noise, and affects the total collecting aperture. (5) Segment-to-Segment Gap Phasing:Segment phasing is critical for producing a high-quality temporally stable PSF. (6) Integrated Model Validation:On-orbit performance is determined by mechanical and thermal stability. Future systems require validated performance models. We are pursuing multiple design paths give the science community the option to enable either a future monolithic or segmented space telescope.

  3. Dark Matter Searches with the Fermi Large Area Telescope

    SciTech Connect

    Meurer, Christine

    2008-12-24

    The Fermi Gamma-Ray Space Telescope, successfully launched on June 11th, 2008, is the next generation satellite experiment for high-energy gamma-ray astronomy. The main instrument, the Fermi Large Area Telescope (LAT), with a wide field of view (>2 sr), a large effective area (>8000 cm{sup 2} at 1 GeV), sub-arcminute source localization, a large energy range (20 MeV-300 GeV) and a good energy resolution (close to 8% at 1 GeV), has excellent potential to either discover or to constrain a Dark Matter signal. The Fermi LAT team pursues complementary searches for signatures of particle Dark Matter in different search regions such as the galactic center, galactic satellites and subhalos, the milky way halo, extragalactic regions as well as the search for spectral lines. In these proceedings we examine the potential of the LAT to detect gamma-rays coming from Weakly Interacting Massive Particle annihilations in these regions with special focus on the galactic center region.

  4. A European vision for a ``Polar Large Telescope'' project

    NASA Astrophysics Data System (ADS)

    Abe, Lyu; Epchtein, Nicolas; Ansorge, Wolfgang; Argentini, Stefania; Bryson, Ian; Carbillet, Marcel; Dalton, Gavin; David, Christine; Esau, Igor; Genthon, Christophe; Langlois, Maud; Le Bertre, Thibault; Lemrani, Rachid; Le Roux, Brice; Marchiori, Gianpietro; Mékarnia, Djamel; Montnacher, Joachim; Moretto, Gil; Prugniel, Philippe; Rivet, Jean-Pierre; Ruch, Eric; Tao, Charling; Tilquin, André; Vauglin, Isabelle

    2013-01-01

    The Polar Large Telescope (PLT) project is primarily aimed at undertaking large, wide band synoptic astronomical surveys in the infrared in order to provide critical data to the forthcoming generation of observational facilities such as ALMA, JWST, LSST and the E-ELT, and to complement the observations obtained with them. Sensitive thermal IR surveys beyond 2.3 μm cannot be carried out from any existing ground based observatory and the Antarctic Plateau is the only place on the ground where it can be envisaged, thanks to its unique atmospheric and environmental properties, such as the turbulence profile (image quality), the low opacity and the reduced thermal background emission of the sky. These unique conditions enable high angular resolution wide field surveys in the near thermal infrared (2.3-5 μm). This spectral range is particularly well suited to tackling key astrophysical questions such as: i) investigating the nature of the distant universe, the first generation of stars and the latest stages of stellar evolution, ii) understanding transient phenomena such as gamma ray-bursts and Type Ia supernovae, iii) increasing our knowledge of extra-solar planets. Further instruments may broaden the expected science outcomes of such a 2-4 m class telescope especially for the characterization of galaxies at very large distance to provide new clues in the mysteries of dark matter and energy. Efforts will be made to merge this project with other comparable projects within an international consortium.

  5. The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission

    SciTech Connect

    Atwood, W.B.; Abdo, Aous A.; Ackermann, M.; Anderson, B. Axelsson, M.; Baldini, L.; Ballet, J.; Band, D.L.; Barbiellini, Guido; Bartelt, J.; Bastieri, Denis; Baughman, B.M.; Bechtol, K.; Bederede, D.; Bellardi, F.; Bellazzini, R.; Berenji, B.; Bignami, G.F.; Bisello, D.; Bissaldi, E.; Blandford, R.D.; /more authors..

    2009-05-15

    The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy {gamma}-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 x 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy {gamma}-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3) measure

  6. Metrology System for a Large, Somewhat Flexible Telescope

    NASA Technical Reports Server (NTRS)

    Liebe, Carl Christian; Bartman, Randall; Cook, Walter; Craig, William

    2009-01-01

    A proposed metrology system would be incorporated into a proposed telescope that would include focusing optics on a rigid bench connected via a deployable mast to another rigid bench holding a focal-plane array of photon counting photodetectors. Deformations of the deployable mast would give rise to optical misalignments that would alter the directions (and, hence, locations) of incidence of photons on the focal plane. The metrology system would measure the relative displacement of the focusing- optics bench and the focal-plane array bench. The measurement data would be used in post-processing of the digitized photodetector outputs to compensate for the mast-deformation-induced changes in the locations of incidence of photons on the focal plane, thereby making it possible to determine the original directions of incidence of photons with greater accuracy. The proposed metrology system is designed specifically for the Nuclear Spectroscopic Telescope Array (NuSTAR) a proposed spaceborne x-ray telescope. The basic principles of design and operation are also applicable to other large, somewhat flexible telescopes, both terrestrial and spaceborne. In the NuSTAR, the structural member connecting the optical bench and the photodetector array would be a 10-m-long deployable mast, and there is a requirement to keep errors in measured directions of incidence of photons below 10 arc seconds (3 sigma). The proposed system would include three diode lasers that would be mounted on the focusing-optics bench. For clarity, only one laser is shown in the figure, which is a greatly simplified schematic diagram of the system. Each laser would be aimed at a position-sensitive photodiode that would be mounted on the detector bench alongside the aforementioned telescope photodetector array. The diode lasers would operate at a wavelength of 830 nm, each at a power of 200 mW. Each laser beam would be focused to a spot of .1-mm diameter on the corresponding position-sensitive photodiode. To

  7. Prospects for Pulsar Studies with the GLAST Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2007-01-01

    The Large Area Telescope (LAT) on the Gamma-ray Large Area Space Telescope (GLAST), due to launch in November 2007, will have unprecedented sensitivity and energy resolution for gamma-rays in the range of 30 MeV to 200 GeV. GLAST is therefore expected to provide major advances in the understanding of high-energy emission from rotation-powered pulsars. As the only presently known galactic GeV source class; pulsars will be one of the most important sources for study with GLAST. The main science goals of the LAT for pulsar studies include an increase in the number of detected radio-loud and radio-quiet gamma-ray pulsars, including millisecond pulsars, giving much better statistics for elucidating population characteristics, measurement of the high-energy spectrum and the shape of spectral cutoffs and determining pulse profiles for a variety of pulsars of different age. Further, measurement of phase-resolved spectra and energy dependent pulse profiles of the brighter pulsars should allow detailed tests of magnetospheric particle acceleration and radiation mechanisms, by comparing data with theoretical models that have been developed. Additionally, the LAT will have the sensitivity to allow blind pulsation searches of nearly all unidentified EGRET sources, to possibly uncover more radio-quiet Geminga-like pulsars.

  8. Prospects for Pulsar Studies with the GLAST Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2006-01-01

    The Large Area Telescope (LAT) on the Gamma-ray Large Area Space Telescope (GLAST) will have unprecedented sensitivity and energy resolution for gamma-rays in the range of 30 MeV to 200 GeV. GLAST is therefore expected to provide major advances in the understanding of high-energy emission from rotation-powered pulsars. As the only presently known galactic GeV source class, pulsars will be one of the most important sources for study with GLAST. The main science goals of the LAT for pulsar studies include an increase in the number of detected radio-loud and radio-quiet gamma ray pulsars, including millisecond pulsars, giving much better statistics for elucidating population characteristics, measurement of the high-energy spectrum and the shape of spectral cutoffs and determining pulse profiles for a variety of pulsars of different age. Further, measurement of phase-resolved spectra and energy dependent pulse profiles of the brighter pulsars should allow detailed tests of magnetospheric particle acceleration and radiation mechanisms, by comparing data with theoretical models that have been developed. Additionally, the LAT will have the sensitivity to allow blind pulsation searches of nearly all unidentified EGRET sources, to possibly uncover more radio-quiet Geminga-like pulsars.

  9. Prospects for Pulsar Studies with the GLAST Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    2007-01-01

    The Large Area Telescope (LAT) on the Gamma-ray Large Area Space Telescope (GLAST), due to launch in November 2007, will have unprecedented sensitivity and energy resolution for gamma-rays in the range of 30 MeV to 200 GeV. GLAST is therefore expected to provide major advances in the understanding of high-energy emission from rotation-powered p ulsars. As the only presently known galactic GeV source class, pulsar s will be one of the most important sources for study with GLAST. The main science goals of the LAT for pulsar studies include an increase in the number of detected radio-loud and radio-quiet gamma-ray pulsar s, including millisecond pulsars, giving much better statistics for e lucidating population characteristics, measurement of the high-energy spectrum and the shape of spectral cutoffs and determining pulse profiles for a variety of pulsars of different age. Further, measurement of phase-resolved spectra and energy dependent pulse profiles of the brighter pulsars should allow detailed tests of magnetospheric partic le acceleration and radiation mechanisms, by comparing data with theo retical models that have been developed. Additionally, the LAT will have the sensitivity to allow blind pulsation searches of nearly all un identified EGRET sources, to possibly uncover more radio-quiet Geming a-like pulsars.

  10. The Gamma-ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    The Gamma-ray Large Area space Telescope, GLAST, is a mission to measure the cosmic gamma-ray flux in the energy range 20 MeV to >300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, GLAST will open a new and important window on a wide variety of phenomena, including black holes and active galactic nuclei; the optical-UV extragalactic background light, gamma-ray bursts; the origin of cosmic rays and supernova remnants; and searches for hypothetical new phenomena such as supersymmetric dark matter annihilations. In addition to the science opportunities, this talk includes a description of the instruments, the opportunities for guest investigators, and the mission status.

  11. Analytical study of diffraction effects in extremely large segmented telescopes.

    PubMed

    Yaitskova, Natalia; Dohlen, Kjetil; Dierickx, Philippe

    2003-08-01

    We present an analysis of the diffraction effects from a segmented aperture with a very large number of segments-prototype of the next generation of extremely large telescopes. This analysis is based on the point-spread-function analytical calculation for Keck-type hexagonal segmentation geometry. We concentrate on the effects that lead to the appearance of speckles and/or a regular pattern of diffraction peaks. These effects are related to random piston and tip-tilt errors on each segment, gaps between segments, and segment edge distortion. We deliver formulas and the typical numerical values for the Strehl ratio, the relative intensity of higher-order diffraction peaks, and the averaged intensity of speckles associated with each particular case of segmentation error.

  12. The Balloon-borne Large Aperture Submillimeter Telescope: BLAST

    NASA Astrophysics Data System (ADS)

    Truch, Matthew D. P.; Ade, P. A. R.; Bock, J. J.; Chapin, E. L.; Chung, J.; Devlin, M. J.; Dicker, S.; Griffin, M.; Gundersen, J. O.; Halpern, M.; Hargrave, P. C.; Hughes, D. H.; Klein, J.; MacTavish, C. J.; Marsden, G.; Martin, P. G.; Martin, T. G.; Mauskopf, P.; Netterfield, C. B.; Olmi, L.; Pascale, E.; Patanchon, G.; Rex, M.; Scott, D.; Semisch, C.; Thomas, N. E.; Tucker, C.; Tucker, G. S.; Viero, M. P.; Wiebe, D. V.

    2009-01-01

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is a suborbital surveying experiment designed to study the evolutionary history and processes of star formation in local galaxies (including the Milky Way) and galaxies at cosmological distances. The BLAST continuum camera, which consists of 270 detectors distributed between three arrays, observes simultaneously in broadband (30%) spectral windows at 250, 350, and 500 microns. The optical design is based on a 2 m diameter telescope, providing a diffraction-limited resolution of 30" at 250 microns. The gondola pointing system enables raster mapping of arbitrary geometry, with a repeatable positional accuracy of 30"; postflight pointing reconstruction to <5" rms is achieved. The onboard telescope control software permits autonomous execution of a preselected set of maps, with the option of manual override. On this poster, we describe the primary characteristics and measured in-flight performance of BLAST. BLAST performed a test flight in 2003 and has since made two scientifically productive long-duration balloon flights: a 100 hour flight from ESRANGE (Kiruna), Sweden to Victoria Island, northern Canada in 2005 June; and a 250 hour, circumpolar flight from McMurdo Station, Antarctica in 2006 December. The BLAST collaboration acknowledges the support of NASA through grants NAG5-12785, NAG5-13301, and NNGO-6GI11G, the Canadian Space Agency (CSA), the Science and Technology Facilities Council (STFC), Canada's Natural Sciences and Engineering Research Council (NSERC), the Canada Foundation for Innovation, the Ontario Innovation Trust, the Puerto Rico Space Grant Consortium, the Fondo Institucional para la Investigacion of the University of Puerto Rico, and the National Science Foundation Office of Polar Programs.

  13. An optical technology study on large aperture telescopes

    NASA Technical Reports Server (NTRS)

    Korsch, D.

    1985-01-01

    The difficult and crucial problem of selecting a suitable telescope concept for an advanced space observatory was examined. To this end two and four mirror telescopes were analyzed and compared. Both configurations are very practical and structurally similar. Parabolic primary and spherical primary four mirror telescope were compared with respect to their performance and the alignment sensitivities of the three correction mirrors. A 1 meter class afocal telescope system with lag angle compensation, to be used in a LIDAR experiment, was examined.

  14. Experimental study of an optimised Pyramid wave-front sensor for Extremely Large Telescopes

    NASA Astrophysics Data System (ADS)

    Bond, Charlotte Z.; El Hadi, Kacem; Sauvage, Jean-François; Correia, Carlos; Fauvarque, Olivier; Rabaud, Didier; Lamb, Masen; Neichel, Benoit; Fusco, Thierry

    2016-07-01

    Over the last few years the Laboratoire d'Astrophysique de Marseille (LAM) has been heavily involved in R&D for adaptive optics systems dedicated to future large telescopes, particularly in preparation for the European Extremely Large Telescope (E-ELT). Within this framework an investigation into a Pyramid wave-front sensor is underway. The Pyramid sensor is at the cutting edge of high order, high precision wave-front sensing for ground based telescopes. Investigations have demonstrated the ability to achieve a greater sensitivity than the standard Shack-Hartmann wave-front sensor whilst the implementation of a Pyramid sensor on the Large Binocular Telescope (LBT) has provided compelling operational results.1, 2 The Pyramid now forms part of the baseline for several next generation Extremely Large Telescopes (ELTs). As such its behaviour under realistic operating conditions must be further understood in order to optimise performance. At LAM a detailed investigation into the performance of the Pyramid aims to fully characterise the behaviour of this wave-front sensor in terms of linearity, sensitivity and operation. We have implemented a Pyramid sensor using a high speed OCAM2 camera (with close to 0 readout noise and a frame rate of 1.5kHz) in order to study the performance of the Pyramid within a full closed loop adaptive optics system. This investigation involves tests on all fronts, from theoretical models and numerical simulations to experimental tests under controlled laboratory conditions, with an aim to fully understand the Pyramid sensor in both modulated and non-modulated configurations. We include results demonstrating the linearity of the Pyramid signals, compare measured interaction matrices with those derived in simulation and evaluate the performance in closed loop operation. The final goal is to provide an on sky comparison between the Pyramid and a Shack-Hartmann wave-front sensor, at Observatoire de la Côte d'Azur (ONERA-ODISSEE bench). Here we

  15. Fermi Large Area Telescope Operations: Progress Over 4 Years

    SciTech Connect

    Cameron, Robert A.; /SLAC

    2012-06-28

    The Fermi Gamma-ray Space Telescope was launched into orbit in June 2008, and is conducting a multi-year gamma-ray all-sky survey, using the main instrument on Fermi, the Large Area Telescope (LAT). Fermi began its science mission in August 2008, and has now been operating for almost 4 years. The SLAC National Accelerator Laboratory hosts the LAT Instrument Science Operations Center (ISOC), which supports the operation of the LAT in conjunction with the Mission Operations Center (MOC) and the Fermi Science Support Center (FSSC), both at NASA's Goddard Space Flight Center. The LAT has a continuous output data rate of about 1.5 Mbits per second, and data from the LAT are stored on Fermi and transmitted to the ground through TDRS and the MOC to the ISOC about 10 times per day. Several hundred computers at SLAC are used to process LAT data to perform event reconstruction, and gamma-ray photon data are subsequently delivered to the FSSC for public release with a few hours of being detected by the LAT. We summarize the current status of the LAT, and the evolution of the data processing and monitoring performed by the ISOC during the first 4 years of the Fermi mission, together with future plans for further changes to detected event data processing and instrument operations and monitoring.

  16. Pupil Alignment Considerations for Large, Deployable Space Telescopes

    NASA Technical Reports Server (NTRS)

    Bos, Brent J.; Ohl, Raymond G.; Kubalak, Daivd A.

    2011-01-01

    For many optical systems the properties and alignment of the internal apertures and pupils are not critical or controlled with high precision during optical system design, fabrication or assembly. In wide angle imaging systems, for instance, the entrance pupil position and orientation is typically unconstrained and varies over the system s field of view in order to optimize image quality. Aperture tolerances usually do not receive the same amount of scrutiny as optical surface aberrations or throughput characteristics because performance degradation is typically graceful with misalignment, generally only causing a slight reduction in system sensitivity due to vignetting. But for a large deployable space-based observatory like the James Webb Space Telescope (JWST), we have found that pupil alignment is a key parameter. For in addition to vignetting, JWST pupil errors cause uncertainty in the wavefront sensing process that is used to construct the observatory on-orbit. Furthermore they also open stray light paths that degrade the science return from some of the telescope s instrument channels. In response to these consequences, we have developed several pupil measurement techniques for the cryogenic vacuum test where JWST science instrument pupil alignment is verified. These approaches use pupil alignment references within the JWST science instruments; pupil imaging lenses in three science instrument channels; and unique pupil characterization features in the optical test equipment. This will allow us to verify and crosscheck the lateral pupil alignment of the JWST science instruments to approximately 1-2% of their pupil diameters.

  17. BLAST: A balloon-borne, large-aperture, submillimetre telescope

    NASA Astrophysics Data System (ADS)

    Wiebe, Donald Victor

    BLAST is a balloon-borne large-aperture, submillimetre telescope, which makes large area (1--200 square degree) surveys of Galactic and extragalactic targets. Since BLAST observes in the stratosphere, it is able to make broad-band observations between 200 mum and 550 mum which are difficult or impossible to perform from the ground. BLAST has been designed to probe star formation both in the local Galaxy and in the high redshift (z = 1--4) universe. Because BLAST is flown on an unmanned stratospheric balloon platform, it has been designed to be able to operate autonomously, without needing operator intervention to perform its scientific goals. This thesis includes an overview of the design of the BLAST platform, with emphasis on the command and control systems used to operate the telescope. BLAST has been flown on two long-duration balloon flights. The first of these, from Esrange, Sweden in June of 2005, acquired ˜70 hours of primarily Galactic data. During the second flight, from Willy Field, Antarctica in December of 2006, BLAST acquired ˜225 hours of both Galactic and extragalactic data. Operational performance of the platform during these two flights is reviewed, with the goal of providing insight on how future flights can be improved. Reduction of the data acquired by these large-format bolometer arrays is a challenging procedure, and techniques developed for BLAST data reduction are reviewed. The ultimate goal of this reduction is the generation of high quality astronomical maps which can be used for subsequent portions of data analysis. This thesis treats, in detail, the iterative, maximum likelihood map maker developed for BLAST. Results of simulations performed on the map maker to characterise its ability to reconstruct astronomical signals are presented. Finally, astronomical maps produced by this map maker using real data acquired by BLAST are presented, with a discussion on non-physical map pathologies resulting from the data reduction pipeline and

  18. Satellite Imaging with Adaptive Optics on a 1 M Telescope

    NASA Astrophysics Data System (ADS)

    Bennet, F.; Price, I.; Rigaut, F.; Copeland, M.

    2016-09-01

    The Research School of Astronomy and Astrophysics at the Mount Stromlo Observatory in Canberra, Australia, have been developing adaptive optic (AO) systems for space situational awareness applications. We report on the development and demonstration of an AO system for satellite imaging using a 1 m telescope. The system uses the orbiting object as a natural guide star to measure atmospheric turbulence, and a deformable mirror to provide an optical correction. The AO system utilised modern, high speed and low noise EMCCD technology on both the wavefront sensor and imaging camera to achieve high performance, achieving a Strehl ratio in excess of 30% at 870 nm. Images are post processed with lucky imaging algorithms to further improve the final image quality. We demonstrate the AO system on stellar targets and Iridium satellites, achieving a near diffraction limited full width at half maximum. A specialised realtime controller allows our system to achieve a bandwidth above 100 Hz, with the wavefront sensor and control loop running at 2 kHz. The AO systems we are developing show how ground-based optical sensors can be used to manage the space environment. AO imaging systems can be used for satellite surveillance, while laser ranging can be used to determine precise orbital data used in the critical conjunction analysis required to maintain a safe space environment. We have focused on making this system compact, expandable, and versatile. We are continuing to develop this platform for other space situational awareness applications such as geosynchronous satellite astrometry, space debris characterisation, satellite imaging, and ground-to-space laser communication.

  19. Preparation research on novel dampers used in large optical telescope's noise and vibrations attenuating system

    NASA Astrophysics Data System (ADS)

    Dong, Xiu-ping; Yang, Jian-chun; Zhang, Li

    2010-10-01

    General rubber damping materials used in noise and vibrations attenuating system can not adapt large optical telescope's working temperatures and environments. While Metal Rubber material which has loose, reticulate structures can endure high or low temperatures, rigorous space environments, erosions, aging, volatilization and radiations due to its metallic properties because it is made of stainless steel wires of φ 0.1~0.3 mm. When the MR damping component is uploaded with vibrating force, the displacement will cause intense frictions between wires' surfaces which will dissipate abundant energy and thus it can serve as dampers like natural rubbers. Since Metal Rubber components are prepared by compression moulding, various complex shapes of dampers can be produced conveniently to fulfill large optical telescope's noise and vibrations attenuating tasks. Based on the Metal Rubber component's four preparation approaches, helix-making, planar roughcast-weaving, planar roughcast-rolling and 3D roughcast punching, a ring-shaped 3D parametrical numerical model is founded by CAD technology. Definitely, this modeling research work may support the optimization of the current trial and try preparation of MR component and it will provide necessary foundations for its further application in noise and vibrations attenuating system in large optical telescopes.

  20. News Note: South African Large Telescope (SALT) reveals too large a black hole

    NASA Astrophysics Data System (ADS)

    2015-10-01

    The Southern African Large Telescope (SALT), has been used to discover a supermassive black hole in the centre of a modest galaxy, SAGE0536AGN. All but the smallest galaxies are thought to harbour black holes, but in this case the black hole was found to be thirty times more massive than what one would have expected for this size galaxy.

  1. Effect of the Keck telescope`s segmented primary on the performance on the Keck adaptive optics system

    SciTech Connect

    Gavel, D.

    1997-06-01

    The 349 degree of freedom Keck adaptive optics system will be mapped on to the 36 segment Keck primary mirror. Each telescope segment is independently controlled in piston and tilt by an active control system and each segment also has its own set of aberrations. This presents a unique set of problems for the Keck adaptive optics system, not encountered with continuous primaries. To a certain extent the low order segment aberrations, beginning with focus, can be corrected statically by the adaptive optic system. However, the discontinuous surface at the segment edges present special problems in sensing and correcting wavefront with laser guide stars or natural guide stars.

  2. Searches for Axionlike Particles with the Fermi Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Albert, Andrea; Meyer, Manuel; Sanchez-Conde, Miguel; Wood, Matthew; LAT Collaboration

    2017-01-01

    Axionlike particles (ALPs) are dark-matter candidates that occur in a variety of extensions of the Standard Model. These particles could leave signatures in gamma rays, due to the coupling of ALPs to photons in external electromagnetic fields. To date, observations with Fermi Large Area Telescope (LAT) provide the strongest constraints on the photon-ALP coupling for ALP masses between 0.5 and 20 neV. Here, we summarize these constraints and present the sensitivity to detect an ALP induced gamma-ray burst from a Galactic core-collapse supernova. ALPs would be produced in the stellar medium via the Primakoff effect and convert into gamma rays in the Galactic magnetic field. Fermi LAT observations would be able to probe couplings where ALPs could constitute the entirety of dark matter. Below 1 neV, the Fermi-LAT sensitivity would surpass that of future laboratory experiments by one order of magnitude.

  3. Telemetry correlation and visualization at the Large Binocular Telescope Observatory

    NASA Astrophysics Data System (ADS)

    Summers, Kellee R.; Summers, Douglas M.; Biddick, Christopher; Hooper, Stephen

    2016-08-01

    To achieve highly efficient observatory operations requires continuous evaluation and improvement of facility and instrumentation metrics. High quality metrics requires a foundation of robust and complete observatory telemetry. At the Large Binocular Telescope Observatory (LBTO), a variety of telemetry-capturing mechanisms exist, but few tools have thus far been created to facilitate studies of the data. In an effort to make all observatory telemetry data easy to use and broadly available, we have developed a suite of tools using in-house development and open source applications. This paper will explore our strategies for consolidating, parameterizing, and correlating any LBTO telemetry data to achieve easily available, web-based two- and three-dimensional time series data visualization.

  4. Camera memory study for large space telescope. [charge coupled devices

    NASA Technical Reports Server (NTRS)

    Hoffman, C. P.; Brewer, J. E.; Brager, E. A.; Farnsworth, D. L.

    1975-01-01

    Specifications were developed for a memory system to be used as the storage media for camera detectors on the large space telescope (LST) satellite. Detectors with limited internal storage time such as intensities charge coupled devices and silicon intensified targets are implied. The general characteristics are reported of different approaches to the memory system with comparisons made within the guidelines set forth for the LST application. Priority ordering of comparisons is on the basis of cost, reliability, power, and physical characteristics. Specific rationales are provided for the rejection of unsuitable memory technologies. A recommended technology was selected and used to establish specifications for a breadboard memory. Procurement scheduling is provided for delivery of system breadboards in 1976, prototypes in 1978, and space qualified units in 1980.

  5. The Second Fermi Large Area Telescope GRB Catalog

    NASA Astrophysics Data System (ADS)

    Kocevski, Daniel; Fermi Large Area Telescope Collaboration

    2017-01-01

    The high-energy emission from gamma-ray bursts (GRBs) is a formidable probe of extreme physics, requiring rapid variability from highly relativistic sources. Despite the advancements in our understanding of GRBs through observations by NASA's Swift and Fermi spacecraft, many fundemental questions regarding the particle acceleration and radiative processes associated with these events remain unanswered. Here we present the most extensive search for emission from GRBs above 40 MeV performed by the Fermi Large Area Telescope (LAT). The resulting catalog includes more than 130 detections and represents an improvement in the detection efficency of GRBs at high-energies of over 50% compared to the first LAT GRB catalog. We utilize this improved sensativity to characterize the high-energy emission from GRBs and review how these observations further our understanding of the nature of these events.

  6. Advanced Mirror Technology Development for Very Large Space Telescopes

    NASA Astrophysics Data System (ADS)

    Stahl, H. P.

    2014-01-01

    Advanced Mirror Technology Development (AMTD) is a NASA Strategic Astrophysics Technology project to mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review. The developed mirror technology must enable missions capable of both general astrophysics & ultra-high contrast observations of exoplanets. Just as JWST’s architecture was driven by launch vehicle, a future UVOIR mission’s architectures (monolithic, segmented or interferometric) will depend on capacities of future launch vehicles (and budget). Since we cannot predict the future, we must prepare for all potential futures. Therefore, to provide the science community with options, we are pursuing multiple technology paths. AMTD uses a science-driven systems engineering approach. We derived engineering specifications for potential future monolithic or segmented space telescopes based on science needs and implement constraints. And we are maturing six inter-linked critical technologies to enable potential future large aperture UVOIR space telescope: 1) Large-Aperture, Low Areal Density, High Stiffness Mirrors, 2) Support Systems, 3) Mid/High Spatial Frequency Figure Error, 4) Segment Edges, 5) Segment-to-Segment Gap Phasing, and 6) Integrated Model Validation Science Advisory Team and a Systems Engineering Team. We are maturing all six technologies simultaneously because all are required to make a primary mirror assembly (PMA); and, it is the PMA’s on-orbit performance which determines science return. PMA stiffness depends on substrate and support stiffness. Ability to cost-effectively eliminate mid/high spatial figure errors and polishing edges depends on substrate stiffness. On-orbit thermal and mechanical performance depends on substrate stiffness, the coefficient of thermal expansion (CTE) and thermal mass. And, segment-to-segment phasing depends on substrate & structure stiffness

  7. The study on servo-control system in the large aperture telescope

    NASA Astrophysics Data System (ADS)

    Hu, Wei; Zhenchao, Zhang; Daxing, Wang

    2008-08-01

    Large astronomical telescope or extremely enormous astronomical telescope servo tracking technique will be one of crucial technology that must be solved in researching and manufacturing. To control technique feature of large astronomical telescope or extremely enormous astronomical telescope, this paper design a sort of large astronomical telescope servo tracking control system. This system composes a principal and subordinate distributed control system, host computer sends steering instruction and receive slave computer functional mode, slave computer accomplish control algorithm and execute real-time control. Large astronomical telescope servo control use direct drive machine, and adopt DSP technology to complete direct torque control algorithm, Such design can not only increase control system performance, but also greatly reduced volume and costs of control system, which has a significant occurrence. The system design scheme can be proved reasonably by calculating and simulating. This system can be applied to large astronomical telescope.

  8. A Digital Motion Control System for Large Telescopes

    NASA Astrophysics Data System (ADS)

    Hunter, T. R.; Wilson, R. W.; Kimberk, R.; Leiker, P. S.

    2001-05-01

    We have designed and programmed a digital motion control system for large telescopes, in particular, the 6-meter antennas of the Submillimeter Array on Mauna Kea. The system consists of a single robust, high-reliability microcontroller board which implements a two-axis velocity servo while monitoring and responding to critical safety parameters. Excellent tracking performance has been achieved with this system (0.3 arcsecond RMS at sidereal rate). The 24x24 centimeter four-layer printed circuit board contains a multitude of hardware devices: 40 digital inputs (for limit switches and fault indicators), 32 digital outputs (to enable/disable motor amplifiers and brakes), a quad 22-bit ADC (to read the motor tachometers), four 16-bit DACs (that provide torque signals to the motor amplifiers), a 32-LED status panel, a serial port to the LynxOS PowerPC antenna computer (RS422/460kbps), a serial port to the Palm Vx handpaddle (RS232/115kbps), and serial links to the low-resolution absolute encoders on the azimuth and elevation axes. Each section of the board employs independent ground planes and power supplies, with optical isolation on all I/O channels. The processor is an Intel 80C196KC 16-bit microcontroller running at 20MHz on an 8-bit bus. This processor executes an interrupt-driven, scheduler-based software system written in C and assembled into an EPROM with user-accessible variables stored in NVSRAM. Under normal operation, velocity update requests arrive at 100Hz from the position-loop servo process running independently on the antenna computer. A variety of telescope safety checks are performed at 279Hz including routine servicing of a 6 millisecond watchdog timer. Additional ADCs onboard the microcontroller monitor the winding temperature and current in the brushless three-phase drive motors. The PID servo gains can be dynamically changed in software. Calibration factors and software filters can be applied to the tachometer readings prior to the application of

  9. The Large Synoptic Survey Telescope preliminary design overview

    NASA Astrophysics Data System (ADS)

    Krabbendam, V. L.; Sweeney, D.

    2010-07-01

    The Large Synoptic Survey Telescope (LSST) Project is a public-private partnership that is well into the design and development of the complete observatory system to conduct a wide fast deep survey and to process and serve the data. The telescope has a 3-mirror wide field optical system with an 8.4 meter primary, 3.4 meter secondary, and 5 meter tertiary mirror. The reflective optics feed three refractive elements and a 64 cm 3.2 gigapixel camera. The LSST data management system will reduce, transport, alert and archive the roughly 15 terabytes of data produced nightly, and will serve the raw and catalog data accumulating at an average of 7 petabytes per year to the community without any proprietary period. The project has completed several data challenges designed to prototype and test the data management system to significant pre-construction levels. The project continues to attract institutional partners and has acquired non-federal funding sufficient to construct the primary mirror, already in progress at the University of Arizona, build the secondary mirror substrate, completed by Corning, and fund detector prototype efforts, several that have been tested on the sky. A focus of the project is systems engineering, risk reduction through prototyping and major efforts in image simulation and operation simulations. The project has submitted a proposal for construction to the National Science Foundation Major Research Equipment and Facilities Construction (MREFC) program and has prepared project advocacy papers for the National Research Council's Astronomy 2010 Decadal Survey. The project is preparing for a 2012 construction funding authorization.

  10. Development of PIAA Complex Mask Coronagraphs for large aperture ground-based telescopes

    NASA Astrophysics Data System (ADS)

    Newman, Kevin; Sirbu, Dan; Belikov, Ruslan; Guyon, Olivier

    2016-07-01

    The Phase Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) is an architecture for directly observing extra-solar planets, and can achieve performance near the theoretical limits for any direct-detection instrument. The PIAACMC architecture includes aspheric PIAA optics, and a complex phase-shifting focal plane mask that provides a pi phase shift to a portion of the on-axis starlight. The phase-shifted starlight is forced to interfere destructively with the un-shifted starlight, causing the starlight to be eliminated, and allowing a region for high-contrast imaging near the star. The PIAACMC architecture can be designed for segmented and obscured apertures, so it is particularly well suited for ground-based observing with the next generation of large telescopes. There will be unique scientific opportunities for directly observing Earth-like planets around nearby low-mass stars. We will discuss design strategies for adapting PIAACMC for the next generation of large ground-based telescopes, and present progress on the development of the focal plane mask technology. We also present simulations of wave-front control with PIAACMC, and suggest directions to apply the coronagraph architecture to future telescopes.

  11. European Extremely Large Telescope: some history, and the scientific community's preferences for wavelength

    NASA Astrophysics Data System (ADS)

    Gilmore, Gerard

    2008-04-01

    Extremely expensive new telescopes involve a compromise between the extreme ambitions of the scientific community, whose support justifies the financial costs, and the need to have a telescope design which can actually be built today at appropriate cost. In this article I provide a brief history of the process which built community support in Europe for what has become the European Extremely Large Telescope project (E-ELT). I then review remaining tensions between the community science case and day-one technical performance. While the range of very strong scientific cases which support the E-ELT project will largely be delivered, and lead to a quite outstanding scientific return, there are - as always! - demands for even more impressive performance. In addition to what the E-ELT will deliver, much of the community wants high spatial resolution at wavelengths shorter than one micron. Affordable adaptive optics systems will work best, initially at somewhat longer wavelengths. Planned performance enhancement during its operational life is very desirable in the E-ELT.

  12. Recent Enhancements of the Phased Array Mirror Extendible Large Aperture (PAMELA) Telescope Testbed at MSFC

    NASA Technical Reports Server (NTRS)

    Rakoczy, John; Montgomery, Edward E.; Lindner, Jeff

    2000-01-01

    Recent incremental upgrades to the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope testbed have enabled the demonstration of phasing (with a monochromatic source) of clusters of primary mirror segments down to the diffraction limit. PAMELA upgrades include an improved Shack-Hartmann wavefront sensor, passive viscoelastic damping treatments for the voice-coil actuators, mechanical improvement of mirror surface figures, and optical bench baffling. This report summarizes the recent PAMELA upgrades, discusses the lessons learned, and presents a status of this unique testbed for wavefront sensing and control. The Marshall Space Flight Center acquired the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope in 1993 after Kaman Aerospace was unable to complete integration and testing under the limited SDIO and DARPA funding. The PAMELA is a 36-segment, half-meter aperture, adaptive telescope which utilizes a Shack-Hartmann wavefront sensor, inductive coil edge sensors, voice coil actuators, imaging CCD cameras and interferometry for figure alignment, wavefront sensing and control. MSFC originally obtained the PAMELA to supplement its research in the interactions of control systems with flexible structures. In August 1994, complete tip, tilt and piston control was successfully demonstrated using the Shack-Hartmann wavefront sensor and the inductive edge sensors.

  13. Recent Enhancements of the Phased Array Mirror Extendible Large Aperture (PAMELA) Telescope Testbed at MSFC

    NASA Technical Reports Server (NTRS)

    Rakoczy, John; Burdine, Robert (Technical Monitor)

    2001-01-01

    Recent incremental upgrades to the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope testbed have enabled the demonstration of phasing (with a monochromatic source) of clusters of primary mirror segments down to the diffraction limit. PAMELA upgrades include in improved Shack-Hartmann wavefront sensor, passive viscoelastic damping treatments for the voice-coil actuators, mechanical improvement of mirror surface figures, and optical bench baffling. This report summarizes the recent PAMELA upgrades, discusses the lessons learned, and presents a status of this unique testbed for wavefront sensing and control. The Marshall Space Flight Center acquired the Phased Array Mirror Extendible Large Aperture (PAMELA) telescope in 1993 after Kaman Aerospace was unable to complete integration and testing under the limited SDIO and DARPA funding. The PAMELA is a 36-segment, half-meter aperture, adaptive telescope which utilizes a Shack-Hartmann wavefront sensor, inductive coil edge sensors, voice coil actuators, imaging CCD cameras and interferometry for figure alignment, wavefront sensing and control. MSFC originally obtained the PAMELA to supplement its research in the interactions of control systems with flexible structures. In August 1994, complete tip, tilt and piston control was successfully demonstrated using the Shack-Hartmann wavefront sensor and the inductive edge sensors.

  14. On-sky single-mode fiber coupling measurements at the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Bechter, Andrew; Crass, Jonathan; Ketterer, Ryan; Crepp, Justin R.; Reynolds, Robert O.; Bechter, Eric; Hinz, Philip; Pedichini, Fernando; Foley, Michael; Runburg, Elliott; Onuma, Eleanya E.; Gaudi, Scott; Micela, Giuseppina; Pagano, Isabella; Woodward, Charles E.

    2016-07-01

    The demonstration of efficient single-mode fiber (SMF) coupling is a key requirement for the development of a compact, ultra-precise radial velocity (RV) spectrograph. iLocater is a next generation instrument for the Large Binocular Telescope (LBT) that uses adaptive optics (AO) to inject starlight into a SMF. In preparation for commissioning iLocater, a prototype SMF injection system was installed and tested at the LBT in the Y-band (0.970-1.065 μm). This system was designed to verify the capability of the LBT AO system as well as characterize on-sky SMF coupling efficiencies. SMF coupling was measured on stars with variable airmasses, apparent magnitudes, and seeing conditions for six half-nights using the Large Binocular Telescope Interferometer. We present the overall optical and mechanical performance of the SMF injection system, including details of the installation and alignment procedure. A particular emphasis is placed on analyzing the instrument's performance as a function of telescope elevation to inform the final design of the fiber injection system for iLocater.

  15. Building ISOC Status Displays for the Large AreaTelescope aboard the Gamma Ray Large Area Space Telescope (GLAST) Observatory

    SciTech Connect

    Ketchum, Christina; /SLAC

    2006-09-01

    In September 2007 the Gamma Ray Large Area Space Telescope (GLAST) is scheduled to launch aboard a Delta II rocket in order to put two high-energy gamma-ray detectors, the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM) into low earth orbit. The Instrument Science Operations Center (ISOC) at SLAC is responsible for the LAT operations for the duration of the mission, and will therefore build an operations center including a monitoring station at SLAC to inform operations staff and visitors of the status of the LAT instrument and GLAST. This monitoring station is to include sky maps showing the location of GLAST in its orbit as well as the LAT's projected field of view on the sky containing known gamma-ray sources. The display also requires a world map showing the locations of GLAST and three Tracking and Data Relay Satellites (TDRS) relative to the ground, their trail lines, and ''footprint'' circles indicating the range of communications for each satellite. The final display will also include a space view showing the orbiting and pointing information of GLAST and the TDRS satellites. In order to build the displays the astronomy programs Xephem, DS9, SatTrack, and STK were employed to model the position of GLAST and pointing information of the LAT instrument, and the programming utilities Python and Cron were used in Unix to obtain updated information from database and load them into the programs at regular intervals. Through these methods the indicated displays were created and combined to produce a monitoring display for the LAT and GLAST.

  16. Fermi Large Area Telescope as a Galactic Supernovae Axionscope.

    PubMed

    Meyer, M; Giannotti, M; Mirizzi, A; Conrad, J; Sánchez-Conde, M A

    2017-01-06

    In a Galactic core-collapse supernova (SN), axionlike particles (ALPs) could be emitted via the Primakoff process and eventually convert into γ rays in the magnetic field of the Milky Way. From a data-driven sensitivity estimate, we find that, for a SN exploding in our Galaxy, the Fermi Large Area Telescope (LAT) would be able to explore the photon-ALP coupling down to g_{aγ}≃2×10^{-13}  GeV^{-1} for an ALP mass m_{a}≲10^{-9}  eV. These values are out of reach of next generation laboratory experiments. In this event, the Fermi LAT would probe large regions of the ALP parameter space invoked to explain the anomalous transparency of the Universe to γ rays, stellar cooling anomalies, and cold dark matter. If no γ-ray emission were to be detected, Fermi-LAT observations would improve current bounds derived from SN 1987A by more than 1 order of magnitude.

  17. The Large Synoptic Survey Telescope project management control system

    NASA Astrophysics Data System (ADS)

    Kantor, Jeffrey P.

    2012-09-01

    The Large Synoptic Survey Telescope (LSST) program is jointly funded by the NSF, the DOE, and private institutions and donors. From an NSF funding standpoint, the LSST is a Major Research Equipment and Facilities (MREFC) project. The NSF funding process requires proposals and D&D reviews to include activity-based budgets and schedules; documented basis of estimates; risk-based contingency analysis; cost escalation and categorization. "Out-of-the box," the commercial tool Primavera P6 contains approximately 90% of the planning and estimating capability needed to satisfy R&D phase requirements, and it is customizable/configurable for remainder with relatively little effort. We describe the customization/configuration and use of Primavera for the LSST Project Management Control System (PMCS), assess our experience to date, and describe future directions. Examples in this paper are drawn from the LSST Data Management System (DMS), which is one of three main subsystems of the LSST and is funded by the NSF. By astronomy standards the LSST DMS is a large data management project, processing and archiving over 70 petabyes of image data, producing over 20 petabytes of catalogs annually, and generating 2 million transient alerts per night. Over the 6-year construction and commissioning phase, the DM project is estimated to require 600,000 hours of engineering effort. In total, the DMS cost is approximately 60% hardware/system software and 40% labor.

  18. The Gamma-Ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    The Gamma-ray Large Area Space Telescope, GLAST, is a mission to measure the cosmic gamma-ray flux in the energy range 20 MeV to more than 300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, GLAST will open a new and important window on a wide variety of high-energy phenomena, including black holes and active galactic nuclei; the optical-UV extragalactic background light, gamma-ray bursts; the origin of cosmic rays and supernova remnants; and searches for signals of hypothetical new phenomena such as supersymmetric dark matter annihilations. In addition to the science opportunities, this talk includes a brief description of the instruments, the opportunities for guest investigators, and the mission status.

  19. The Gamma-ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    The Gamma-ray Large Area Space Telescope, GLAST, is a mission to measure the cosmic gamma-ray flux in the energy range 20 MeV to more than 300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view will make it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its upcoming launch, GLAST will open a new and important window on a wide variety of phenomena, including black holes and active galactic nuclei; the optical-UV extragalactic background light, gamma-ray bursts; the origin of cosmic rays and supernova remnants; and searches for hypothetical new phenomena such as supersymmetric dark matter annihilations and Lorentz invariance violation. In addition to the science opportunities, this talk includes a description of the instruments, the opportunities for guest investigators, and the mission status.

  20. Fermi Large Area Telescope as a Galactic Supernovae Axionscope

    NASA Astrophysics Data System (ADS)

    Meyer, M.; Giannotti, M.; Mirizzi, A.; Conrad, J.; Sánchez-Conde, M. A.

    2017-01-01

    In a Galactic core-collapse supernova (SN), axionlike particles (ALPs) could be emitted via the Primakoff process and eventually convert into γ rays in the magnetic field of the Milky Way. From a data-driven sensitivity estimate, we find that, for a SN exploding in our Galaxy, the Fermi Large Area Telescope (LAT) would be able to explore the photon-ALP coupling down to ga γ≃2 ×10-13 GeV-1 for an ALP mass ma≲10-9 eV . These values are out of reach of next generation laboratory experiments. In this event, the Fermi LAT would probe large regions of the ALP parameter space invoked to explain the anomalous transparency of the Universe to γ rays, stellar cooling anomalies, and cold dark matter. If no γ -ray emission were to be detected, Fermi-LAT observations would improve current bounds derived from SN 1987A by more than 1 order of magnitude.

  1. VERY LARGE TELESCOPE SPECTROPOLARIMETRY OF BROAD ABSORPTION LINE QSOs

    SciTech Connect

    DiPompeo, M. A.; Brotherton, M. S.; De Breuck, C.

    2011-03-15

    We present spectropolarimetry of 19 confirmed and four possible bright, southern broad absorption line (BAL) quasars from the European Southern Observatory Very Large Telescope. A wide range of redshifts is covered in the sample (from 0.9 to 3.4), and both low- and high-ionization quasars are represented, as well as radio-loud and radio-quiet BALQSOs. We continue to confirm previously established spectropolarimetric properties of BALQSOs, including the generally rising continuum polarization with shorter wavelengths and comparatively large fraction with high broadband polarization (6 of 19 with polarizations >2%). Emission lines are polarized less than or similar to the continuum, except in a few unusual cases, and absorption troughs tend to have higher polarizations. A search for correlations between polarization properties has been done, identifying two significant or marginally significant correlations. These are an increase in continuum polarization with decreasing optical luminosity (increasing absolute B magnitude) and decreasing C IV emission-line polarization with increased continuum polarization.

  2. A comparison between using incoherent or coherent sources to align and test an adaptive optical telescope

    NASA Technical Reports Server (NTRS)

    Anderson, Richard

    1994-01-01

    The concept in the initial alignment of the segmented mirror adaptive optics telescope called the phased array mirror extendable large aperture telescope (Pamela) is to produce an optical transfer function (OTF) which closely approximates the diffraction limited value which would correspond to a system pupil function that is unity over the aperture and zero outside. There are differences in the theory of intensity measurements between coherent and incoherent radiation. As a result, some of the classical quantities which describe the performance of an optical system for incoherent radiation can not be defined for a coherent field. The most important quantity describing the quality of an optical system is the OTF and for a coherent source the OTF is not defined. Instead a coherent transfer function (CTF) is defined. The main conclusion of the paper is that an incoherent collimated source and not a collimated laser source is preferred to calibrate the Hartmann wavefront sensor (WFS) of an aligned adaptive optical system. A distant laser source can be used with minimum problems to correct the system for atmospheric turbulence. The collimation of the HeNe laser alignment source can be improved by using a very small pin hole in the spatial filter so only the central portion of the beam is transmitted and the beam from the filter is nearly constant in amplitude. The size of this pin hole will be limited by the sensitivity of the lateral effect diode (LEDD) elements.

  3. Simulation and analysis of laser guide star adaptive optics systems for the eight to ten meter class telescopes

    SciTech Connect

    Gavel, D.T.; Olivier, S.S.

    1994-03-01

    This paper discusses the design and analysis of laser-guided adaptive optic systems for the large, 8--10 meter class telescopes. We describe a technique for calculating the expected modulation transfer function and the point spread function for a closed loop adaptive optics system, parameterized by the degree of correction and the seeing conditions. The results agree closely with simulations and experimental data, and validate well known scaling law models even at low order correction. Scaling law.model analysis of a proposed adaptive optics system at the Keck telescope leads to the conclusion that a single laser guide star beacon will be adequate for diffraction limited imaging at wavelengths between 1 and 3 am with reasonable coverage of the sky. Cone anisoplanatism will dominate wavefront correction error at the visible wavelengths unless multiple laser guide stars are used.

  4. Solar System science with the Large Synoptic Survey Telescope

    NASA Astrophysics Data System (ADS)

    Jones, Lynne; Brown, Mike; Ivezić, Zeljko; Jurić, Mario; Malhotra, Renu; Trilling, David

    2015-11-01

    The Large Synoptic Survey Telescope (LSST; http://lsst.org) will be a large-aperture, wide-field, ground-based telescope that will survey half the sky every few nights in six optical bands from 320 to 1050 nm. It will explore a wide range of astrophysical questions, ranging from performing a census of the Solar System, to examining the nature of dark energy. It is currently in construction, slated for first light in 2019 and full operations by 2022.The LSST will survey over 20,000 square degrees with a rapid observational cadence, to typical limiting magnitudes of r~24.5 in each visit (9.6 square degree field of view). Automated software will link the individual detections into orbits; these orbits, as well as precisely calibrated astrometry (~50mas) and photometry (~0.01-0.02 mag) in multiple bandpasses will be available as LSST data products. The resulting data set will have tremendous potential for planetary astronomy; multi-color catalogs of hundreds of thousands of NEOs and Jupiter Trojans, millions of asteroids, tens of thousands of TNOs, as well as thousands of other objects such as comets and irregular satellites of the major planets.LSST catalogs will increase the sample size of objects with well-known orbits 10-100 times for small body populations throughout the Solar System, enabling a major increase in the completeness level of the inventory of most dynamical classes of small bodies and generating new insights into planetary formation and evolution. Precision multi-color photometry will allow determination of lightcurves and colors, as well as spin state and shape modeling through sparse lightcurve inversion. LSST is currently investigating survey strategies to optimize science return across a broad range of goals. To aid in this investigation, we are making a series of realistic simulated survey pointing histories available together with a Python software package to model and evaluate survey detections for a user-defined input population. Preliminary

  5. The Dobsonian telescope. A practical manual for building large aperture telescopes.

    NASA Astrophysics Data System (ADS)

    Kriege, D.; Berry, R.

    This book tells how you can build a state-of-the-art Dobsonian telescope using readily available materials and supplies. Every step of construction is detailed in photographs and diagrams, and the underlying ideas are carefully explained. As a result of a three-year collaboration between the authors, experienced and well-known telescope makers, one now has the opportunity to build a high-performance telescope with a 14-inch to 40-inch aperture based on the thoroughly tested designs described in this book.

  6. FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE VELA PULSAR

    SciTech Connect

    Abdo, A. A.; Ackermann, M.; Bartelt, J.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bogart, J. R.; Atwood, W. B.; Bagagli, R.; Baldini, L.; Bellardi, F.; Bellazzini, R.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bisello, D.; Baughman, B. M. E-mail: massimiliano.razzano@pi.infn.it

    2009-05-10

    The Vela pulsar is the brightest persistent source in the GeV sky and thus is the traditional first target for new {gamma}-ray observatories. We report here on initial Fermi Large Area Telescope observations during verification phase pointed exposure and early sky survey scanning. We have used the Vela signal to verify Fermi timing and angular resolution. The high-quality pulse profile, with some 32,400 pulsed photons at E {>=} 0.03 GeV, shows new features, including pulse structure as fine as 0.3 ms and a distinct third peak, which shifts in phase with energy. We examine the high-energy behavior of the pulsed emission; initial spectra suggest a phase-averaged power-law index of {gamma} = 1.51{sup +0.05} {sub -0.04} with an exponential cutoff at E{sub c} = 2.9 {+-} 0.1 GeV. Spectral fits with generalized cutoffs of the form e{sup -(E/E{sub c}){sup b}} require b {<=} 1, which is inconsistent with magnetic pair attenuation, and thus favor outer-magnetosphere emission models. Finally, we report on upper limits to any unpulsed component, as might be associated with a surrounding pulsar wind nebula.

  7. Replacing a technology - The Large Space Telescope and CCDs

    NASA Technical Reports Server (NTRS)

    Smith, R. W.; Tatarewicz, J. H.

    1985-01-01

    The technological improvements, design choices and mission goals which led to the inclusion of CCD detectors in the wide field camera of the Large Space Telescope (LST) to be launched by the STS are recounted. Consideration of CCD detectors began before CCDs had seen wide astronomical applications. During planning for the ST, in the 1960s, photographic methods and a vidicon were considered, and seemed feasible provided that periodic manual maintenance could be performed. The invention of CCDs was first reported in 1970 and by 1973 the CCDs were receiving significant attention as potential detectors instead of a vidicon, which retained its own technological challenges. The CCD format gained new emphasis when success was achieved in developments for planetary-imaging spacecraft. The rapidity of progress in CCD capabilities, coupled with the continued shortcomings of the vidicon, resulted in a finalized choice for a CCD device by 1977. The decision was also prompted by continuing commercial and military interest in CCDs, which was spurring the development of the technology and improving the sensitivities and reliability while lowering the costs.

  8. FERMI LARGE AREA TELESCOPE DETECTION OF SUPERNOVA REMNANT RCW 86

    SciTech Connect

    Yuan, Qiang; Huang, Xiaoyuan; Liu, Siming; Zhang, Bing

    2014-04-20

    Using 5.4 yr Fermi Large Area Telescope data, we report the detection of GeV γ-ray emission from the shell-type supernova remnant RCW 86 (G315.4-2.3) with a significance of ∼5.1σ. The data slightly favors an extended emission of this supernova remnant. The spectral index of RCW 86 is found to be very hard, Γ ∼ 1.4, in the 0.4-300 GeV range. A one-zone leptonic model can well fit the multi-wavelength data from radio to very high energy γ-rays. The very hard GeV γ-ray spectrum and the inferred low gas density seem to disfavor a hadronic origin for the γ-rays. The γ-ray behavior of RCW 86 is very similar to several other TeV shell-type supernova remnants, e.g., RX J1713.7-3946, RX J0852.0-4622, SN 1006, and HESS J1731-347.

  9. EXO-ZODI MODELING FOR THE LARGE BINOCULAR TELESCOPE INTERFEROMETER

    SciTech Connect

    Kennedy, Grant M.; Wyatt, Mark C.; Panić, Olja; Shannon, Andrew; Bailey, Vanessa; Defrère, Denis; Hinz, Philip M.; Rieke, George H.; Skemer, Andrew J.; Su, Katherine Y. L.; Bryden, Geoffrey; Mennesson, Bertrand; Morales, Farisa; Serabyn, Eugene; Danchi, William C.; Roberge, Aki; Stapelfeldt, Karl R.; Haniff, Chris; Lebreton, Jérémy; Millan-Gabet, Rafael; and others

    2015-02-01

    Habitable zone dust levels are a key unknown that must be understood to ensure the success of future space missions to image Earth analogs around nearby stars. Current detection limits are several orders of magnitude above the level of the solar system's zodiacal cloud, so characterization of the brightness distribution of exo-zodi down to much fainter levels is needed. To this end, the Large Binocular Telescope Interferometer (LBTI) will detect thermal emission from habitable zone exo-zodi a few times brighter than solar system levels. Here we present a modeling framework for interpreting LBTI observations, which yields dust levels from detections and upper limits that are then converted into predictions and upper limits for the scattered light surface brightness. We apply this model to the HOSTS survey sample of nearby stars; assuming a null depth uncertainty of 10{sup –4} the LBTI will be sensitive to dust a few times above the solar system level around Sun-like stars, and to even lower dust levels for more massive stars.

  10. Spherical Primary Optical Telescope (SPOT): An Architecture Demonstration for Cost-effective Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee D.; Hagopian, John; Budinoff, Jason; Dean, Bruce; Howard, Joe

    2004-01-01

    This paper summarizes efforts underway at the Goddard Space Flight Center to demonstrate a new type of space telescope architecture that builds on the rigid segmented telescope heritage of the James Webb Space Telescope but that solves several key challenges for future space telescopes. The architecture is based on a cost-effective segmented spherical primary mirror combined with a unique wavefront sensing and control system that allows for continuous phasing of the primary mirror. The segmented spherical primary allows for cost-effective 3-meter class (e.g., Midex and Discovery) missions as well as enables 30-meter telescope solutions that can be manufactured in a reasonable amount of time and for a reasonable amount of money. The continuous wavefront sensing and control architecture enables missions in low-earth-orbit and missions that do not require expensive stable structures and thermal control systems. For the 30-meter class applications, the paper discusses considerations for assembling and testing the telescopes in space. The paper also summarizes the scientific and technological roadmap for the architecture and also gives an overview of technology development, design studies, and testbed activities underway to demonstrate its feasibility.

  11. Spherical Primary Optical Telescope (SPOT): An Architecture Demonstration for Cost-effective Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee; Hagopian, John; Budinoff, Jason; Dean, Bruce; Howard, Joe

    2005-01-01

    This paper summarizes efforts underway at the Goddard Space Flight Center to demonstrate a new type of space telescope architecture that builds on the rigid, segmented telescope heritage of the James Webb Space Telescope but that solves several key challenges for future space telescopes. The architecture is based on a cost-effective segmented spherical primary mirror combined with a unique wavefront sensing and control system that allows for continuous phasing of the primary mirror. The segmented spherical primary allows for cost-effective 3-meter class (eg, Midex and Discovery) missions as well as enables 30-meter telescope solutions that can be manufactured in a reasonable amount of time and for a reasonable amount of money. The continuous wavefront sensing and control architecture enables missions in low-earth-orbit and missions that do not require expensive stable structures and thermal control systems. For the 30-meter class applications, the paper discusses considerations for assembling and testing the telescopes in space. The paper also summarizes the scientific and technological roadmap for the architecture and also gives an overview of technology development, design studies, and testbed activities underway to demonstrate it s feasibility.

  12. CAMERA: a compact, automated, laser adaptive optics system for small aperture telescopes

    NASA Astrophysics Data System (ADS)

    Britton, Matthew; Velur, Viswa; Law, Nick; Choi, Philip; Penprase, Bryan E.

    2008-07-01

    CAMERA is an autonomous laser guide star adaptive optics system designed for small aperture telescopes. This system is intended to be mounted permanently on such a telescope to provide large amounts of flexibly scheduled observing time, delivering high angular resolution imagery in the visible and near infrared. The design employs a Shack Hartmann wavefront sensor, a 12x12 actuator MEMS device for high order wavefront compensation, and a solid state 355nm ND:YAG laser to generate a guide star. Commercial CCD and InGaAs detectors provide coverage in the visible and near infrared. CAMERA operates by selecting targets from a queue populated by users and executing these observations autonomously. This robotic system is targeted towards applications that are diffcult to address using classical observing strategies: surveys of very large target lists, recurrently scheduled observations, and rapid response followup of transient objects. This system has been designed and costed, and a lab testbed has been developed to evaluate key components and validate autonomous operations.

  13. Adaptive Control Of Large Vibrating, Rotating Structures

    NASA Technical Reports Server (NTRS)

    Bayard, David S.

    1991-01-01

    Globally convergent theoretical method provides for adaptive set-point control of orientation of, along with suppression of the vibrations of, large structure. Method utilizes inherent passivity properties of structure to attain mathematical condition essential to adaptive convergence on commanded set point. Maintains stability and convergence in presence of errors in mathematical model of dynamics of structure and actuators. Developed for controlling attitudes of large, somewhat flexible spacecraft, also useful in such terrestrial applications as controlling movable bridges or suppressing earthquake vibrations in bridges, buildings, and other large structures.

  14. Asteroid Detection with the Large Synoptic Survey Telescope (LSST)

    NASA Astrophysics Data System (ADS)

    Jones, Lynne

    2015-08-01

    The Large Synoptic Survey Telescope (LSST) will be a ground-based, optical, all-sky, rapid cadence survey project with tremendous potential for discovering and characterizing asteroids. With LSST's large 6.5m diameter, wide 9.6 square degree field of view, and rapid observational cadence, LSST will discover more than 5 million asteroids over its ten year survey lifetime. Building on the results of existing surveys such as NEO-WISE, SDSS and PanSTARRS, this will provide a wealth of information about the dynamical structure and physical properties of the main asteroid belt.With a single visit limiting magnitude of 24.5 in r band, LSST will detect asteroids in the main belt down to sub-kilometer sizes. This results in a substantial overlap between the detected main belt asteroids and known NEO population, providing better understanding of the source population for NEOs. The current strawman for the LSST observational cadence is two visits (each visit is a pair of back-to-back 15 second exposures) per field separated by about 30 minutes, covering the entire visible sky every 3-4 days throughout the observing season. Most main belt asteroids will receive on the order of 200-300 observations, with visits spread between six broadband filters, ugrizy. When coupled with LSST's precise photometric and astrometric calibration, a significant fraction of the asteroid sample will obtain colors accurate to about 0.02-0.05 magnitudes and with sufficient number of observations to perform sparse lightcurve inversion. This dataset will increase the number of asteroids with photometric colors, and the number of objects with rotation period and shape information, by more than an order of magnitude, and provide unprecedented measurements of Yarkovsky effects and YORP evolution. Color information combined with proper orbital elements will enable identification of asteroid families down to much smaller sizes, permitting size distribution measurements and providing constraints on the

  15. Asteroid Discovery and Characterization with the Large Synoptic Survey Telescope

    NASA Astrophysics Data System (ADS)

    Jones, R. Lynne; Jurić, Mario; Ivezić, Željko

    2016-01-01

    The Large Synoptic Survey Telescope (LSST) will be a ground-based, optical, all-sky, rapid cadence survey project with tremendous potential for discovering and characterizing asteroids. With LSST's large 6.5m diameter primary mirror, a wide 9.6 square degree field of view 3.2 Gigapixel camera, and rapid observational cadence, LSST will discover more than 5 million asteroids over its ten year survey lifetime. With a single visit limiting magnitude of 24.5 in r band, LSST will be able to detect asteroids in the Main Belt down to sub-kilometer sizes. The current strawman for the LSST survey strategy is to obtain two visits (each `visit' being a pair of back-to-back 15s exposures) per field, separated by about 30 minutes, covering the entire visible sky every 3-4 days throughout the observing season, for ten years. The catalogs generated by LSST will increase the known number of small bodies in the Solar System by a factor of 10-100 times, among all populations. The median number of observations for Main Belt asteroids will be on the order of 200-300, with Near Earth Objects receiving a median of 90 observations. These observations will be spread among ugrizy bandpasses, providing photometric colors and allow sparse lightcurve inversion to determine rotation periods, spin axes, and shape information. These catalogs will be created using automated detection software, the LSST Moving Object Processing System (MOPS), that will take advantage of the carefully characterized LSST optical system, cosmetically clean camera, and recent improvements in difference imaging. Tests with the prototype MOPS software indicate that linking detections (and thus `discovery') will be possible at LSST depths with our working model for the survey strategy, but evaluation of MOPS and improvements in the survey strategy will continue. All data products and software created by LSST will be publicly available.

  16. Paper Productivity of Ground-based Large Optical Telescopes from 2000 to 2009

    NASA Astrophysics Data System (ADS)

    Kim, Sang Chul

    2011-08-01

    We present an analysis of the scientific (refereed) paper productivity of the current largest (diameter>8m) ground-based optical (and infrared) telescopes during the ten-year period from 2000 to 2009. The telescopes for which we have gathered and analysed the scientific publication data are the two 10-m Keck telescopes, the four 8.2-m Very Large Telescopes (VLT), the two 8.1-m Gemini telescopes, the 8.2-m Subaru telescope, and the 9.2-m Hobby-Eberly Telescope (HET). We have analysed the numbers of papers published in various astronomical journals produced by using these telescopes. While the total numbers of papers from these observatories are largest for the VLT, followed by Keck, Gemini, Subaru, and HET, the number of papers produced by each component of the telescopes is largest for Keck, followed by VLT, Subaru, Gemini, and HET. In 2009, each telescope of the Keck, VLT, Gemini, Subaru, and HET observatories produced 135, 109, 93, 107, and 5 refereed papers, respectively. We have shown that each telescope of the Keck, VLT, Gemini, and Subaru observatories is producing 2.1+/-0.9 Nature and Science papers annually and these papers make up 1.7+/-0.8% of all refereed papers produced by using each of those telescopes. Extending this relation, we propose that this ratio of the number of Nature and Science papers to the total number of refereed papers that will be produced by future extremely large telescopes (ELTs) will remain similar. From a comparison of the publication trends of the above telescopes, we suggest that (i) having more than one telescope of the same kind at the same location and (ii) increasing the number of instruments available at the telescope are good ways to maximize the paper productivity.

  17. Fundamental gain in high-contrast imaging with the large binocular telescope interferometer

    NASA Astrophysics Data System (ADS)

    Patru, Fabien; Esposito, Simone; Puglisi, Alfio; Riccardi, Armando; Pinna, Enrico; Arcidiacono, Carmelo; Hill, John; Hinz, Philip

    2016-08-01

    Numerical simulations for the Large Binocular Telescope Interferometer have shown a fundamental gain in contrast when using two 8m adaptive optics telescopes instead of one, assuming a high Strehl and a cophasing mode. The global gain is improved by a factor 2 in contrast by using the long exposures and by a factor of 10 in contrast by using the short exposures. Indeed, fringes are still present in the short exposure, contrary to the long exposure where the fringes are blurred. Thus, there is some gain in grouping some short exposures with high gain G. This makes the LBTI well suitable for the Angular Differential Imaging technique. A planet will be alternatively located in the dark fringes (G ≈ 10 to 100) and/or in the dark rings (G ≈ 4 to 20). A rotation of 15° is sufficient to pass through at least one gain zone. The LBTI can provide in the visible wavelengths not only high angular resolution (≈ 6:5mas at 750nm) and high sensitivity (by a factor 4), but also a gain in contrast (by a factor 10 to 100) compared to the stand-alone adaptive optics used on each LBT aperture.

  18. Large size SiPM matrix for Imaging Atmospheric Cherenkov Telescopes applications

    NASA Astrophysics Data System (ADS)

    Ambrosi, G.; Corti, D.; Ionica, M.; Manea, C.; Mariotti, M.; Rando, R.; Reichardt, I.; Schultz, C.

    2016-07-01

    SiPM photo detectors are nowadays commonly used in many applications. For large size telescopes like MAGIC or the future Large Size Telescope (LST) of the Cherenkov Telescope Array (CTA) project, a pixel size of some square centimeters is needed. An analog amplifier and sum stage was built and characterized. A large and compact SiPM matrix prototype, with the associated focusing optics, was assembled into a monolithic light detector with an active area of 3 cm2. The performance of the electronics is tailored for Imaging Atmospheric Cherenkov Telescopes (IACT) applications, with fast signal and adequate signal-to-noise (S/N) ratio.

  19. A flat array large telescope concept for use on the moon, earth, and in space

    NASA Technical Reports Server (NTRS)

    Woodgate, Bruce E.

    1991-01-01

    An astronomical optical telescope concept is described which can provide very large collecting areas, of order 1000 sq m. This is an order of magnitude larger than the new generation of telescopes now being designed and built. Multiple gimballed flat mirrors direct the beams from a celestial source into a single telescope of the same aperture as each flat mirror. Multiple images of the same source are formed at the telescope focal plane. A beam combiner collects these images and superimposes them into a single image, onto a detector or spectrograph aperture. This telescope could be used on the earth, the moon, or in space.

  20. GLAST large area telescope - daily survey of high energy sky

    NASA Astrophysics Data System (ADS)

    Kamae, Tuneyoshi

    2003-07-01

    GLAST Large Area Telescope was proposed to NASA in 1999 as a follow-up of EGRET on-board Compton Gamma-Ray Observatory by an international collaboration. The proposal has been approved as a part of the GLAST observatory mission in its capability to explore a wide range of astrophysics with 5-40 times higher sensitivity and extended energy coverage (20MeV to 300GeV) than EGRET. The instrument consists of 16 towers of e+e- pair tracker, 16 blocks of segmented electro-magnetic calorimeter, and a set of anti-coicidence plastic scintillator tiles covering the tracker towers. It will have 5-10 times larger on-axis effective area, 6 times wider field-of-view (FOV), and up to 5 times better angular resolution when compared with EGRET. The Large Area Telescope will cover about 40% of the sky above the Earth's horizon in its FOV at any given time and will scan nearly the entire Universe every orbit (~ 90min): about 20% of Gamma-Ray Bursts will be observed from the onset of the bursts to the initial after-glow phase; all longer-lasting transients and variabilities will be detected daily at the improved sensitivity. The instrument has been prototyped twice between 1995 and 2001, designed almost to the Flight Model by the international collaboration of the US (NASA and DoE), France, Italy, Japan, and Sweden. The first prototype consisted of one tower of e+e- pair trackers, one block of segmented calorimeters and a smaller set of anti-coicidence plastic scintillator tiles (Beam Test Engineering Model, BTEM), which was put into e+, p, and γ beams at SLAC in the winter of 1999-2000. It was subsequently modified for a balloon experiment (Balloon Flight Engineering Model, BFEM) and flown at Palestine, Texas in August 2001. Data collected in the test experiments have been analyzed and compared with predictions of computer simulation codes such as Geant4. These studies have confirmed validity of the basic design, brought up a few issues for further improvement, and gathered data on

  1. Automated Science Processing for the Fermi Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Chiang, James

    2012-03-01

    The Large Area Telescope (LAT) onboard the Fermi γ-ray Space Telescope provides high sensitivity to emission from astronomical sources over a broad energy range (20MeV to >300 GeV) and has substantially improved spatial, energy, and timing resolution compared with previous observatories at these energies [4]. One of the LAT's most innovative features is that it performs continuous monitoring of the gamma-ray sky with all-sky coverage every 3 h. This survey strategy greatly enables the search for transient behavior from both previously known and unknown sources. In addition, the constant accumulation of data allows for increasingly improved measurements of persistent sources. These include the Milky Way Galaxy itself, which produces gamma-ray emission as a result from interactions of cosmic rays with gas in the Galaxy, and potential signals from candidate dark matter particles in the Milky Way and its neighboring galaxies. The automated science processing (ASP) functionality of the Fermi Instrument Science Operations Center (ISOC) is a part of the automated data pipeline that processes the raw data arriving from the spacecraft and puts it into a form amenable to scientific analysis. ASP operates at the end of the pipeline on the processed data and is intended to detect and characterize transient behavior (e.g., short time scale increases or “flares” in the gamma-ray flux) from astronomical sources. On detection of a flaring event, ASP will alert other observatories on a timely basis so that they may train their telescopes on the flaring source in order to detect possible correlated activity in other wavelength bands. Since the data from the LAT is archived and publicly available as soon as it is processed, ASP serves mainly to provide triggers for those follow-up observations; its estimates of the properties of the flaring sources (flux, spectral index, location) need not be the best possible, as subsequent off-line analysis can provide more refined

  2. Large-Aperture, Three Mirror Telescopes for Near-Earth

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; McGraw, J.

    In this era when Space Situational Awareness (SSA) is a national priority and optical-infrared telescopic sensor development is underway, cost-benefit analyses of competing approaches are necessary and appropriate. The DOD is presently investing in a new three-mirror telescope for SSA. At the same time, the Air Force, various universities and private research organizations are either studying or building wide-field telescopes with similar capabilities, but in most cases, at a significantly lower cost. Much of the expense for the DOD system appears driven by certain design choices which were advertised as necessary to fulfill the mission. Design details which would allow an independent analysis have not been published and no public comparison with other approaches is known to exist. Most telescope designs however, can be closely approximated from their optical configuration and imaging performance specifications. An optical designer will tell you that field curvature is one of the five monochromatic aberrations which they try to eliminate. The fact that one DOD development effort considers field curvature a design feature immediately draws attention to the project. This coupled with the paucity of published information and the very high development cost makes this program irresistible for comparison with competing approaches. This paper examines the likely design and performance of a proxy telescope intended to find NEOs, compares and contrasts that telescope with similar, but lower cost on-going projects, and examines the predictable impacts of reproducing such a telescope and placing multiple copies around the globe. The study primarily concentrates on performance measured in terms of search rate in square degrees per hour vs. object visual magnitude. Other considerations such as cost, transportability, availability of replacement components and ease of installation are also considered.

  3. Performance of the Fourier transform reconstructor for the European Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Montilla, I.; Reyes, M.; Le Louarn, M.; Marichal-Hernández, J. G.; Rodríguez-Ramos, J. M.; Rodríguez-Ramos, L. F.

    2008-07-01

    The forthcoming Extremely Large Telescopes, and the new generation of Extreme Adaptive Optics systems, carry on a boost in the number of actuators that makes the real-time correction of the atmospheric aberration computationally challenging. It is necessary to study new algorithms for performing Adaptive Optics at the required speed. Among the last generation algorithms that are being studied, the Fourier Transform Reconstructor (FTR) appears as a promising candidate. Its feasibility to be used for Single-Conjugate Adaptive Optics has been extensively proved by Poyneer et al.[1] As part of the activities supported by the ELT Design Study (European Community's Framework Programme 6) we have studied the performance of this algorithm applied to the case of the European ELT, in two different cases: single-conjugate and ground-layer adaptive optics and we are studying different approaches to apply it to the more complex multi-conjugate case. The algorithm has been tested on ESO's OCTOPUS software, which simulates the atmosphere, the deformable mirror, the sensor and the closed-loop control. The performance has been compared with other algorithms as well as their response in the presence of noise and with various atmospheric conditions. The good results on performance and robustness, and the possibility of parallelizing the algorithm (shown by Rodríguez-Ramos and Marichal-Hernández) make it an excellent alternative to the typically used Matrix-Vector Multiply algorithm.

  4. Large Synoptic Survey Telescope: From Science Drivers to Reference Design

    SciTech Connect

    Ivezic, Z.; Axelrod, T.; Brandt, W.N.; Burke, D.L.; Claver, C.F.; Connolly, A.; Cook, K.H.; Gee, P.; Gilmore, D.K.; Jacoby, S.H.; Jones, R.L.; Kahn, S.M.; Kantor, J.P.; Krabbendam, V.; Lupton, R.H.; Monet, D.G.; Pinto, P.A.; Saha, A.; Schalk, T.L.; Schneider, D.P.; Strauss, Michael A.; /Washington U., Seattle, Astron. Dept. /LSST Corp. /Penn State U., Astron. Astrophys. /KIPAC, Menlo Park /NOAO, Tucson /LLNL, Livermore /UC, Davis /Princeton U., Astrophys. Sci. Dept. /Naval Observ., Flagstaff /Arizona U., Astron. Dept. - Steward Observ. /UC, Santa Cruz /Harvard U. /Johns Hopkins U. /Illinois U., Urbana

    2011-10-14

    In the history of astronomy, major advances in our understanding of the Universe have come from dramatic improvements in our ability to accurately measure astronomical quantities. Aided by rapid progress in information technology, current sky surveys are changing the way we view and study the Universe. Next-generation surveys will maintain this revolutionary progress. We focus here on the most ambitious survey currently planned in the visible band, the Large Synoptic Survey Telescope (LSST). LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: constraining dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. It will be a large, wide-field ground-based system designed to obtain multiple images covering the sky that is visible from Cerro Pachon in Northern Chile. The current baseline design, with an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg{sup 2} field of view, and a 3,200 Megapixel camera, will allow about 10,000 square degrees of sky to be covered using pairs of 15-second exposures in two photometric bands every three nights on average. The system is designed to yield high image quality, as well as superb astrometric and photometric accuracy. The survey area will include 30,000 deg{sup 2} with {delta} < +34.5{sup o}, and will be imaged multiple times in six bands, ugrizy, covering the wavelength range 320-1050 nm. About 90% of the observing time will be devoted to a deep-wide-fast survey mode which will observe a 20,000 deg{sup 2} region about 1000 times in the six bands during the anticipated 10 years of operation. These data will result in databases including 10 billion galaxies and a similar number of stars, and will serve the majority of science programs. The remaining 10% of the observing time will be allocated to special programs such as Very Deep and Very Fast time domain surveys. We describe how the

  5. Adaptable radiative transfer innovations for submillimetre telescopes (ARTIST). Dust polarisation module (DustPol)

    NASA Astrophysics Data System (ADS)

    Padovani, M.; Brinch, C.; Girart, J. M.; Jørgensen, J. K.; Frau, P.; Hennebelle, P.; Kuiper, R.; Vlemmings, W. H. T.; Bertoldi, F.; Hogerheijde, M.; Juhasz, A.; Schaaf, R.

    2012-07-01

    We present a new publicly available tool (DustPol) aimed to model the polarised thermal dust emission. The module DustPol, which is publicly available, is part of the ARTIST (Adaptable Radiative Transfer Innovations for Submillimetre Telescopes) package, which also offers tools for modelling the polarisation of line emission together with a model library and a Python-based user interface. DustPol can easily manage analytical as well as pre-gridded models to generate synthetic maps of the Stokes I, Q, and U parameters. These maps are stored in FITS format which is straightforwardly read by the data reduction software used, e.g., by the Atacama Large Millimeter Array (ALMA). This turns DustPol into a powerful engine for the prediction of the expected polarisation features of a source observed with ALMA or the Planck satellite as well as for the interpretation of existing submillimetre observations obtained with other telescopes. DustPol allows the parameterisation of the maximum degree of polarisation and we find that, in a prestellar core, if there is depolarisation, this effect should happen at densities of 106 cm-3 or larger. We compare a model generated by DustPol with the observational polarisation data of the low-mass Class 0 object NGC 1333 IRAS 4A, finding that the total and the polarised emission are consistent.

  6. Adaptive Optics Imaging of Neptune and Titan with the W.M. Keck Telescope

    NASA Astrophysics Data System (ADS)

    Max, C.; Macintosh, B.; Gibbard, S.; Roe, H.; de Pater, I.; Ghez, A.; Acton, S.; Wizinowich, P.; Lai, O.

    1999-12-01

    We present near-IR images of Neptune and Titan with a resolution of 0.05 and 0.04 arc seconds respectively, obtained with the new adaptive optics (AO) system at the 10-m Keck II telescope. The resolution and contrast of these images allows us to fit radiative transfer atmospheric models including latitudinal and longitudinal variations. In the case of Neptune the images show both circumferential bands and bright cloud or storm features. We first model Neptune's clear atmosphere, un- contaminated by scattered light from the bright storms and bands. We can measure for the first time the precise infrared spatial extent of storm features and calculate their reflectance in broad-band and methane-absorption near-IR band-passes. These data allow us to model the changed haze distribution within the storm, relative to the clear atmosphere. In the case of Titan we use a radiative transfer model incorporating fractal haze properties, and are able to separate the contributions of Titan's atmosphere and surface to determine the optical depth of Titan's haze layer and to construct surface albedo maps. We find that Titan's trailing hemisphere is overall very dark, with a surface reflectance <0.05 consistent with the presence of solid or liquid hydrocarbons or perhaps very large-grained ice. The leading hemisphere is brighter, but with dark patches of very low albedo similar to the trailing hemisphere. These observations demonstrate that AO on an 8-10 meter telescope is a powerful new tool for the quantitative study of objects in the outer solar system, surpassing the resolution of the NICMOS instrument on the Hubble Space Telescope by a factor of 2-4. This research was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract W-7405-ENG-48.

  7. The European Extremely Large Telescope (E-ELT)

    NASA Astrophysics Data System (ADS)

    Gilmozzi, R.; Spyromilio, J.

    2007-03-01

    The ESO Council has authorised the E-ELT project to move to Phase B and approved the budget for the further design of the telescope and its instrumentation. In this article we present the activities and design concepts considered in the past year leading up to the decision of Council.

  8. Novel In-Space Manufacturing Concepts for the Development of Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Mooney, James T.; Reardon, Patrick; Gregory Don; Manning, Andrew; Blackmon, Jim; Howsman, Tom; Williams, Philip; Brantley, Whitt; Rakoczy, John; Herren, Kenneth

    2006-01-01

    There is a continuous demand for larger, lighter, and higher quality telescopes. Over the past several decades, we have seen the evolution from launchable 2 meter-class telescopes (such as Hubble), to today s demand for deployable 6 meter-class telescopes (such as JWST), to tomorrow s need for up to 150 meter-class telescopes. As the apertures continue to grow, it will become much more difficult and expensive to launch assembled telescope structures. To address this issue, we are seeing the emergence of new novel structural concepts, such as inflatable structures and membrane optics. While these structural concepts do show promise, it is very difficult to achieve and maintain high surface figure quality. Another potential solution to develop large space telescopes is to move the fabrication facility into space and launch the raw materials. In this paper we present initial in-space manufacturing concepts to enable the development of large telescopes. This includes novel approaches for the fabrication of both the optical elements and the telescope support structure. We will also discuss potential optical designs for large space telescopes and describe their relation to the fabrication methods. These concepts are being developed to meet the demanding requirements of DARPA s LASSO (Large Aperture Space Surveillance Optic) program which currently requires a 150 meter optical aperture with a 17 degree field of view.

  9. Innovative research in the design and operation of large telescopes for space: Aspects of giant telescopes in space

    NASA Technical Reports Server (NTRS)

    Angel, J. R. P.

    1985-01-01

    The capability and understanding of how to finish the reflector surfaces needed for large space telescopes is discussed. The technology for making very light glass substrates for mirrors is described. Other areas of development are in wide field imaging design for very fast primaries, in data analysis and retrieval methods for astronomical images, and in methods for making large area closely packed mosaics of solid state array detectors.

  10. Recent performance of the normal incident x-ray telescope with adaptive optics

    NASA Astrophysics Data System (ADS)

    Kitamoto, S.; Ishii, R.; Nukamori, S.; Imai, K.; Mochida, A.; Sato, S.; Ohgi, Y.; Yoshida, Y.; Hoshino, A.

    2016-09-01

    We report recent results of the performance measurement of our X-ray telescope with adaptive optics. The telescope is designed to use the 13.5nm EUV with the Mo/Si multilayers, making a normal incident optics. The primary mirror is 80mm in its diameter and the focal length of 2m. The deformable mirror is controlled by measuring a wave-front of an optical laser. Effects of a difference between the light paths from the reference and from an object are examined. The angular resolution is measured with optical light and we confirm almost diffraction limited resolution as well as its appropriate function as adaptive optics.

  11. First Light Adaptive Optics Images from the Keck II Telescope: A New Era of High Angular Resolution Imagery

    NASA Astrophysics Data System (ADS)

    Wizinowich, P.; Acton, D. S.; Shelton, C.; Stomski, P.; Gathright, J.; Ho, K.; Lupton, W.; Tsubota, K.; Lai, O.; Max, C.; Brase, J.; An, J.; Avicola, K.; Olivier, S.; Gavel, D.; Macintosh, B.; Ghez, A.; Larkin, J.

    2000-03-01

    Adaptive optics (AO) is a technology that corrects in real time for the blurring effects of atmospheric turbulence, in principle allowing Earth-bound telescopes to achieve their diffraction limit and to ``see'' as clearly as if they were in space. The power of AO using natural guide stars has been amply demonstrated in recent years on telescopes up to 3-4 m in diameter. The next breakthrough in astronomical resolution was expected to occur with the implementation of AO on the new generation of large, 8-10 m diameter telescopes. In this paper we report the initial results from the first of these AO systems, now coming on line on the 10 m diameter Keck II Telescope. The results include the highest angular resolution images ever obtained from a single telescope (0.022" and 0.040" at 0.85 and 1.65 μm wavelengths, respectively), as well as tests of system performance on three astronomical targets.

  12. Development of large aperture composite adaptive optics

    NASA Astrophysics Data System (ADS)

    Kmetik, Viliam; Vitovec, Bohumil; Jiran, Lukas; Nemcova, Sarka; Zicha, Josef; Inneman, Adolf; Mikulickova, Lenka; Pavlica, Richard

    2015-01-01

    Large aperture composite adaptive optics for laser applications is investigated in cooperation of Institute of Plasma Physic, Department of Instrumentation and Control Engineering FME CTU and 5M Ltd. We are exploring opportunity of a large-size high-power-laser deformable-mirror production using a lightweight bimorph actuated structure with a composite core. In order to produce a sufficiently large operational free aperture we are developing new technologies for production of flexible core, bimorph actuator and deformable mirror reflector. Full simulation of a deformable-mirrors structure was prepared and validated by complex testing. A deformable mirror actuation and a response of a complicated structure are investigated for an accurate control of the adaptive optics. An original adaptive optics control system and a bimorph deformable mirror driver were developed. Tests of material samples, components and sub-assemblies were completed. A subscale 120 mm bimorph deformable mirror prototype was designed, fabricated and thoroughly tested. A large-size 300 mm composite-core bimorph deformable mirror was simulated and optimized, fabrication of a prototype is carried on. A measurement and testing facility is modified to accommodate large sizes optics.

  13. Improved optical design for the Large Synoptic Survey Telescope (LSST)

    NASA Astrophysics Data System (ADS)

    Seppala, Lynn G.

    2002-12-01

    This paper presents an improved optical design for the LSST, an f/1.25 three-mirror telescope covering 3.0 degrees full field angle, with 6.9 m effective aperture diameter. The telescope operates at five wavelength bands spanning 386.5 nm to 1040 nm (B, V, R, I and Z). For all bands, 80% of the polychromatic diffracted energy is collected within 0.20 arc-seconds diameter. The reflective telescope uses an 8.4 m f/1.06 concave primary, a 3.4 m convex secondary and a 5.2 m concave tertiary in a Paul geometry. The system length is 9.2 m. A refractive corrector near the detector uses three fused silica lenses, rather than the two lenses of previous designs. Earlier designs required that one element be a vacuum barrier, but now the detector sits in an inert gas at ambient pressure, with the last lens serving as the gas barrier. Small adjustments lead to optimal correction at each band. Each filter has a different axial thickness, and the primary and tertiary mirrors are repositioned for each wavelength band. Features that simplify manufacturing include a flat detector, a far less aspheric convex secondary (10 μm from best fit sphere) and reduced aspheric departures on the lenses and tertiary mirror. Five aspheric surfaces, on all three mirrors and on two lenses, are used. The primary is nearly parabolic. The telescope is fully baffled so that no specularly reflected light from any field angle, inside or outside of the full field angle of 3.0 degrees, can reach the detector.

  14. Improved Optical Design for the Large Synoptic Survey Telescope (LSST)

    SciTech Connect

    Seppala, L

    2002-09-24

    This paper presents an improved optical design for the LSST, an fll.25 three-mirror telescope covering 3.0 degrees full field angle, with 6.9 m effective aperture diameter. The telescope operates at five wavelength bands spanning 386.5 nm to 1040 nm (B, V, R, I and Z). For all bands, 80% of the polychromatic diffracted energy is collected within 0.20 arc-seconds diameter. The reflective telescope uses an 8.4 m f/1.06 concave primary, a 3.4 m convex secondary and a 5.2 m concave tertiary in a Paul geometry. The system length is 9.2 m. A refractive corrector near the detector uses three fused silica lenses, rather than the two lenses of previous designs. Earlier designs required that one element be a vacuum barrier, but now the detector sits in an inert gas at ambient pressure. The last lens is the gas barrier. Small adjustments lead to optimal correction at each band. The filters have different axial thicknesses. The primary and tertiary mirrors are repositioned for each wavelength band. The new optical design incorporates features to simplify manufacturing. They include a flat detector, a far less aspheric convex secondary (10 {micro}m from best fit sphere) and reduced aspheric departures on the lenses and tertiary mirror. Five aspheric surfaces, on all three mirrors and on two lenses, are used. The primary is nearly parabolic. The telescope is fully baffled so that no specularly reflected light from any field angle, inside or outside of the full field angle of 3.0 degrees, can reach the detector.

  15. Tomographic control for wide field AO systems on extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Petit, C.; Conan, J.-M.; Fusco, T.; Neichel, B.

    2010-07-01

    We investigate in this article tomographic control using both Laser and Natural Guide Stars (LGS and NGS) in the particular framework of the European Extremely Large Telescope (E-ELT) Wide Field Adaptive Optics (WFAO) modules design. A similar global control strategy has been indeed derived for both the Laser Tomographic Adaptive Optics (LTAO) and Multi-Conjugate Adaptive Optics (MCAO) modules of the E-ELT, due to similar constraints. This control strategy leads in both cases to a split control of low order modes measured thanks to NGS and high order modes measured thanks to LGS. We investigate here this split tomographic control, compared to an optimal coupled solution. To support our analysis, a dedicated simulation code has been developed. Indeed, due to the huge complexity of the EELT, fast simulation tools must be considered to explore quickly the tomographic issues. We describe our control strategy which has lead to considering split tomographic control. First results on Tomography for E-ELT WFAO systems are then presented and discussed.

  16. Laboratory demonstration of a primary active mirror for space with the LATT: large aperture telescope technology

    NASA Astrophysics Data System (ADS)

    Briguglio, Runa; Biasi, Roberto; Gallieni, Daniele; Vettore, Christian; d'Amato, Francesco; Xompero, Marco; Arcidiacono, Carmelo; Lisi, Franco; Riccardi, Armando; Patauner, Christian; Lazzarini, Paolo; Tintori, Matteo; Duò, Fabrizio; Pucci, Mauro; Zuccaro Marchi, Alessandro; Maresi, Luca

    2016-07-01

    The LATT project is an ESA contract under TRP programme to demonstrate the scalability of the technology from ground-based adaptive mirrors to space active primary mirrors. A prototype spherical mirror based on a 40 cm diameter 1 mm thin glass shell with 19 contactless, voice-coil actuators and co-located position sensors have been manufactured and integrated into a final unit with an areal density lower than 20 kg/m2. Laboratory tests demonstrated the controllability with very low power budget and the survival of the fragile glass shell exposed to launch accelerations, thanks to an electrostatic locking mechanism; such achievements pushes the technology readiness level toward 5. With this prototype, the LATT project explored the feasibility of using an active and lightweight primary for space telescopes. The concept is attractive for large segmented telescopes, with surface active control to shape and co-phase them once in flight. In this paper we will describe the findings of the technological advances and the results of the environmental and optical tests.

  17. iLocater: a diffraction-limited Doppler spectrometer for the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Crepp, Justin R.; Crass, Jonathan; King, David; Bechter, Andrew; Bechter, Eric; Ketterer, Ryan; Reynolds, Robert; Hinz, Philip; Kopon, Derek; Cavalieri, David; Fantano, Louis; Koca, Corina; Onuma, Eleanya; Stapelfeldt, Karl; Thomes, Joseph; Wall, Sheila; Macenka, Steven; McGuire, James; Korniski, Ronald; Zugby, Leonard; Eisner, Joshua; Gaudi, B. S.; Hearty, Fred; Kratter, Kaitlin; Kuchner, Marc; Micela, Giusi; Nelson, Matthew; Pagano, Isabella; Quirrenbach, Andreas; Schwab, Christian; Skrutskie, Michael; Sozzetti, Alessandro; Woodward, Charles; Zhao, Bo

    2016-08-01

    We are developing a stable and precise spectrograph for the Large Binocular Telescope (LBT) named "iLocater." The instrument comprises three principal components: a cross-dispersed echelle spectrograph that operates in the YJ-bands (0.97-1.30 μm), a fiber-injection acquisition camera system, and a wavelength calibration unit. iLocater will deliver high spectral resolution (R 150,000-240,000) measurements that permit novel studies of stellar and substellar objects in the solar neighborhood including extrasolar planets. Unlike previous planet-finding instruments, which are seeing-limited, iLocater operates at the diffraction limit and uses single mode fibers to eliminate the effects of modal noise entirely. By receiving starlight from two 8.4m diameter telescopes that each use "extreme" adaptive optics (AO), iLocater shows promise to overcome the limitations that prevent existing instruments from generating sub-meter-per-second radial velocity (RV) precision. Although optimized for the characterization of low-mass planets using the Doppler technique, iLocater will also advance areas of research that involve crowded fields, line-blanketing, and weak absorption lines.

  18. Use of the moon and the large space telescope as an extrasolar planet detection system

    NASA Technical Reports Server (NTRS)

    Matloff, G. L.; Fennelly, A. J.

    1974-01-01

    Roman (1959), Spitzer (1962), and Huang (1973) have discussed photometric detection of extrasolar planets using a 3-m space telescope such as the Large Space Telescope (LST). A space telescope could be an extrasolar planet detection system if used in conjunction with an occulter placed 10,000 km in front of the telescope. The occulter would reduce the amount of light received from the star under observation. For a semi-infinite plane occulter 10,000 km in front of the telescope, Spitzer and Huang's results indicate that a Jupiter-like planet would be observed with a signal/noise of 1.00, for observations at 0.4 micron using a 3-m telescope like the LST.

  19. Nearby active galactic nuclei seen via adaptive optics at the Keck Telescope

    NASA Astrophysics Data System (ADS)

    Max, Claire

    2004-02-01

    In recent years it has become increasingly clear that mergers between galaxies play a critical role in galaxy evolution, in the formation of central black holes, and in the phenomena of active galactic nuclei (AGNs) and quasar activity. The advent of adaptive optics on the new generation of 6-10 m telescopes is making it possible to study nearby AGNs and merging galaxies with spatial resolutions of10 - 100 pc. In this talk I will describe and discuss observations of NGC 6240 and Cygnus A, archetypes of merging disk galaxies and of powerful radiogalaxies respectively. I will make use of infrared observations using the adaptive optics system on the 10-m Keck Telescope, as well as visible-light observations from the Hubble Space Telescope.

  20. Performance comparison of wavefront reconstruction and control algorithms for Extremely Large Telescopes.

    PubMed

    Montilla, I; Béchet, C; Le Louarn, M; Reyes, M; Tallon, M

    2010-11-01

    Extremely Large Telescopes (ELTs) are very challenging with respect to their adaptive optics (AO) requirements. Their diameters and the specifications required by the astronomical science for which they are being designed imply a huge increment in the number of degrees of freedom in the deformable mirrors. Faster algorithms are needed to implement the real-time reconstruction and control in AO at the required speed. We present the results of a study of the AO correction performance of three different algorithms applied to the case of a 42-m ELT: one considered as a reference, the matrix-vector multiply (MVM) algorithm; and two considered fast, the fractal iterative method (FrIM) and the Fourier transform reconstructor (FTR). The MVM and the FrIM both provide a maximum a posteriori estimation, while the FTR provides a least-squares one. The algorithms are tested on the European Southern Observatory (ESO) end-to-end simulator, OCTOPUS. The performance is compared using a natural guide star single-conjugate adaptive optics configuration. The results demonstrate that the methods have similar performance in a large variety of simulated conditions. However, with respect to system misregistrations, the fast algorithms demonstrate an interesting robustness.

  1. Life Cycle of a Large Telescope: the David Dunlap Observatory

    NASA Astrophysics Data System (ADS)

    Jarrell, Richard

    2009-01-01

    When it went into operation in 1935, the 74-inch reflector at the David Dunlap Observatory was the world's second largest and most sophisticated telescope. Designed specifically for stellar spectroscopy, almost all work performed with it until the early 1950s was limited to that specialty. Most University of Toronto staff were expected to contribute to the observatory's programme. However, as the staff expanded and newer research specialties were introduced, the telescope had to be refitted with new auxiliary equipment, or not be used at all. By the late 1960s, the observatory's night sky began to deteriorate due to light pollution from uncontrolled urban growth. While limited work could be performed into the 1990s, the telescope was no longer considered "large” far more powerful, versatile instruments at much superior sites were by then available. That Toronto astronomers had moved on can be demonstrated from their publication records. The end came in 2008 when the University of Toronto decided that the land's value could be used to support astronomical research in a broader sense. In response, the community, which had ignored the observatory for most of its history, and a few dissident astronomers, strongly defended its survival on a number of grounds. The narrative suggests a number of life-cycle stages: 1) maximum use of the instrument due to superior environmental and technical conditions, plus staff homogeneity; 2) application of new technologies to extend the instrument's capability in the face of diversifying research interests and decaying environmental factors; 3) fading value due to obsolescence and poor environmental factors; 4) death or metamorphosis (such as becoming an educational or historical institution). It appears that these phases apply to a number of historical cases. It is not clear, for the Dunlap Observatory, how the fourth phase will play out.

  2. Large Synoptic Survey Telescope: From Science Drivers to Reference Design

    DTIC Science & Technology

    2008-01-01

    such as Very Deep and Very Fast time domain surveys. We describe how the LSST science drivers led to these choices of system parameters . Key words...Sciences2 concluded that a dedicated ground-based wide-field imaging telescope with an effective aperture of 6–8 meters is a high priority for planetary ... parameters , as de- scribed in §2. A project status report and concluding remarks are presented in §3. For detailed and up-to- date information, please

  3. Technical description of the U.K. large telescope

    NASA Astrophysics Data System (ADS)

    Davies, Roger L.; Raybould, Keith

    1990-07-01

    The British astronomical community is currently engaged in the development of an 8-m aperture visible/IR telecope whose structure is based on the successful Herschel 4.2-m telescope. The primary mirror will be of meniscus type, with a 40:1 aspect ratio and active support; two secondaries will be used, of which the first (f/7) will furnish a corrected 40-arcmin field, while the second (f/35) can be chopped for use in the thermal IR. Enclosure design options under consideration encompass a carousel, a conventional hemispherical dome, and a lightweight octagonal enclosure.

  4. A purely reflective large wide-field telescope

    NASA Astrophysics Data System (ADS)

    Terebizh, V. Yu.

    2008-06-01

    Two versions of a fast, purely reflective Paul-Baker-type telescope are discussed, each with an 8.4-m aperture, 3° diameter flat field and f/1.25 focal ratio. The first version is based on a common, even asphere type of surface with zero conic constant. The primary and tertiary mirrors are 6th order aspheres, while the secondary mirror is an 8th order asphere (referred to here for brevity, as the 6/8/6 configuration). The D 80 diameter of a star image varies from 0″.18 on the optical axis up to 0″.27 at the edge of the field (9.3-13.5 μm). The second version of the telescope is based on a polysag surface type, which uses a polynomial expansion in the sag z, r^2 = 2R_0 z - left( {1 + b} right)z^2 + a_3 z^3 + a_4 z^3 + a_4 z^4 + ldots + a_N z^N instead of the common form of aspheric surface. This approach results in somewhat better images, with D 80 ranging from 0″.16 to 0″.23, using a lower-order 3/4/3 combination of powers for the mirror surfaces. An additional example with 3.5-m aperture, 3°.5 diameter flat field, and f/1.25 focal ratio featuring near-diffraction-limited image quality is also presented.

  5. Thirty Meter Telescope narrow-field infrared adaptive optics system real-time controller prototyping results

    NASA Astrophysics Data System (ADS)

    Smith, Malcolm; Kerley, Dan; Chapin, Edward L.; Dunn, Jennifer; Herriot, Glen; Véran, Jean-Pierre; Boyer, Corinne; Ellerbroek, Brent; Gilles, Luc; Wang, Lianqi

    2016-07-01

    Prototyping and benchmarking was performed for the Real-Time Controller (RTC) of the Narrow Field InfraRed Adaptive Optics System (NFIRAOS). To perform wavefront correction, NFIRAOS utilizes two deformable mirrors (DM) and one tip/tilt stage (TTS). The RTC receives wavefront information from six Laser Guide Star (LGS) Shack- Hartmann WaveFront Sensors (WFS), one high-order Natural Guide Star Pyramid WaveFront Sensor (PWFS) and multiple low-order instrument detectors. The RTC uses this information to determine the commands to send to the wavefront correctors. NFIRAOS is the first light AO system for the Thirty Meter Telescope (TMT). The prototyping was performed using dual-socket high performance Linux servers with the real-time (PREEMPT_RT) patch and demonstrated the viability of a commercial off-the-shelf (COTS) hardware approach to large scale AO reconstruction. In particular, a large custom matrix vector multiplication (MVM) was benchmarked which met the required latency requirements. In addition all major inter-machine communication was verified to be adequate using 10Gb and 40Gb Ethernet. The results of this prototyping has enabled a CPU-based NFIRAOS RTC design to proceed with confidence and that COTS hardware can be used to meet the demanding performance requirements.

  6. The Laser Guide Star System for Adaptive Optics at Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Hayano, Y.; Saito, Y.; Ito, M.; Saito, N.; Akagawa, K.; Takazawa, A.; Ito, M.; Wada, S.; Takami, H.; Iye, M.

    We report on the current status of developing the new laser guide star (LGS) system for the Subaru adaptive optics (AO) system. We have three major subsystems: the laser unit, the relay optical fiber and the laser launching telescope. A 4W-class all-solid-state 589nm laser has been developed as a light source for sodium laser guide star. We use two mode-locked Nd:YAG lasers operated at the wavelength of 1064nm and 1319nm to generate sum-frequency conversion into 589nm. The side-LD pumped configuration is used for the mode-locked Nd:YAG lasers. We have carefully considered the thermal lens effect in the cavity to achieve a high beam quality with TEM00; M2 = 1.06. The mode-locked frequency is selected at 143 MHz. We obtained the output powers of 16.5 W and 5.0 W at 1064nm and 1319 nm. Sum frequency generated by mixing two synchronized Nd:YAG mode-locked pulsed beams is precisely tuned to the sodium D2 line by thermal control of the etalon in the 1064nm Nd:YAG laser by observing the maximum fluorescence intensity of heated sodium vapor cell. The maximum output power at 589.159 nm reaches to 4.6 W using a PPMgOSLT crystal as a nonlinear optical crystal. And the output power can be maintained within a stability of +/- 1.2% for more than 3 days without optical damage. We developed a single-mode photonic crystal fiber (PCF) to relay the laser beam from laser clean room, in which the laser unit is located on the Nasmyth platform, to the laser launching telescope mounted behind the secondary mirror of Subaru Telescope. The photonic crystal fiber has solid pure silica core with the mode field diameter of 14 micron, which is relatively larger than that of the conventional step-index type single mode fiber. The length of the PCF is 35m and transmission loss due to the pure silica is 10dB/km at 589nm, which means PCF transmits 92% of the laser beam. We have preliminary achieved 75% throughput in total. Small mode-locked pulse width in time allows us to transmit the high

  7. Development of precision structure of a large-size space radio telescope

    NASA Astrophysics Data System (ADS)

    Astavin, A. S.; Kovalev, V. S.; Komaev, R. V.; Moisheev, A. A.; Tsvelev, V. M.; Serebrennikov, V. A.

    2015-12-01

    The paper presents methods for the design and engineering concepts, which made it possible to develop and manufacture the space radio telescope with a large size and high accuracy of the effective reflector area and focal assembly position.

  8. Photorefractive processing for large adaptive phased arrays

    NASA Astrophysics Data System (ADS)

    Weverka, Robert T.; Wagner, Kelvin; Sarto, Anthony

    1996-03-01

    An adaptive null-steering phased-array optical processor that utilizes a photorefractive crystal to time integrate the adaptive weights and null out correlated jammers is described. This is a beam-steering processor in which the temporal waveform of the desired signal is known but the look direction is not. The processor computes the angle(s) of arrival of the desired signal and steers the array to look in that direction while rotating the nulls of the antenna pattern toward any narrow-band jammers that may be present. We have experimentally demonstrated a simplified version of this adaptive phased-array-radar processor that nulls out the narrow-band jammers by using feedback-correlation detection. In this processor it is assumed that we know a priori only that the signal is broadband and the jammers are narrow band. These are examples of a class of optical processors that use the angular selectivity of volume holograms to form the nulls and look directions in an adaptive phased-array-radar pattern and thereby to harness the computational abilities of three-dimensional parallelism in the volume of photorefractive crystals. The development of this processing in volume holographic system has led to a new algorithm for phased-array-radar processing that uses fewer tapped-delay lines than does the classic time-domain beam former. The optical implementation of the new algorithm has the further advantage of utilization of a single photorefractive crystal to implement as many as a million adaptive weights, allowing the radar system to scale to large size with no increase in processing hardware.

  9. Optical design for the Narrow Field InfraRed Adaptive Optics System (NFIRAOS) Petite on the Thirty Meter Telescope

    SciTech Connect

    Bauman, B; Gavel, D; Dekany, R; Ellerbroek, B

    2005-08-02

    We describe an exploratory optical design for the Narrow Field InfraRed Adaptive Optics (AO) System (NFIRAOS) Petite, a proposed adaptive optics system for the Thirty Meter Telescope Project. NFIRAOS will feed infrared spectrograph and wide-field imaging instruments with a diffraction limited beam. The adaptive optics system will require multi-guidestar tomographic wavefront sensing and multi-conjugate AO correction. The NFIRAOS Petite design specifications include two small 60 mm diameter deformable mirrors (DM's) used in a woofer/tweeter or multiconjugate arrangement. At least one DM would be a micro-electromechanical system (MEMS) DM. The AO system would correct a 10 to 30 arcsec diameter science field as well as laser guide stars (LGS's) located within a 60 arcsec diameter field and low-order or tip/tilt natural guide stars (NGS's) within a 60 arcsec diameter field. The WFS's are located downstream of the DM's so that they can be operated in true closed-loop, which is not necessarily a given in extremely large telescope adaptive optics design. The WFS's include adjustable corrector elements which correct the static aberrations of the AO relay due to field position and LGS distance height.

  10. Adaptive optics real time processing design for the advanced technology solar telescope

    NASA Astrophysics Data System (ADS)

    Richards, Kit

    2012-07-01

    The four meter Advanced Technology Solar Telescope (ATST) adaptive optics (AO) system will require at least twenty-four times the real time processing power as the Dunn Solar Telescope AO system. An FPGA solution for ATST AO real time processing is being pursued instead of the parallel DSP approach used for the Dunn AO76 system. An analysis shows FPGAs will have lower latency and lower hardware cost than an equivalent DSP solution. Interfacing to the proposed high speed camera and the deformable mirror will be simpler and have lower latency than with DSPs. This paper will discuss the current design and progress toward implementing the FPGA solution.

  11. The tail wags the dog: managing large telescope construction projects with lagging requirements and creeping scope

    NASA Astrophysics Data System (ADS)

    Warner, Mark

    2014-08-01

    In a perfect world, large telescopes would be developed and built in logical, sequential order. First, scientific requirements would be agreed upon, vetted, and fully developed. From these, instrument designers would define their own subsystem requirements and specifications, and then flesh out preliminary designs. This in turn would then allow optic designers to specify lens and mirror requirements, which would permit telescope mounts and drives to be designed. Finally, software and safety systems, enclosures and domes, buildings, foundations, and infrastructures would be specified and developed. Unfortunately, the order of most large telescope projects is the opposite of this sequence. We don't live in a perfect world. Scientists usually don't want to commit to operational requirements until late in the design process, instrument designers frequently change and update their designs due to improving filter and camera technologies, and mount and optics engineers seem to live by the words "more" and "better" throughout their own design processes. Amplifying this is the fact that site construction of buildings and domes are usually the earliest critical path items on the schedule, and are often subject to lengthy permitting and environmental processes. These facility and support items therefore must quickly get underway, often before operational requirements are fully considered. Mirrors and mounts also have very long lead times for fabrication, which in turn necessitates that they are specified and purchased early. All of these factors can result in expensive and time-consuming change orders when requirements are finalized and/or shift late in the process. This paper discusses some of these issues encountered on large, multi-year construction projects. It also presents some techniques and ideas to minimize these effects on schedule and cost. Included is a discussion on the role of Interface Control Documents (ICDs), the importance (and danger) of making big

  12. Forecasting surface-layer atmospheric parameters at the Large Binocular Telescope site

    NASA Astrophysics Data System (ADS)

    Turchi, Alessio; Masciadri, Elena; Fini, Luca

    2017-04-01

    In this paper, we quantify the performance of an automated weather forecast system implemented on the Large Binocular Telescope (LBT) site at Mt Graham (Arizona) in forecasting the main atmospheric parameters close to the ground. The system employs a mesoscale non-hydrostatic numerical model (Meso-Nh). To validate the model, we compare the forecasts of wind speed, wind direction, temperature and relative humidity close to the ground with the respective values measured by instrumentation installed on the telescope dome. The study is performed over a large sample of nights uniformly distributed over 2 yr. The quantitative analysis is done using classical statistical operators [bias, root-mean-square error (RMSE) and σ] and contingency tables, which allows us to extract complementary key information, such as the percentage of correct detections (PC) and the probability of obtaining a correct detection within a defined interval of values (POD). The results of our study indicate that the model performance in forecasting the atmospheric parameters we have just cited are very good, in some cases excellent: RMSE for temperature is below 1°C, for relative humidity it is 14 per cent and for the wind speed it is around 2.5 m s-1. The relative error of the RMSE for wind direction varies from 9 to 17 per cent depending on the wind speed conditions. This work is performed in the context of the ALTA (Advanced LBT Turbulence and Atmosphere) Center project, whose final goal is to provide forecasts of all the atmospheric parameters and the optical turbulence to support LBT observations, adaptive optics facilities and interferometric facilities.

  13. Large aperture adaptive optics for intense lasers

    NASA Astrophysics Data System (ADS)

    Deneuville, François; Ropert, Laurent; Sauvageot, Paul; Theis, Sébastien

    2015-05-01

    ISP SYSTEM has developed a range of large aperture electro-mechanical deformable mirrors (DM) suitable for ultra short pulsed intense lasers. The design of the MD-AME deformable mirror is based on force application on numerous locations thanks to electromechanical actuators driven by stepper motors. DM design and assembly method have been adapted to large aperture beams and the performances were evaluated on a first application for a beam with a diameter of 250mm at 45° angle of incidence. A Strehl ratio above 0.9 was reached for this application. Simulations were correlated with measurements on optical bench and the design has been validated by calculation for very large aperture (up to Ø550mm). Optical aberrations up to Zernike order 5 can be corrected with a very low residual error as for actual MD-AME mirror. Amplitude can reach up to several hundreds of μm for low order corrections. Hysteresis is lower than 0.1% and linearity better than 99%. Contrary to piezo-electric actuators, the μ-AME actuators avoid print-through effects and they permit to keep the mirror shape stable even unpowered, providing a high resistance to electro-magnetic pulses. The MD-AME mirrors can be adapted to circular, square or elliptical beams and they are compatible with all dielectric or metallic coatings.

  14. The Gamma-ray Large Area Space Telescope (GLAST): Instrument Technology Development

    NASA Astrophysics Data System (ADS)

    Michelson, Peter F.; GLAST Collaboration

    1999-04-01

    The Gamma-ray Large Area Space Telescope, GLAST, is a satellite-based experiment under development to measure the cosmic gamma-ray flux in the energy range from 20 MeV to 300 GeV. The primary telescope for the mission is a pair-conversion telescope. The telescope design includes a precision tracker/converter section based on silicon-strip detectors, a CsI scintillating crystal calorimeter arranged in a hodoscopic configuration, an anticoincidence shield that is an array of plastic scintillator tiles read out with waveshifting optical fibers, and a powerful distributed data acquisition and triggering system. The design and expected performance of the telescope are presented along with results obtained from a high-energy beam test of a prototype.

  15. Fermi: The Gamma-Ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2014-01-01

    Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of an population of pulsars pulsing only in gamma rays; the detection of photons up to 10s of GeV from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as supersymmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

  16. Fermi: The Gamma-Ray Large Area Telescope

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2015-01-01

    Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of an population of pulsars pulsing only in gamma rays; the detection of photons up to 10s of GeV from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as supersymmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

  17. Fermi: The Gamma-Ray Large Area Telescope

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2014-01-01

    Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of an population of pulsars pulsing only in gamma rays; the detection of photons up to 10 seconds of gigaelectronvolts from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as super-symmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

  18. Fermi: The Gamma-Ray Large Area Telescope Mission Status

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2014-01-01

    Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of an population of pulsars pulsing only in gamma rays; the detection of photons up to 10s of GeV from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination of the diffuse gamma-ray emission with unprecedented accuracy and the constraints on phenomena such as supersymmetric dark-matter annihilations and exotic relics from the Big Bang. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies and the discovery of transient sources in our galaxy. In this talk I will describe the current status of the Fermi observatory and review the science highlights from Fermi.

  19. Large aperture freeform VIS telescope with smart alignment approach

    NASA Astrophysics Data System (ADS)

    Beier, Matthias; Fuhlrott, Wilko; Hartung, Johannes; Holota, Wolfgang; Gebhardt, Andreas; Risse, Stefan

    2016-07-01

    The development of smart alignment and integration strategies for imaging mirror systems to be used within astronomical instrumentation are especially important with regard to the increasing impact of non-rotationally symmetric optics. In the present work, well-known assembly approaches preferentially applied in the course of infrared instrumentation are transferred to visible applications and are verified during the integration of an anamorphic imaging telescope breadboard. The four mirror imaging system is based on a modular concept using mechanically fixed arrangements of each two freeform surfaces, generated by servo assisted diamond machining and corrected using Magnetorheological Finishing as a figuring and smoothing step. Surface testing include optical CGH interferometry as well as tactile profilometry and is conducted with respect to diamond milled fiducials at the mirror bodies. A strict compliance of surface referencing during all significant fabrication steps allow for an easy integration and direct measurement of the system's wave aberration after initial assembly. The achievable imaging performance, as well as influences of the tight tolerance budget and mid-spatial frequency errors, are discussed and experimentally evaluated.

  20. Formation Flying of Components of a Large Space Telescope

    NASA Technical Reports Server (NTRS)

    Mettler, Edward; Quadrelli, Marco; Breckenridge, William

    2009-01-01

    A conceptual space telescope having an aperture tens of meters wide and a focal length of hundreds of meters would be implemented as a group of six separate optical modules flying in formation: a primary-membrane-mirror module, a relay-mirror module, a focal-plane-assembly module containing a fast steering mirror and secondary and tertiary optics, a primary-mirror-figure-sensing module, a scanning-electron-beam module for controlling the shape of the primary mirror, and a sunshade module. Formation flying would make it unnecessary to maintain the required precise alignments among the modules by means of an impractically massive rigid structure. Instead, a control system operating in conjunction with a metrology system comprising optical and radio subsystems would control the firing of small thrusters on the separate modules to maintain the formation, thereby acting as a virtual rigid structure. The control system would utilize a combination of centralized- and decentralized-control methods according to a leader-follower approach. The feasibility of the concept was demonstrated in computational simulations that showed that relative positions could be maintained to within a fraction of a millimeter and orientations to within several microradians.

  1. PALM-3000: EXOPLANET ADAPTIVE OPTICS FOR THE 5 m HALE TELESCOPE

    SciTech Connect

    Dekany, Richard; Bouchez, Antonin; Baranec, Christoph; Hale, David; Zolkower, Jeffry; Henning, John; Croner, Ernest; McKenna, Dan; Hildebrandt, Sergi; Milburn, Jennifer; Roberts, Jennifer; Burruss, Rick; Truong, Tuan; Guiwits, Stephen; Angione, John; Trinh, Thang; Shelton, J. Christopher; Palmer, Dean; Troy, Mitchell; Tesch, Jonathan

    2013-10-20

    We describe and report first results from PALM-3000, the second-generation astronomical adaptive optics (AO) facility for the 5.1 m Hale telescope at Palomar Observatory. PALM-3000 has been engineered for high-contrast imaging and emission spectroscopy of brown dwarfs and large planetary mass bodies at near-infrared wavelengths around bright stars, but also supports general natural guide star use to V ≈ 17. Using its unique 66 × 66 actuator deformable mirror, PALM-3000 has thus far demonstrated residual wavefront errors of 141 nm rms under ∼1'' seeing conditions. PALM-3000 can provide phase conjugation correction over a 6.''4 × 6.''4 working region at λ = 2.2 μm, or full electric field (amplitude and phase) correction over approximately one-half of this field. With optimized back-end instrumentation, PALM-3000 is designed to enable 10{sup –7} contrast at 1'' angular separation, including post-observation speckle suppression processing. While continued optimization of the AO system is ongoing, we have already successfully commissioned five back-end instruments and begun a major exoplanet characterization survey, Project 1640.

  2. System concepts for a large UV/optical/IR telescope on the moon

    NASA Technical Reports Server (NTRS)

    Nein, Max E.; Davis, Billy

    1991-01-01

    To assess the systems and technological requirements for constructing lunar telescopes in conjunction with the buildup of a lunar base for scientific exploration and as a waypoint for travel to Mars, the NASA Marshall Space Flight Center conducted concept studies of a 16-m-aperture large lunar telescope (LLT) and a 4-m-aperture precursor telescope, both operating in the UV/visible/IR spectral region. The feasibility of constructing a large telescope on the lunar surface is assessed, and its systems and subsystems are analyzed. Telescope site selection, environmental effects, and launch and assembly scenarios are also evaluated. It is argued that key technical drivers for the LLT must be tested in situ by precursor telescopes to evaluate such areas as the operations and long-term reliability of active optics, radiation protection of instruments, lunar dust mitigation, and thermal shielding of the telescope systems. For a manned lunar outpost or an LLT to become a reality, a low-cost dependable transportation system must be developed.

  3. Requirements and concept design for large earth survey telescope for SEOS

    NASA Technical Reports Server (NTRS)

    Mailhot, P.; Bisbee, J.

    1975-01-01

    The efforts of a one year program of Requirements Analysis and Conceptual Design for the Large Earth Survey Telescope for the Synchronous Earth Observatory Satellite is summarized. A 1.4 meter aperture Cassegrain telescope with 0.6 deg field of view is shown to do an excellent job in satisfying the observational requirements for a wide range of earth resources and meteorological applications. The telescope provides imagery or thermal mapping in ten spectral bands at one time in a field sharing grouping of linear detector arrays. Pushbroom scanning is accomplished by spacecraft slew.

  4. Overview and Recent Accomplishments of Advanced Mirror Technology Development (AMTD) for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2013-01-01

    AMTD uses a science-driven systems engineering approach to define & execute a long-term strategy to mature technologies necessary to enable future large aperture space telescopes. Because we cannot predict the future, we are pursuing multiple technology paths including monolithic & segmented mirrors. Assembled outstanding team from academia, industry & government; experts in science & space telescope engineering. Derived engineering specifications from science measurement needs & implementation constraints. Maturing 6 critical technologies required to enable 4 to 8 meter UVOIR space telescope mirror assemblies for both general astrophysics & ultra-high contrast exoplanet imaging. AMTD achieving all its goals & accomplishing all its milestones.

  5. End-to-End Assessment of a Large Aperture Segmented Ultraviolet Optical Infrared (UVOIR) Telescope Architecture

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee; Bolcar, Matt; Liu, Alice; Guyon, Olivier; Stark,Chris; Arenberg, Jon

    2016-01-01

    Key challenges of a future large aperture, segmented Ultraviolet Optical Infrared (UVOIR) Telescope capable of performing a spectroscopic survey of hundreds of Exoplanets will be sufficient stability to achieve 10-10 contrast measurements and sufficient throughput and sensitivity for high yield Exo-Earth spectroscopic detection. Our team has collectively assessed an optimized end to end architecture including a high throughput coronagraph capable of working with a segmented telescope, a cost-effective and heritage based stable segmented telescope, a control architecture that minimizes the amount of new technologies, and an Exo-Earth yield assessment to evaluate potential performance.

  6. Toward Large-Area Sub-Arcsecond X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Aldcroft, Thomas L.; Allured, Ryan; Atkins, Carolyn; Burrows, David N.; Cao, Jian; Chalifoux, Brandon D.; Chan, Kai-Wing; Cotroneo, Vincenzo; Elsner, Ronald F.; Graham, Michael E.; Gubarev, Mikhail V.; Heilmann, Ralf K.; Johnson-Wilke, Raegan L.; Kilaru, Kiranmayee; Kolodziejczak, Jeffrey J.; McMuldroch, Stuart; Ramsey, Brian D.; Reid, Paul B.; Riveros, Raul E.; Roche, Jacqueline M.; Saha, Timo T.; Schattenburg, Mark L.; Schwartz, Daniel A.; Trolier-McKinstry, Susan E.; Ulmer, Melville P.; Vaynman, Semyon; Vikhlinin, Alexey; Wang, Xiaoli; Weisskopf, Martin C.; Wilke, Rudeger H. T.; Zhang, William W.

    2014-01-01

    The future of x-ray astronomy depends upon development of x-ray telescopes with larger aperture areas (>1 sq m) and finer angular resolution(<1).Combined with the special requirements of nested grazing incidence optics, the mass and envelope constraints of spaceborne telescopes render such advances technologically challenging. Achieving this goal will require precision fabrication, alignment, mounting, and assembly of large areas (>100 sq m) of lightweight (1 kg/sq m areal density) high quality mirrors-possibly entailing active (in-space adjustable) alignment and figure correction. This paper discusses relevant programmatic and technological issues and summarizes progress toward large area sub-arcsecond x-ray telescopes. Key words: X-ray telescopes, x-ray optics, active optics, electroactive devices, silicon mirrors, differential deposition, ion implantation.

  7. iLocater: A Diffraction-Limited Doppler Spectrometer for the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Crepp, Justin R.; Bechter, A.; Bechter, E.; Berg, M.; Carroll, J.; Collins, K.; Corpuz, T.; Ketterer, R.; Kielb, E.; Stoddard, R.; Eisner, J. A.; Gaudi, B. S.; Hinz, P.; Kratter, K. M.; Macela, G.; Quirrenbach, A.; Skrutskie, M. F.; Sozzetti, A.; Woodward, C. E.; Zhao, B.

    2014-01-01

    We are building an ultra-precise Doppler spectrometer for the Large Binocular Telescope (LBT) that operates at near-infrared wavelengths. The instrument, named iLocater, holds significant advantages over current and forth-coming Doppler designs. An R=110,000 spectrograph that operates in the Y-band, iLocater will receive a well-corrected beam from the LBT “extreme” adaptive optics system and use single-mode optical fibers to stabilize the instrument line spread function. With an input image 30 times smaller than comparable seeing-limited instruments (i.e., all Doppler radial velocity predecessors), iLocater will simultaneously achieve high spectral resolution, high spatial resolution, high throughput, and a compact optical design for low cost (affordable gratings). By working at the diffraction-limit, it is possible to circumvent, or ameliorate, many of the sources of noise common to seeing-limited spectrometers, including background contamination, thermal drifts, binary star interlopers, and pressure-induced changes in refractive index. Further, starlight received simultaneously from the LBT’s two separate telescope dishes may be used to monitor and remove internal systematic RV errors. iLocater will: identify "Earth-like" planets orbiting in the habitable-zone around nearby M-dwarf stars; perform the first systematic study of planet occurrence around binary stars as a function of their orbital separation; obtain the first spin-orbit orientation measurements of transiting terrestrial planets; and acquire essential follow-up observations for NASA's planned Transiting Exoplanet Survey Satellite (TESS) mission. In this poster, we present iLocater's design and science cases.

  8. Conceptual design of the scientific instrument arrangement for the large space telescope

    NASA Technical Reports Server (NTRS)

    Zurasky, J. L.

    1974-01-01

    A description of the scientific instrument arrangement for the large space telescope (LST) is given, with some of the rationale for selecting this concept. The first section of this report describes the basic configuration and was designed for an f/20 telescope focal plane. The subsequent LSTWG meeting held in November gave some redirection to the scientific requirements, and these changes are described in the section, Configuration Update.

  9. Low-cost Large Aperture Telescopes for Optical Communications

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid

    2006-01-01

    Low-cost, large-aperture optical receivers are required to form an affordable optical ground receiver network for laser communications. Among the ground receiver station's multiple subsystems, here, we only discuss the ongoing research activities aimed at reducing the cost of the large-size optics on the receiver. Experimental results of two different approaches for fabricating low-cost mirrors of wavefront quality on the order of 100-200X the diffraction limit are described. Laboratory-level effort are underway to improve the surface figure to better than 20X the diffraction limit.

  10. Robo-AO: The First Autonomous Laser Guide Star Adaptive Optics System for Small Telescopes

    NASA Astrophysics Data System (ADS)

    Riddle, Reed L.; Baranec, C.; Ramaprakash, A. N.; Law, N.; Tendulkar, S.; Kulkarni, S.; Bui, K.; Burse, M.; Chordia, P.; Das, H.; Dekany, R.; Kasliwal, M.; Ofek, E.; Zolkower, J.

    2011-01-01

    Robo-AO will be the first fully autonomous laser guide star adaptive optics and science system. Specifically designed to take advantage of small (1 to 3 meter) telescopes, Robo-AO will deliver high angular resolution science in the visible and near infrared for up to hundreds of targets per night. This will enable the exploration of science programs not practical for larger aperture adaptive optics systems. This presentation discusses the current status of the Robo-AO project, including the laboratory testbed, laser guide star facility and plans for a demonstration of the fully autonomous system next year.

  11. The Cosmology Large Angular Scale Surveyor (CLASS) Telescope Architecture

    NASA Technical Reports Server (NTRS)

    Chuss, David T.; Ali, Aamir; Amiri, Mandana; Appel, John W.; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Colazo, Felipe; Crowe, Erik; Denis, Kevin L.; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Hilton, Gene; Hinshaw, Gary F.; Huang, Caroline; Irwin, Kent; Jones, Glenn; Karakla, John; Kogut, Alan J.; Larson, David; Limon, Michele; Lowry, Lindsay; Marriage, Tobias; Mehrle, Nicholas; Stevenson, Thomas; Miller, Nathan J.; Moseley, Samuel H.; U-Yen, Kongpop; Wollack, Edward

    2014-01-01

    We describe the instrument architecture of the Johns Hopkins University-led CLASS instrument, a groundbased cosmic microwave background (CMB) polarimeter that will measure the large-scale polarization of the CMB in several frequency bands to search for evidence of inflation.

  12. Large filters for wide-field survey telescope LSST

    NASA Astrophysics Data System (ADS)

    Morgado, Nazario; Pinard, Laurent; Sassolas, Benoit; Flaminio, Raffaele; Forest, Daniéle; Lagrange, Bernard; Michel, Christophe; Antilogus, Pierre

    2012-09-01

    The LSST design foresees the use of six wide-band large optical filters that can alternatively be moved in front of the CCD camera. Each of the six filters has a different band-pass covering all the wavelengths from 300 nm to 1200 nm. The way to achieve this is to coat an optimized optical thin films stack on a filter substrate. Each filter requires a specific design using specific appropriate materials. The main characteristics of these filters, that constitute a real technological challenge, are: their relatively large size - their radii of curvature (about 5.6 m) that represent a sagitta of 12,5 mm that increases the uniformity complexity, the large rejection band requirements with transmission lower than 0.01 % out of the band and a transmission of 95 % over the band-pass. This paper proposes to show the problematic and the results obtained at LMA (Laboratoire des Matériaux Avancés-FRANCE) to the purpose of realizing these filters using the IBS (Ion Beam Sputtering) deposition technique. The results obtained with High-Pass/Low-Pass structures will be presented. Experimental results will be shown concerning the R-band filter (552-691 nm). An overview of the work to be done to realize transmittance map over large filters will be given.

  13. Adaptive momentum management for large space structures

    NASA Technical Reports Server (NTRS)

    Hahn, E.

    1987-01-01

    Momentum management is discussed for a Large Space Structure (LSS) with the structure selected configuration being the Initial Orbital Configuration (IOC) of the dual keel space station. The external forces considered were gravity gradient and aerodynamic torques. The goal of the momentum management scheme developed is to remove the bias components of the external torques and center the cyclic components of the stored angular momentum. The scheme investigated is adaptive to uncertainties of the inertia tensor and requires only approximate knowledge of principle moments of inertia. Computational requirements are minimal and should present no implementation problem in a flight type computer and the method proposed is shown to be effective in the presence of attitude control bandwidths as low as .01 radian/sec.

  14. Chinese Large Optic/IR Telescope (LOT): planning for the next decade

    NASA Astrophysics Data System (ADS)

    Cui, Xiang-qun; Zhu, Yong-tian

    2016-08-01

    Chinese astronomical community has suggested to construct a high resolution precision and wide field survey of universal optical / infrared telescope, suitable for a wide range of cutting-edge scientific research subject. The telescope diameter is 12 meters, and it is composed of 84 pieces of hexagonal mirrors. After the completion, it could be a world's largest telescope. Its wide field survey function will be work together with the 30 meters telescope in the near future on the observation of complementary. The telescope optical system adopted innovative design ideas, its multiple focuses can achieve rapid switching; its atmospheric dispersion corrector lens-prism can correct aberration also, and with the advantage of simple structure; two layers of Nasmyth platform can be placed more scientific instruments. LAMOST, a Chinese large spectrum survey telescope has been built and put into operation many years, it has successfully developed the two segmented optical mirrors and one of them is with deformation of thin mirror active optical technology, as well as the batch grinding hexagonal off-axis mirror technology developed in recent years, for construction of the 12 meters telescope laid a good technical foundation.

  15. Extremely large telescope: a twenty-five meter aperture for the twenty-first century

    NASA Astrophysics Data System (ADS)

    Bash, Frank N.; Sebring, Thomas A.; Ray, Frank B.; Ramsey, Lawrence W.

    1997-03-01

    The 10-meter class Hobby-Eberly telescope (HET), now nearing completion, provides technology for optical Arecibo-type telescopes which can be extrapolated to even larger apertures. Utilizing a fixed elevation angle and a spherical segmented primary mirror provides cost effective and pragmatic solutions to mirror mounting and fabrication. Arecibo-type tracking implies a greatly reduced tracking mass and no change to the gravity vector for the primary mirror. Such a telescope can address 70 percent of the available sky and exhibit optical quality easily sufficient for effective spectroscopy and photometry. The extremely large telescope takes advantage of several key engineering approaches demonstrated by the HET project to achieve a cost comparable to similarly-sized radio rather than optical telescopes. These engineering approaches include: bolted pre-manufactured primary mirror truss, factory manufactured geodesic enclosure dome, air bearing rotation of primary mirror, tracker, and dome systems directly on concrete piers, and tracking via a hexapod system. Current estimates put the cost of the ELT at $200 million for a 25-meter aperture utilizing a 33-meter primary mirror array. Construction of the ELT would provide the astronomy community with an optical telescope nearly an order of magnitude larger than even the largest telescopes in operation or under construction today.

  16. Prime focus architectures for large space telescopes: reduce surfaces to save cost

    NASA Astrophysics Data System (ADS)

    Breckinridge, J. B.; Lillie, C. F.

    2016-07-01

    Conceptual architectures are now being developed to identify future directions for post JWST large space telescope systems to operate in the UV Optical and near IR regions of the spectrum. Here we show that the cost of optical surfaces within large aperture telescope/instrument systems can exceed $100M/reflection when expressed in terms of the aperture increase needed to over come internal absorption loss. We recommend a program in innovative optical design to minimize the number of surfaces by considering multiple functions for mirrors. An example is given using the Rowland circle imaging spectrometer systems for UV space science. With few exceptions, current space telescope architectures are based on systems optimized for ground-based astronomy. Both HST and JWST are classical "Cassegrain" telescopes derived from the ground-based tradition to co-locate the massive primary mirror and the instruments at the same end of the metrology structure. This requirement derives from the dual need to minimize observatory dome size and cost in the presence of the Earth's 1-g gravitational field. Space telescopes, however function in the zero gravity of space and the 1- g constraint is relieved to the advantage of astronomers. Here we suggest that a prime focus large aperture telescope system in space may have potentially have higher transmittance, better pointing, improved thermal and structural control, less internal polarization and broader wavelength coverage than Cassegrain telescopes. An example is given showing how UV astronomy telescopes use single optical elements for multiple functions and therefore have a minimum number of reflections.

  17. Isoplanatic patch considerations for solar telescope multi-conjugate adaptive optics

    NASA Astrophysics Data System (ADS)

    Beckers, Jacques M.

    2014-08-01

    I compare recent site surveys for the future large 4-meter solar and 30-meter nighttime telescopes at the nearby Haleakala and Mauna Kea sites respectively. They show that the outstanding early morning image quality at the solar site corresponds indeed to that observed at the late night one at the nighttime site. That confirms the notion that daytime solar site heating only shows itself later in the morning. The nighttime survey includes observations of the refractive index structure function Cn 2(h) to high altitudes from which the radius of the isoplanatic patch (Ɵ0) can be determined. At zenith (ζ = 00) it equals 2.5 arcsec at 500 nm wavelength. For the early morning (best) seeing at the solar site, which occurs at ζsun = 750 and the cos1.6(ζ) dependence of Θ0,that means an extremely small Ɵ0 (0.26 arcsec). Such small values compromise Adaptive Optics (AO) solar correlation wavefront sensing for which areas are needed equal to about 8"× 8" I suggest options for measuring Cn2(h), and therefore Ɵ0, during the day. These make use of the solar image as well as of daytime images of bright stars and planets. Some use the MASS technique on stars; some use the SHABAR technique using very large detector baselines on the Sun and shorter baselines on planets. It is suggested that these Cn2(h) measurements are made also during regular solar observations. In that way optimal solar observations can be planned using real-time Ɵ0 observations by image selection and optimization of the MCAO configuration.

  18. PILOT—a Pathfinder for an International Large Optical Telescope in Antarctica

    NASA Astrophysics Data System (ADS)

    Ashley, M. C. B.; Burton, M. G.; Lawrence, J. S.; Storey, J. W. V.

    2006-08-01

    PILOT is a proposed 2.4 metre optical/IR telescope, designed to take advantage of the extraordinarily good observing conditions on the high plateau of Antarctica. The superb seeing and low infrared backgrounds will allow PILOT to outperform telescopes of 2-3 times the diameter at a mid-latitude site. PILOT is large enough to undertake important science, while small enough to act as a low-cost low-risk technology demonstrator for the next generation of large optical/IR telescopes in Antarctica. Future facilities could include the proposed 8.4 metre off-axis LAPCAT telescope, that would be competitive with ELTs in its ability to directly image extra-solar planets. PILOT is envisaged as an international collaboration. It is hoped that Australia will fund the telescope, with instruments, logistics and other aspects of the project contributed by international partners. A detailed science case for PILOT has been published, and a number of design studies for the telescope have been completed or are under way.

  19. Development of Large-Aperture, Light-Weight Fresnel Lenses for Gossamer Space Telescopes

    SciTech Connect

    Sham, D; Hyde, R; Weisberg, A; Early, J; Rushford, M; Britten, J

    2002-04-29

    In order to examine more distant astronomical objects, with higher resolution, future space telescopes require objectives with significantly larger aperture than presently available. NASA has identified a progression in size from the 2.4m aperture objective currently used in the HUBBLE space telescope[l,2], to 25m and greater in order to observe, e.g., extra-solar planets. Since weight is a crucial factor for any object sent into space, the relative weight of large optics over a given area must be reduced[3]. The areal mass density of the primary mirror for the Hubble space telescope is {approx}200 kg/m{sup 2}. This is expected to be reduced to around 15 kg/m{sup 2} for the successor to Hubble--the next generation space telescope (NGST)[4]. For future very large aperture telescopes needed for extra-solar planet detection, the areal mass density must be reduced even further. For example, the areal mass density goal for the Gossamer space telescopes is < 1 kg/m{sup 2}. The production of lightweight focusing optics at >10m size is also an enabling technology for many other applications such as Earth observation, power beaming, and optical communications.

  20. NPT: a large-aperture telescope for high dynamic range astronomy

    NASA Astrophysics Data System (ADS)

    Joseph, Robert D.; Kuhn, Jeff R.; Tokunaga, Alan T.; Coulter, Roy; Ftaclas, Christo; Graves, J. Elon; Hull, Charles L.; Jewitt, D.; Mickey, Donald L.; Moretto, Gilberto; Neill, Doug; Northcott, Malcolm J.; Roddier, Claude A.; Roddier, Francois J.; Siegmund, Walter A.; Owen, Tobias C.

    2000-06-01

    All existing night-time astronomical telescopes, regardless of aperture, are blind to an important part of the universe - the region around bright objects. Technology now exist to build an unobscured 6.5 m aperture telescope which will attain coronagraphic sensitivity heretofore unachieved. A working group hosted by the University of Hawaii Institute for Astronomy has developed plans for a New Planetary Telescope which will permit astronomical observations which have never before ben possible. In its narrow-field mode the off-axis optical design, combined with adaptive optics, provides superb coronagraphic capabilities, and a very low thermal IR background. These make it ideal for studies of extra-solar planets and circumstellar discs, as well as for general IR astronomy. In its wide-field mode the NPT provides a 2 degree diameter field for surveys of Kuiper Belt Objects and Near-Earth Objects, surveys central to current intellectual interests in solar system astronomy.

  1. An efficient pipeline wavefront phase recovery for the CAFADIS camera for extremely large telescopes.

    PubMed

    Magdaleno, Eduardo; Rodríguez, Manuel; Rodríguez-Ramos, José Manuel

    2010-01-01

    In this paper we show a fast, specialized hardware implementation of the wavefront phase recovery algorithm using the CAFADIS camera. The CAFADIS camera is a new plenoptic sensor patented by the Universidad de La Laguna (Canary Islands, Spain): international patent PCT/ES2007/000046 (WIPO publication number WO/2007/082975). It can simultaneously measure the wavefront phase and the distance to the light source in a real-time process. The pipeline algorithm is implemented using Field Programmable Gate Arrays (FPGA). These devices present architecture capable of handling the sensor output stream using a massively parallel approach and they are efficient enough to resolve several Adaptive Optics (AO) problems in Extremely Large Telescopes (ELTs) in terms of processing time requirements. The FPGA implementation of the wavefront phase recovery algorithm using the CAFADIS camera is based on the very fast computation of two dimensional fast Fourier Transforms (FFTs). Thus we have carried out a comparison between our very novel FPGA 2D-FFTa and other implementations.

  2. An Efficient Pipeline Wavefront Phase Recovery for the CAFADIS Camera for Extremely Large Telescopes

    PubMed Central

    Magdaleno, Eduardo; Rodríguez, Manuel; Rodríguez-Ramos, José Manuel

    2010-01-01

    In this paper we show a fast, specialized hardware implementation of the wavefront phase recovery algorithm using the CAFADIS camera. The CAFADIS camera is a new plenoptic sensor patented by the Universidad de La Laguna (Canary Islands, Spain): international patent PCT/ES2007/000046 (WIPO publication number WO/2007/082975). It can simultaneously measure the wavefront phase and the distance to the light source in a real-time process. The pipeline algorithm is implemented using Field Programmable Gate Arrays (FPGA). These devices present architecture capable of handling the sensor output stream using a massively parallel approach and they are efficient enough to resolve several Adaptive Optics (AO) problems in Extremely Large Telescopes (ELTs) in terms of processing time requirements. The FPGA implementation of the wavefront phase recovery algorithm using the CAFADIS camera is based on the very fast computation of two dimensional fast Fourier Transforms (FFTs). Thus we have carried out a comparison between our very novel FPGA 2D-FFTa and other implementations. PMID:22315523

  3. Fractal iterative method for fast atmospheric tomography on extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Tallon, Michel; Tallon-Bosc, Isabelle; Béchet, Clémentine; Momey, Fabien; Fradin, Marie; Thiébaut, Éric

    2010-07-01

    A challenge of adaptive optics (AO) on Extremely Large Telescopes (ELTs) is to overcome the difficulty of solving a huge number of equations in real time, especially when atmospheric tomography is involved. This is particularly the case for multi-conjugate or multi-objects AO systems. In addition, the quality of the wavefront estimation is crucial to optimize the performances of the future systems in a situation where measurements are missing and noises are correlated. The Fractal Iterative Method has been introduced as a fast iterative algorithm for minimum variance wavefront reconstruction and control on ELTs. This method has been successfully tested on Classical Single Conjugate AO systems on Octopus numerical simulator at ESO. But the minimum variance approach is expected to be mostly useful with atmospheric tomography. We present the first results obtained with FrIM in the context of atmospheric tomography. We recall the principle of the algorithm and we summarize the formalism used for modeling the measurements obtained from laser guide stars that entail spot elongation and tip/tilt indetermination, mixed with low order measurements from natural guide stars. We show the respective effects of tip/tilt indetermination, spot elongation, unseen modes on various configurations, as well as the usefulness of priors and correct noise models in the reconstruction. This analysis is essential for balancing the various errors that combine in a quite complex way and to optimize the configuration of the future AO systems for specific science cases and instrument requirements.

  4. An Analysis Methodology for the Gamma-ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    Morris, Robin D.; Cohen-Tanugi, Johann

    2004-01-01

    The Large Area Telescope (LAT) instrument on the Gamma Ray Large Area Space Telescope (GLAST) has been designed to detect high-energy gamma rays and determine their direction of incidence and energy. We propose a reconstruction algorithm based on recent advances in statistical methodology. This method, alternative to the standard event analysis inherited from high energy collider physics experiments, incorporates more accurately the physical processes occurring in the detector, and makes full use of the statistical information available. It could thus provide a better estimate of the direction and energy of the primary photon.

  5. Advanced UVOIR Mirror Technology Development (AMTD) for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Smith, W. Scott; Mosier, Gary; Abplanalp, Laura; Arnold, William

    2014-01-01

    ASTRO2010 Decadal stated that an advanced large-aperture ultraviolet, optical, near-infrared (UVOIR) telescope is required to enable the next generation of compelling astrophysics and exoplanet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. AMTD builds on the state of art (SOA) defined by over 30 years of monolithic & segmented ground & space-telescope mirror technology to mature six key technologies. AMTD is deliberately pursuing multiple design paths to provide the science community with op-tions to enable either large aperture monolithic or segmented mirrors with clear engineering metrics traceable to science requirements.

  6. Science data quality assessment for the Large Synoptic Survey Telescope

    NASA Astrophysics Data System (ADS)

    Shaw, Richard A.; Levine, Deborah; Axelrod, Timothy; Laher, Russ R.; Mannings, Vince G.

    2010-07-01

    LSST will have a Science Data Quality Assessment (SDQA) subsystem for the assessment of the data products that will be produced during the course of a 10 yr survey. The LSST will produce unprecedented volumes of astronomical data as it surveys the accessible sky every few nights. The SDQA subsystem will enable comparisons of the science data with expectations from prior experience and models, and with established requirements for the survey. While analogous systems have been built for previous large astronomical surveys, SDQA for LSST must meet a unique combination of challenges. Chief among them will be the extraordinary data rate and volume, which restricts the bulk of the quality computations to the automated processing stages, as revisiting the pixels for a post-facto evaluation is prohibitively expensive. The identification of appropriate scientific metrics is driven by the breadth of the expected science, the scope of the time-domain survey, the need to tap the widest possible pool of scientific expertise, and the historical tendency of new quality metrics to be crafted and refined as experience grows. Prior experience suggests that contemplative, off-line quality analyses are essential to distilling new automated quality metrics, so the SDQA architecture must support integrability with a variety of custom and community-based tools, and be flexible to embrace evolving QA demands. Finally, the time-domain nature of LSST means every exposure may be useful for some scientific purpose, so the model of quality thresholds must be sufficiently rich to reflect the quality demands of diverse science aims.

  7. An overview and the current status of instrumentation at the Large Binocular Telescope Observatory

    NASA Astrophysics Data System (ADS)

    Wagner, R. Mark; Edwards, Michelle L.; Kuhn, Olga; Thompson, David; Veillet, Christian

    2014-07-01

    An overview of instrumentation for the Large Binocular Telescope (LBT) is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (24' × 24') mosaic CCD imagers at the prime focus, and the Multi-Object Double Spectrograph (MODS), a pair of dual-beam blue-red optimized long-slit spectrographs mounted at the left and right direct F/15 Gregorian foci incorporating multiple slit masks for multi-object spectroscopy over a 6' field and spectral resolutions of up to 2000. Infrared instrumentation includes the LBT Near-IR Spectrometer (LUCI), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at the left and right front-bent F/15 Gregorian foci and designed for seeing-limited (FOV: 4' × 4') imaging, long-slit spectroscopy, and multi-object spectroscopy utilizing cooled slit masks and diffraction limited (FOV: 0'.5 x 0'.5) imaging and long-slit spectroscopy. Strategic instruments under development that can utilize the full 23 m baseline of the LBT include an interferometric cryogenic beam combiner with near-infrared and thermal-infrared instruments for Fizeau imaging and nulling interferometry (LBTI) and an optical bench near- infrared beam combiner utilizing multi-conjugate adaptive optics for high angular resolution and sensitivity (LINC-NIRVANA). LBTI is currently undergoing commissioning and performing science observations on the LBT utilizing the installed adaptive secondary mirrors in both single-sided and two-sided beam combination modes. In addition, a fiber-fed bench spectrograph (PEPSI) capable of ultra high resolution spectroscopy and spectropolarimetry (R = 40,000-300,000) will be available as a principal investigator instrument. Installation and testing of the bench spectrograph will begin in July 2014. Over the past four years the LBC pair, LUCI1, and MODS1 have been commissioned and are now scheduled for routine partner science observations. Both LUCI2 and MODS2 passed their laboratory

  8. Co-Phasing the Large Binocular Telescope:. [Status and Performance of LBTI-PHASECam

    NASA Technical Reports Server (NTRS)

    Defrere, D.; Hinz, P.; Downey, E.; Ashby, D.; Bailey, V.; Brusa, G.; Christou, J.; Danchi, W. C.; Grenz, P.; Hill, J. M.; Hoffmann, W. F.; Leisenring, J.; Lozi, J.; McMahon, T.; Mennesson, B.; Millan-Gabet, R.; Montoya, M.; Powell, K.; Skemer, A.; Vaitheeswaran, V.; Vaz, A.; Veillet, C.

    2014-01-01

    The Large Binocular Telescope Interferometer is a NASA-funded nulling and imaging instrument designed to coherently combine the two 8.4-m primary mirrors of the LBT for high-sensitivity, high-contrast, and high-resolution infrared imaging (1.5-13 micrometer). PHASECam is LBTI's near-infrared camera used to measure tip-tilt and phase variations between the two AO-corrected apertures and provide high-angular resolution observations. We report on the status of the system and describe its on-sky performance measured during the first semester of 2014. With a spatial resolution equivalent to that of a 22.8-meter telescope and the light-gathering power of single 11.8-meter mirror, the co-phased LBT can be considered to be a forerunner of the next-generation extremely large telescopes (ELT).

  9. Integration and mechanical interfacing of very large instruments at UKIRT and JCMT telescopes

    NASA Astrophysics Data System (ADS)

    Chylek, Tomas; Shutt, Dean J.

    2003-02-01

    The progress in development of advanced instrumentation for IR and submillimeter telescopes during the past decades is bringing new structural and logistics challenges to engineers at both the UKIRT and JCMT telescopes. These facilities were designed for instruments much smaller, lighter, and less complex than those currently under construction. This paper describes the ongoing structural changes to the design of both telescopes and innovative approaches to the mechanical interfacing of extremely large and heavy instruments. The design changes and handling schemes these large and unwieldy instruments require would be unthinkable without utilization of advanced 3-D computer modeling and finite element analysis. Examples will be given of particular challenges associated with the handling and interfacing of existing instruments at both facilities as well as the difficulties presented by new generation instrumentation currently under development. The importance of involving facility engineers as early as the conceptual stages of new instrument design and development will be demonstrated.

  10. The Advanced Technology Large Aperture Space Telescope (ATLAST): Science Drivers and Technology Developments

    NASA Technical Reports Server (NTRS)

    Postman, Marc; Brown, Tom; Sembach, Kenneth; Giavalisco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Phillip; Tumlinson, Jason; Mountain, Matt; Soummer, Remi; Hyde, Tupper

    2011-01-01

    The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including "Is there life elsewhere in the Galaxy?" We present a range of science drivers and the resulting performance requirements for ATLAST (8 to 16 milliarcsecond angular resolution, diffraction limited imaging at 0.5 m wavelength, minimum collecting area of 45 square meters, high sensitivity to light wavelengths from 0.1 m to 2.4 m, high stability in wavefront sensing and control). We also discuss the priorities for technology development needed to enable the construction of ATLAST for a cost that is comparable to current generation observatory-class space missions. Keywords: Advanced Technology Large-Aperture Space Telescope (ATLAST); ultraviolet/optical space telescopes; astrophysics; astrobiology; technology development.

  11. Reliability-centered maintenance for ground-based large optical telescopes and radio antenna arrays

    NASA Astrophysics Data System (ADS)

    Marchiori, G.; Formentin, F.; Rampini, F.

    2014-07-01

    In the last years, EIE GROUP has been more and more involved in large optical telescopes and radio antennas array projects. In this frame, the paper describes a fundamental aspect of the Logistic Support Analysis (LSA) process, that is the application of the Reliability-Centered Maintenance (RCM) methodology for the generation of maintenance plans for ground-based large optical telescopes and radio antennas arrays. This helps maintenance engineers to make sure that the telescopes continue to work properly, doing what their users require them to do in their present operating conditions. The main objective of the RCM process is to establish the complete maintenance regime, with the safe minimum required maintenance, carried out without any risk to personnel, telescope and subsystems. At the same time, a correct application of the RCM allows to increase the cost effectiveness, telescope uptime and items availability, and to provide greater understanding of the level of risk that the organization is managing. At the same time, engineers shall make a great effort since the initial phase of the project to obtain a telescope requiring easy maintenance activities and simple replacement of the major assemblies, taking special care on the accesses design and items location, implementation and design of special lifting equipment and handling devices for the heavy items. This maintenance engineering framework is based on seven points, which lead to the main steps of the RCM program. The initial steps of the RCM process consist of: system selection and data collection (MTBF, MTTR, etc.), definition of system boundaries and operating context, telescope description with the use of functional block diagrams, and the running of a FMECA to address the dominant causes of equipment failure and to lay down the Critical Items List. In the second part of the process the RCM logic is applied, which helps to determine the appropriate maintenance tasks for each identified failure mode. Once

  12. Designs for a large-aperture telescope to map the CMB 10× faster.

    PubMed

    Niemack, Michael D

    2016-03-01

    Current large-aperture cosmic microwave background (CMB) telescopes have nearly maximized the number of detectors that can be illuminated while maintaining diffraction-limited image quality. The polarization-sensitive detector arrays being deployed in these telescopes in the next few years will have roughly 10⁴ detectors. Increasing the mapping speed of future instruments by at least an order of magnitude is important to enable precise probes of the inflationary paradigm in the first fraction of a second after the big bang and provide strong constraints on cosmological parameters. The CMB community has begun planning a next generation "Stage IV" CMB project that will be comprised of multiple telescopes with between 10⁵-10⁶ detectors to pursue these goals. This paper introduces the new crossed Dragone telescope and receiver optics designs that increase the usable diffraction-limited field-of-view, and therefore the mapping speed, by an order of magnitude compared to the upcoming generation of large-aperture instruments. Polarization systematics and engineering considerations are presented, including a preliminary receiver model to demonstrate that these designs will enable high efficiency illumination of >10⁵ detectors in a next generation CMB telescope.

  13. Preliminary use of nematic liquid crystal adaptive optics with a 2.16-meter reflecting telescope.

    PubMed

    Cao, Zhaoliang; Mu, Quanquan; Hu, Lifa; Li, Dayu; Peng, Zenghui; Liu, Yonggang; Xuan, Li

    2009-02-16

    A nematic liquid crystal adaptive optics system (NLC AOS) was assembled for a 2.16-m telescope to correct for atmospheric turbulence. LC AOS was designed and optimized with Zemax optical software. Second, an adaptive correction experiment was performed in the laboratory to test the performance of the NLC AOS. After the correction, the peak to valley (PV) and root mean square (RMS) of the wavefront were down to 0.2 lambda (lambda=633 nm) and 0.05 lambda, respectively. Finally, the star of Pollux (beta Gem) was tracked using the 2.16-m Reflecting Telescope, and real time correction of the atmospheric turbulence was performed with the NLC AOS. After the adaptive correction, the average PV and RMS of the wavefront were reduced from 11 lambda and 2.5 lambda to 2.3 lambda and 0.6 lambda, respectively. Although the intensity distribution of the beta Gem was converged and its peak was sharp, a halo still existed around the peak. These results indicated that the NLC AOS only partially corrected the vertical atmospheric turbulence. The limitations of our NLC AOS are discussed and some proposals are made.

  14. Modelling, simulation and testing of an optomechatronics design of a large radio telescope

    NASA Astrophysics Data System (ADS)

    Duan, B. Y.; Qiu, Y. Y.; Su, Y. X.; Wang, W. L.; Nan, R. D.; Peng, B.

    An innovative design for a feed support structure for the next generation large radio telescope, based on the idea of integrating mechanical, electronic and optical technologies (OPTOMECHATRONICS), is considered. Theoretical analyses and simulations are carried out. A 5 m experimental model is built to demonstrate the idea.

  15. Results of the JOSE site evaluation project for adaptive optics at the William Herschel Telescope

    NASA Astrophysics Data System (ADS)

    Wilson, R.

    1998-11-01

    Results are presented from a long-term study of the seeing properties at the William Herschel Telescope on La Palma. The measurements have been made over a two-year period using a Shack-Hartmann wavefront sensor equipped with high frame-rate CCD camera. The aim of the campaign is to characterize those aspects of the seeing relevant to the design and performance of astronomical adaptive optical systems for the WHT. Statistical results are presented for the value of Fried's parameter, power spectra of Zernike mode coefficients, isoplanatism and the outer scale of turbulence.

  16. Adaptive Optics Observations of Arcturus using the Mount Wilson 100 Inch Telescope

    NASA Astrophysics Data System (ADS)

    Turner, Nils H.; ten Brummelaar, Theo A.; Mason, Brian D.

    1999-05-01

    Upon inspection of the multiple-star results in the Hipparcos catalog, the flag for entry number 69673 particularly stands out; it is Arcturus, for which no companion has been reported previously. The Hipparcos companion is reported to be at a separation of 0.255"+/-0.039" with a magnitude difference in a broadband filter (peaked near 460 nm) of 3.33+/-0.31. We present recent results using the natural guide star adaptive optics system on the Mount Wilson 100 inch telescope showing Arcturus to be a single star.

  17. Object-oriented software design for the Mt. Wilson 100-inch Hooker telescope adaptive optics system

    NASA Astrophysics Data System (ADS)

    Schneider, Thomas G.

    2000-06-01

    The object oriented software design paradigm has been instrumented in the development of the Adoptics software used in the Hooker telescope's ADOPT adaptive optics system. The software runs on a Pentium-class PC host and eight DSP processors connected to the host's motherboard bus. C++ classes were created to implement most of the host software's functionality, with the object oriented features of inheritance, encapsulation and abstraction being the most useful. Careful class design at the inception of the project allowed for the rapid addition of features without comprising the integrity of the software. Base class implementations include the DSP system, real-time graphical displays and opto-mechanical actuator control.

  18. PEPSI: The high-resolution échelle spectrograph and polarimeter for the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Strassmeier, K. G.; Ilyin, I.; Järvinen, A.; Weber, M.; Woche, M.; Barnes, S. I.; Bauer, S.-M.; Beckert, E.; Bittner, W.; Bredthauer, R.; Carroll, T. A.; Denker, C.; Dionies, F.; DiVarano, I.; Döscher, D.; Fechner, T.; Feuerstein, D.; Granzer, T.; Hahn, T.; Harnisch, G.; Hofmann, A.; Lesser, M.; Paschke, J.; Pankratow, S.; Plank, V.; Plüschke, D.; Popow, E.; Sablowski, D.

    2015-05-01

    PEPSI is the bench-mounted, two-arm, fibre-fed and stabilized Potsdam Echelle Polarimetric and Spectroscopic Instrument for the 2×8.4 m Large Binocular Telescope (LBT). Three spectral resolutions of either 43 000, 120 000 or 270 000 can cover the entire optical/red wavelength range from 383 to 907 nm in three exposures. Two 10.3k×10.3k CCDs with 9-μm pixels and peak quantum efficiencies of 94-96 % record a total of 92 échelle orders. We introduce a new variant of a wave-guide image slicer with 3, 5, and 7 slices and peak efficiencies between 92-96 %. A total of six cross dispersers cover the six wavelength settings of the spectrograph, two of them always simultaneously. These are made of a VPH-grating sandwiched by two prisms. The peak efficiency of the system, including the telescope, is 15 % at 650 nm, and still 11 % and 10 % at 390 nm and 900 nm, respectively. In combination with the 110 m2 light-collecting capability of the LBT, we expect a limiting magnitude of ≈ 20th mag in V in the low-resolution mode. The R = 120 000 mode can also be used with two, dual-beam Stokes IQUV polarimeters. The 270 000-mode is made possible with the 7-slice image slicer and a 100-μm fibre through a projected sky aperture of 0.74 arcsec, comparable to the median seeing of the LBT site. The 43 000-mode with 12-pixel sampling per resolution element is our bad seeing or faint-object mode. Any of the three resolution modes can either be used with sky fibers for simultaneous sky exposures or with light from a stabilized Fabry-Pérot étalon for ultra-precise radial velocities. CCD-image processing is performed with the dedicated data-reduction and analysis package PEPSI-S4S. Its full error propagation through all image-processing steps allows an adaptive selection of parameters by using statistical inferences and robust estimators. A solar feed makes use of PEPSI during day time and a 500-m feed from the 1.8 m VATT can be used when the LBT is busy otherwise. In this paper, we

  19. Research on the support structure of the primary mirror of large-aperture telescope

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Zhang, Jingxu

    2007-12-01

    Large-aperture telescope can be used in surveying battlefield, researching landform, searching object, real-time monitoring, imaging, detecting and identifying spatial targets and so on. A large-aperture telescope for achieving high resolution power is designed to monitor spatial target and image in real time. Real-time monitoring plays an important role in military conflicts. The orbit parameter of object, quantity, geometrical shape parameter and so on can be obtained by detect spatial target. With the development of optical technology, people require larger aperture in optics-electronic (O-E) system. By increasing optical aperture, the ability of collecting light and resolution power in the system can be enhanced. But the support structure of the primary mirror of large-aperture telescope will be a very difficult problem. With the increase of primary mirror aperture, the weight of the primary mirror will become larger than before. The root mean square (rms) of the primary mirror is affected by many factors, such as deadweight, deformation of heat, environment and so on. Due to the primary mirror of telescope is an important component of telescope system. By reducing the weight of primary mirror, precision of the system is ensured. During the designing phase, one can consider the supporting project of the primary mirror synthetically and analyze it roundly according to technical requirement of optical system and the effect factors. The final structural design can be reasonable. In an astronomical telescope, the surface of reflector is an important part for collecting dark radiation of celestial bodies. Its surface shape will have an effect on collecting efficiency of telescope radiant energy directly. So the rms must be very high. Optical system of large aperture, small wavelength and small focus can receive maximal light intensity. For ground-based optical astronomical telescope, the design proposed in the paper can satisfy the requirement of the possible

  20. Status of GLAST, the Gamma-ray Large-area Space Telescope

    SciTech Connect

    Rochester, L.; /SLAC

    2005-12-14

    GLAST is a satellite-based observatory consisting of the Large-Area Telescope (LAT), a modular 4 x 4-tower pair-conversion telescope with a field-of-view greater than 2 steradians, capable of measuring gamma-ray energies in the range 20 MeV to 300 GeV, and the GLAST Burst Monitor (GBM), a set of NaI and BGO detectors covering 8 steradians and sensitive to photons with energies between 10 keV and 25 MeV, allowing for correlative observations of transient events. The observatory is currently being constructed and is scheduled to be launched in August 2007.

  1. Efficient method for the reduction of large piston errors in segmented-mirror telescopes.

    PubMed

    Chanan, Gary; Pintó, Agustí

    2004-06-01

    Phase discontinuity sensing (PDS) is one of two successful approaches to segment phasing that are currently in use at the Keck telescopes, but it has only a limited capture range. We describe and present numerical simulations of a broadband version of the current (narrowband) PDS algorithm that can extend the capture range from 0.4 to 40 microns. Like the original algorithm, the new broadband PDS algorithm requires no special-purpose hardware but only a high-resolution area detector operating in the 2-3-microns range. The potential application of this algorithm to extremely large telescopes is also discussed.

  2. A STUDY OF CEPHEIDS IN M81 WITH THE LARGE BINOCULAR TELESCOPE (EFFICIENTLY CALIBRATED WITH HUBBLE SPACE TELESCOPE)

    SciTech Connect

    Gerke, J. R.; Kochanek, C. S.; Stanek, K. Z.; Prieto, J. L.; Macri, L. M.

    2011-12-20

    We identify and phase a sample of 107 Cepheids with 10 days < P < 100 days in M81 using the Large Binocular Telescope and calibrate their B, V, and I mean magnitudes with archival Hubble Space Telescope (HST) data. The use of a ground-based telescope to identify and phase the Cepheids and HST only for the final calibration reduces the demand on this highly oversubscribed spacecraft by nearly an order of magnitude and yields period-luminosity (PL) relations with dispersions comparable to the best LMC samples. We fit the sample using the OGLE-II LMC PL relations and are unable to find a self-consistent distance for different band combinations or radial locations within M81. We can do so after adding a radial dependence to the PL zero point that corresponds to a luminosity dependence on metallicity of {gamma}{sub {mu}} = -0.56 {+-} 0.36 mag dex{sup -1}. We find marginal evidence for a shift in color as a function of metallicity, distinguishable from the effects of extinction, of {gamma}{sub 2} = +0.07 {+-} 0.03 mag dex{sup -1}. We find a distance modulus for M81, relative to the LMC, of {mu}{sub M81} - {mu}{sub LMC} = 9.39 {+-} 0.14 mag, including uncertainties due to the metallicity corrections. This corresponds to a distance to M81 of 3.6 {+-} 0.2 Mpc, assuming an LMC distance modulus of 18.41 mag. We carry out a joint analysis of M81 and NGC 4258 Cepheids and simultaneously solve for the distance of M81 relative to NGC 4258 and the metallicity corrections. Given the current data, the uncertainties of such joint fits are dominated by the relative metallicities and the abundance gradients rather than by measurement errors of the Cepheid magnitudes or colors. We find {mu}{sub M81} - {mu}{sub LMC} = 9.40{sup +0.15}{sub -0.11} mag, {mu}{sub N4258} - {mu}{sub LMC} = 11.08{sup +0.21}{sub -0.17} mag, and {mu}{sub N4258} - {mu}{sub M81} = 1.68 {+-} 0.08 mag and metallicity effects on luminosity and color of {gamma}{sub {mu}} = -0.62{sup +0.31}{sub -0.35} mag dex{sup -1} and

  3. Adaptive Control Techniques for Large Space Structures.

    DTIC Science & Technology

    1986-09-15

    Adaptive Systems: A Ji . Fixed-Point Analysis", submitted, IEEE Trans. on Circuits and Systems; Special Issue on Adaptive Systems, Sept. 1987. I.M.Y...Shaped Cost Functionals: Extensions of LQG Methods," *.. AIAA J. of Guidance and Control, pp. 529-535, Nov-Dec. 1980. [81 C.A. Desoer , R.W. Liu, J. Murray...for Parameter Conver- gence in Adaptive Control," Memo No. UCB/ERL M84/25, Univ. of California, Berke- ley, 1984. [19] C.A. Desoer and M. Vidyasagar

  4. Adaptive Control Techniques for Large Space Structures

    DTIC Science & Technology

    1989-01-06

    Point Analy- sis", submitted, IEEE Trans. on Circuits and Systems; Special Issue on Adaptive Systems, Sept. 1987. I.M.Y. Mareels, R.R. Bitmead, M. Gevers...adaptive system with unmodelled dynamics," Proc. IFAC Workshop on Adaptive Systems, San Francisco, CA. C.A. Desoer , R.W. Liu, J. Murray and R. Sacks...June 1980. C.A. Desoer and M. Vidyasagar, Feedback Systems: Input-Output Properties, Academic Press, * 1975. J.C. Doyle and G. Stein (1981

  5. Correlation of Fermi Large Area Telescope sources with the 20-GHz Australia Telescope Compact Array radio survey

    NASA Astrophysics Data System (ADS)

    Ghirlanda, G.; Ghisellini, G.; Tavecchio, F.; Foschini, L.

    2010-09-01

    We cross-correlate the Fermi 11-month survey (1FGL) catalogue with the 20-GHz Australia Telescope Compact Array (AT20G) radio survey catalogue composed of 5890 sources at declination < 0°. Among the 738 Fermi sources distributed in the southern sky, we find 230 highly probable candidate counterparts in the AT20G survey. Of these, 222 are already classified in the Fermi one-year Large Area Telescope (LAT) active galactic nucleus (AGN) catalogue (1LAC) as blazars [either flat spectrum radio quasars (FSRQs) or BL Lacertae objects (BL Lacs)], AGNs or sources of unknown class but with an associated counterpart, while eight are new associations. By studying the γ-ray and radio properties of these associations, we find a correlation between the γ-ray flux (above 100 MeV) and the 20-GHz flux density. This correlation is more than 3σ statistically significant, both for the population of BL Lacs and for FSRQs considered separately. We also find that the radio counterparts associated with the Fermi sources have, on average, flat radio spectra between 5 and 20 GHz and that Fermi γ-ray sources are not preferentially associated with `ultra-inverted spectrum' radio sources. For two of the eight new associations, we build the broad-band spectral energy distribution combining Fermi, Swift and radio observations. One of these two sources is identified with the high-redshift FSRQ Swift J1656.3-3302 (z = 2.4) and we classify the other source as a candidate new FSRQ. We also study the brightest radio source of the 46 associations without an optical classification and classify it as a new BL Lac candidate `twin' of the prototypical BL Lac OJ 287 if its redshift is larger, z ~ 0.4.

  6. Testbed for an adaptive secondary mirror of 1.8m telescope

    NASA Astrophysics Data System (ADS)

    Fan, Xinlong; Guan, Chunlin; Rao, Changhui

    2010-11-01

    Testbed for an adaptive secondary mirror of 1.8m telescope is a system, which originates from Simpson-Oland-Meckel method. The testbed is composed of Hartmann-Shack (H-S) wavefront sensor, Hindle element and analysis element. Light from H-S wavefront sensor passes through the Hindle element and reflects off of the adaptive secondary mirror. It then is reflected by the concave surface of the Hindle element. After reflecting off of the adaptive secondary mirror again, it passes through the Hindle element and return to the H-S wavefront sensor. A beam splitter is placed between H-S wavefront sensor and Hindle element to reflect part of the output light to analysis element. The testbed is a low cost simple system that allows testing the convex hyperboloid adaptive secondary mirror. It also could be used to calibrate the adaptive secondary mirror as well as investigating higher performance control loops. Optical setup design, tolerance of fabrication, alignment and material asymmetry are presented in this paper.

  7. A secure and reliable monitor and control system for remote observing with the Large Millimeter Telescope

    NASA Astrophysics Data System (ADS)

    Wallace, Gary; Souccar, Kamal; Malin, Daniella

    2004-09-01

    Remote access to telescope monitor and control capabilities necessitates strict security mechanisms to protect the telescope and instruments from malicious or unauthorized use, and to prevent data from being stolen, altered, or corrupted. The Large Millimeter Telescope (LMT) monitor and control system (LMTMC) utilizes the Common Object Request Broker Architecture (CORBA) middleware technology to connect remote software components. The LMTMC provides reliable and secure remote observing by automatically generating SSLIOP enabled CORBA objects. TAO, the ACE open source Object Request Broker (ORB), now supports secure communications by implementing the Secure Socket Layer Inter-ORB Protocol (SSLIOP) as a pluggable protocol. This capability supplies the LMTMC with client and server authentication, data integrity, and encryption. Our system takes advantage of the hooks provided by TAO SSLIOP to implement X.509 certificate based authorization. This access control scheme includes multiple authorization levels to enable granular access control.

  8. End-to-end assessment of a large aperture segmented ultraviolet optical infrared (UVOIR) telescope architecture

    NASA Astrophysics Data System (ADS)

    Feinberg, Lee; Rioux, Norman; Bolcar, Matthew; Liu, Alice; Guyon, Olivier; Stark, Chris; Arenberg, Jon

    2016-07-01

    Key challenges of a future large aperture, segmented Ultraviolet Optical Infrared (UVOIR) Telescope capable of performing a spectroscopic survey of hundreds of Exoplanets will be sufficient stability to achieve 10^-10 contrast measurements and sufficient throughput and sensitivity for high yield exo-earth spectroscopic detection. Our team has collectively assessed an optimized end to end architecture including a high throughput coronagraph capable of working with a segmented telescope, a cost-effective and heritage based stable segmented telescope, a control architecture that minimizes the amount of new technologies, and an exo-earth yield assessment to evaluate potential performance. These efforts are combined through integrated modeling, coronagraph evaluations, and exo-earth yield calculations to assess the potential performance of the selected architecture. In addition, we discusses the scalability of this architecture to larger apertures and the technological tall poles to enabling these missions.

  9. End-to-End Assessment of a Large Aperture Segmented Ultraviolet Optical Infrared (UVOIR) Telescope Architecture

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee; Rioux, Norman; Bolcar, Matthew; Liu, Alice; Guyon, Oliver; Stark, Chris; Arenberg, Jon

    2016-01-01

    Key challenges of a future large aperture, segmented Ultraviolet Optical Infrared (UVOIR) Telescope capable of performing a spectroscopic survey of hundreds of Exoplanets will be sufficient stability to achieve 10^-10 contrast measurements and sufficient throughput and sensitivity for high yield Exo-Earth spectroscopic detection. Our team has collectively assessed an optimized end to end architecture including a high throughput coronagraph capable of working with a segmented telescope, a cost-effective and heritage based stable segmented telescope, a control architecture that minimizes the amount of new technologies, and an Exo-Earth yield assessment to evaluate potential performance. These efforts are combined through integrated modeling, coronagraph evaluations, and Exo-Earth yield calculations to assess the potential performance of the selected architecture. In addition, we discusses the scalability of this architecture to larger apertures and the technological tall poles to enabling it.

  10. The achromatic design of an atmospheric dispersion corrector for extremely large telescopes.

    PubMed

    Bahrami, Mehdi; Goncharov, Alexander V

    2011-08-29

    For off-zenith observations with ground-based astronomical telescopes, the effect of atmospheric dispersion relative to diffraction on image size increases with telescope diameter. Correction of atmospheric dispersion in extremely large telescopes (ELTs) might become critical. A common solution for ELTs is to use linear atmospheric dispersion correctors (ADCs). In spite of their simplicity, the intrinsic chromatic aberrations of linear ADCs could render diffraction-limited imaging impossible when used in a fast focus. The chromatic problems of the linear ADC in ELTs can be resolved by replacing the linear ADC by the achromatic ADC designs presented here, which provide diffraction-limited image quality and offer several opto-mechanical advantages over linear ADCs.

  11. Imaging Extra-Solar Planets with an Ultra-Large Space Telescope

    NASA Technical Reports Server (NTRS)

    Taylor, Charles R.

    1998-01-01

    NASA's Origins Program is directed toward two main goals: Imaging of galactic evolution in the early universe, and searching for planets orbiting nearby stars. The Next-Generation Space Telescope (NGST), operating at low temperature with an 8-m aperture, is well designed to meet the first goal. The goal of imaging planets orbiting nearby stars is more problematic. One line of investigation has been the ULTIMA concept (Ultra-Large Telescope, Integrated Missions in Astronomy). In this report, I will lay out the resolution requirements for telescopes to achieve the imaging of extrasolar planets, and describe a modeling tool created to investigate the requirements for imaging a planet when it is very near a much brighter star.

  12. Serviceable Large Low Cost/Mass Infrared 4 Kelvin Telescope Passively Cooled

    NASA Astrophysics Data System (ADS)

    Tenerelli, Domenick; Tolomeo, J.; Klavins, A.; Putnam, D.

    2012-05-01

    An innovative space telescope concept was studied for the New Millenium program for ST6. The telescope called a Dual Anamorphic Reflector Telescope (DART) features two single curvature monolith parabolic surfaces. The telescope system personifies simplicity which extrapolates to low cost and mass. We at Lockheed Martin have implemented this design in two large prototypes that demonstrate imaging in the IR without the use of corrective optics as well as demonstrate the mass scaling advantageous of this architecture. A serviceable deployment concept is described which will enable apertures greater than 10m with areal density less than 10 kg/m2 to be realized for space applications. Because of the overall simplicity of the architecture the instrument section is easily replaceable when new detector technology is developed. In addition the simplicity of the overall architecture allows the system to assembled on the International Space Station (ISS). Anti sun pointing, low conductance support structure and deployable sun shade made of multiple deployable shields in an open groove configuration maintains telescope temperatures near 4K with minimal gradients

  13. Current status of the laser guide star adaptive optics system for Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Hayano, Yutaka; Takami, Hideki; Guyon, Olivier; Oya, Shin; Hattori, Masayuki; Saito, Yoshihiko; Watanabe, Makoto; Murakami, Naoshi; Minowa, Yosuke; Ito, Meguru; Colley, Stephen; Eldred, Michael; Golota, Taras; Dinkins, Matthew; Kashikawa, Nobunari; Iye, Masanori

    2008-07-01

    The current status and recent results, since last SPIE conference at Orlando in 2006, for the laser guide star adaptive optics system for Subaru Telescope is presented. We had a first light using natural guide star and succeed to launch the sodium laser beam in October 2006. The achieved Strehl ratio on the 10th magnitude star was around 0.5 at K band. We confirmed that the full-width-half-maximum of the stellar point spread function is smaller than 0.1 arcsec even at the 0.9 micrometer wavelehgth. The size of the artificial guide star by the laser beam tuned at the wavelength of 589 nm was estimated to be 10 arcsec. The obtained blurred artificial guide star is caused by the wavefront error on the laser launching telescope. After the first light and first launch, we found that we need to modify and to fix the components, which are temporarily finished. Also components, which were postponed to fabricate after the first light, are required to build newly. All components used by the natural guide star adaptive optics system are finalized recently and we are ready to go on the sky. Next engineering observation is scheduled in August, 2008.

  14. Technology gap assessment for a future large-aperture ultraviolet-optical-infrared space telescope

    NASA Astrophysics Data System (ADS)

    Bolcar, Matthew R.; Balasubramanian, Kunjithapatham; Crooke, Julie; Feinberg, Lee; Quijada, Manuel; Rauscher, Bernard J.; Redding, David; Rioux, Norman; Shaklan, Stuart; Stahl, H. Philip; Stahle, Carl M.; Thronson, Harley

    2016-10-01

    The Advanced Technology Large Aperture Space Telescope (ATLAST) team identified five key technology areas to enable candidate architectures for a future large-aperture ultraviolet/optical/infrared (LUVOIR) space observatory envisioned by the NASA Astrophysics 30-year roadmap, "Enduring Quests, Daring Visions." The science goals of ATLAST address a broad range of astrophysical questions from early galaxy and star formation to the processes that contributed to the formation of life on Earth, combining general astrophysics with direct-imaging and spectroscopy of habitable exoplanets. The key technology areas are internal coronagraphs, starshades (or external occulters), ultra-stable large-aperture telescope systems, detectors, and mirror coatings. For each technology area, we define best estimates of required capabilities, current state-of-the-art performance, and current technology readiness level (TRL), thus identifying the current technology gap. We also report on current, planned, or recommended efforts to develop each technology to TRL 5.

  15. Wheel drives for large telescopes: save the cost and keep the performance over hydrostatic bearings

    NASA Astrophysics Data System (ADS)

    Campbell, Marvin F.

    2014-07-01

    The use of steel wheels on steel tracks has been around since steel was invented, and before that it was iron wheels on iron tracks. Not to be made obsolete by the passage of time, this approach for moving large objects is still valid, even optimal, but the detailed techniques for achieving high performance and long life have been much improved. The use of wheel-and-track designs has been very popular in radio astronomy for the largest of the large radio telescopes (RT), including such notables as the 305m Arecibo RT, the 100m telescopes at Effelsberg, Germany (at 3600 tonnes) and the Robert C. Byrd, Greenbank Telescope (GBT, 7600 tonnes) at Greenbank, West Virginia. Of course, the 76m Lovell Telescope at Jodrell Bank is the grandfather of all large aperture radio telescopes that use wheel drives. Smaller sizes include NRAO's Very Long Baseline Array (VLBA) telescopes at 25m and others. Wheel drives have also been used on large radars of significance such as the 410 tonne Ground Based Radar-Prototype (GBR-P) and the 150 foot (45.7m) Altair Radar, and the 2130 tonne Sea Based X-Band Radar (SBX). There are also many examples of wheel driven communications antennas of 18 meters and larger. All of these instruments have one thing in common: they all use steel wheels that run in a circle on one or more flat, level, steel tracks. This paper covers issues related to designing for wheel driven systems. The intent is for managing motion to sub arc-second levels, and for this purpose it is primary for the designer to manage measurement and alignment errors, and to establish repeatability through dimensional control, structural and drive stiffness management, adjustability and error management. In a practical sense, there are very few, if any, fabricators that can machine structural and drive components to sufficiently small decimal places to matter. In fact, coming within 2-3 orders of magnitude of the precision needed is about the best that can be expected. Further, it is

  16. Ten years maintaining MACAO-VLTI units in operation in the Very Large Telescope at Paranal Observatory

    NASA Astrophysics Data System (ADS)

    Salgado, F.; Hudepohl, G.

    2016-07-01

    More than 10 years have already passed since the first Multiple Application Curvature Adaptive Optics (MACAO) facilities got the first light in UT2 the 18th of April, 2003, in the Very Large Telescope (VLT) at Paranal Observatory. The achievable image sharpness of a ground-based telescope is normally limited by the effect of atmospheric turbulence. However, with Adaptive Optics (AO) techniques, this major drawback can be overcome so that the telescope produces images that are as sharp as theoretically possible, i.e., as if they were taken from space. [1] The intention of this document is summarize in few pages some highlights related with the activities needed to keep MACAO units in operation. Some statistics of problems based in Action Remedy tool is included, showing how through these years the number of problems has been reduced, even when there are still some unsolved ones. Some lessons have been learned and there are others one to learn. Corrective and predictive maintenance performed are shown too like the current measurements, transfer functions measurements, thermography pictures, health checks measuring interaction matrix and flat vectors to detect dead APDs or short circuits in the DM, etc. Some forced interventions are included as well like the removal of the cabinets from Coude rooms to avoid that acoustic noise and vibrations perturb the operations, the deformable mirrors reached by cooling leaks and a mirror that got rusty are shown too. Well knowledge of the system, good interaction between different disciplines groups to perform corrective and preventive maintenance seems to be key aspects of keeping it under control and operative during all these years leading to this good result.

  17. Large Space Telescopes Using Fresnel Lens for Power Beaming, Astronomy and Sail Missions

    SciTech Connect

    Early, J T

    2002-10-15

    The concept of using Fresnel optics as part of power beaming, astronomy or sail systems has been suggested by several authors. The primary issues for large Fresnel optics are the difficulties in fabricating these structures and deploying them in space and for astronomy missions the extremely narrow frequency range of these optics. In proposals where the telescope is used to transmit narrow frequency laser power, the narrow bandwidth has not been an issue. In applications where the optic is to be used as part of a telescope, only around 10{sup -5} to limited frequency response of a Fresnel optic is addressed by the use of a corrective optic that will broaden the frequency response of the telescope by three or four orders of magnitude. This broadening will dramatically increase the optical power capabilities of the system and will allow some spectroscopy studies over a limited range. Both the fabrication of Fresnel optics as large as five meters and the use of corrector optics for telescopes have been demonstrated at LLNL. For solar and laser sail missions the use of Fresnel amplitude zone plates made of very thin sail material is also discussed.

  18. GLAST: Exploring Nature's Highest Energy Processes with the Gamma-ray Large Area Space Telescope

    NASA Technical Reports Server (NTRS)

    Digel, Seth; Myers, J. D.; White, Nicholas E. (Technical Monitor)

    2001-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) is an international and multi-agency space mission that will study the cosmos in the energy range 10 keV-300 GeV. Several successful exploratory missions in gamma-ray astronomy led to the Energetic Gamma Ray Experiment Telescope (EGRET) instrument on the Compton Gamma Ray Observatory (CGRO). Launched in 1991, EGRET made the first complete survey of the sky in the 30 MeV-10 GeV range. EGRET showed the high-energy gamma-ray sky to be surprisingly dynamic and diverse, with sources ranging from the sun and moon to massive black holes at large redshifts. Most of the gamma-ray sources detected by EGRET remain unidentified. In light of the discoveries with EGRET, the great potential of the next generation gamma-ray telescope can be appreciated. GLAST will have an imaging gamma-ray telescope vastly more capable than instruments flown previously, as well as a secondary instrument to augment the study of gamma-ray bursts. The main instrument, the Large Area Telescope (LAT), will have superior area, angular resolution, field of view, and deadtime that together will provide a factor of 30 or more advance in sensitivity, as well as provide capability for study of transient phenomena. The GLAST Burst Monitor (GBM) will have a field of view several times larger than the LAT and will provide spectral coverage of gamma-ray bursts that extends from the lower limit of the LAT down to 10 keV. The basic parameters of the GBM are compared to those of the Burst and Transient Source Experiment (BATSE) instrument on CGRO in Table 1-2. With the LAT and GBM, GLAST will be a flexible observatory for investigating the great range of astrophysical phenomena best studied in high-energy gamma rays. NASA plans to launch GLAST in late 2005.

  19. High-fidelity cryothermal test of a subscale large space telescope

    NASA Astrophysics Data System (ADS)

    DiPirro, M.; Tuttle, J.; Ollendorf, S.; Mattern, A.; Leisawitz, D.; Jackson, M.; Francis, J.; Hait, T.; Cleveland, P.; Muheim, D.; Mastropietro, A. J.

    2007-09-01

    To take advantage of the unique environment of space and optimize infrared observations for faint sources, space telescopes must be cooled to low temperatures. The new paradigm in cooling large space telescopes is to use a combination of passive radiative cooling and mechanical cryocoolers. The passive system must shield the telescope from the Sun, Earth, and the warm spacecraft components while providing radiative cooling to deep space. This shield system is larger than the telescope itself, and must attenuate the incoming energy by over one million to limit heat input to the telescope. Testing of such a system on the ground is a daunting task due to the size of the thermal/vacuum chamber required and the degree of thermal isolation necessary between the room temperature and cryogenic parts of the shield. These problems have been attacked in two ways: by designing a subscale version of a larger sunshield and by carefully closing out radiation sneak paths. The 18% scale (the largest diameter shield was 1.5 m) version of the SPIRIT Origins Probe telescope shield was tested in a low cost helium shroud within a 3.1 m diameter x 4.6 m long LN II shrouded vacuum chamber. Thermal straps connected from three shield stages to the liquid helium cooled shroud were instrumented with heaters and thermometers to simulate mechanical cryocooler stages at 6 K, 18-20 K, and 45-51 K. Performance data showed that less than 10 microwatts of radiative heat leaked from the warm to cold sides of the shields during the test. The excellent agreement between the data and the thermal models is discussed along with shroud construction techniques.

  20. Full Speed Ahead for Eso's Very Large Telescope First Enclosure on its way to PARANAL!

    NASA Astrophysics Data System (ADS)

    1994-09-01

    During the past months, vast progress has been made in the construction of ESO's 16-metre equivalent Very Large Telescope (VLT). This major scientific and technological project aims at installing the world's largest optical telescope in the form of four interconnected telescopes with 8.2-metre mirrors on the Paranal mountain in the Chilean Atacama desert. It continues to be on schedule as it heads towards its completion, just after the year 2000. An important milestone will be reached in early October 1994 when the first large shipment containing heavy steel parts of the enclosure for VLT Unit Telescope no. 1 leaves the Italian port of Genova [1]. Meanwhile the construction work on the Paranal site is also progressing very well. It is now expected that, as planned, the first enclosure will be ready in May 1995 to receive the first 8.2-metre telescope. This Press Release is accompanied by four colour pictures that illustrate some of the most recent developments. CONSTRUCTION PROGRESS IN EUROPE Considerable progress has been made by ESO's industrial partners in Europe, and the VLT Project has now entered into a new and dynamic phase of construction. The first 8.2-metre mirror is currently in the middle of a two-year polishing process at the REOSC company near Paris, and the first interferometric tests have shown that this very delicate operation is progressing well. The enormous mirror surface, with a total area of more than 50 m^2, is slowly but steadily approaching the desired shape which must be achieved within a few hundred-thousandths of one millimetre over the entire surface. Mirror blank no. 2 is now ready at the Schott factory in Mainz (Germany) and will be delivered by barge transport to REOSC in October 1994. Blank no. 3 has successfully completed the critical ceramization phase and blank no. 4 will soon receive the same treatment. The circular steel track, 18 metres in diameter, that will support Telescope no. 1 has now been successfully machined at the

  1. Towards a Network of Small Aperture Telescopes with Adaptive Optics Correction Capability

    NASA Astrophysics Data System (ADS)

    Cegarra Polo, M.; Lambert, A.

    2016-09-01

    A low cost and compact Adaptive Optics (AO) system for a small aperture telescope (Meade LX200ACF 16") has been developed at UNSW Canberra, where its performance is currently being evaluated. It is based on COTS components, with the exception of a real time control loop implemented in a Field Programmable Gate Array (FPGA), populated in a small form factor board which also includes the wavefront image sensor. A Graphical User Interface (GUI) running in an external computer connected to the FPGA imaging board provides the operator with control of different parameters of the AO system; results registration; and log of gradients, Zernike coefficients and deformable mirror voltages for later troubleshooting. The U.S. Air Force Academy Falcon Telescope Network (USAFA FTN) is an international network of moderate aperture telescopes (20 inches) that provides raw imagery to FTN partners [1]. The FTN supports general purpose use, including astronomy, satellite imaging and STEM (Science, Technology, Engineering and Mathematics) support. Currently 5 nodes are in operation, operated on-site or remotely, and more are to be commissioned over the next few years. One of the network nodes is located at UNSW Canberra (Australia), where the ground-based space surveillance team is currently using it for research in different areas of Space Situational Awareness (SSA). Some current and future SSA goals include geostationary satellite characterization through imaging modalities like polarimetry and real time image processing of Low Earth Orbit (LEO) objects. The fact that all FTN nodes have the same configuration facilitates the collaborative work between international teams of different nodes, so improvements and lessons learned at one site can be extended to the rest of nodes. With respect to this, preliminary studies of the imagery improvement that would be achieved with the AO system developed at UNSW, installed on a second 16 inch Meade LX200ACF telescope and compared to the

  2. MegaMIR: The Megapixel Mid-Infrared Instrument for the Large Binocular Telescope Interferometer

    NASA Technical Reports Server (NTRS)

    Mainzer, Amanda K.; Young, Erick; Hong, John; Werner, Mike; Hinz, Phil; Gorjan, Varoujan; Ressler, Michael E.

    2006-01-01

    The Megapixel Mid-infrared Instrument (MegaMIR) is a proposed Fizeau-mode camera for the Large Binocular Telescope operating at wavelengths between 5 and 28 micrometers. The camera will be used in conjunction with the Large Binocular Telescope Interferometer (LBTI), a cryogenic optical system that combines the beams from twin 8.4-m telescopes in a phase coherent manner. Unlike other interferometric systems, the co-mounted telescopes on the LBT satisfy the sine condition, providing diffraction-limited resolution over the 40" field of view of the camera. With a 22.8-m baseline, MegaMIR will yield 0.1" angular resolution, making it the highest resolution wide field imager in the thermal infrared for at least the next decade. MegaMIR will utilize a newly developed 1024 x 1024 pixel Si:As detector array that has been optimized for use at high backgrounds. This new detector is a derivative of the Wide-field Infrared Survey Explorer (WISE) low-background detector. The combination of high angular resolution and wide field imaging will be a unique scientific capability for astronomy. Key benefits will be realized in planetary science, galactic, and extra-galactic astronomy. High angular resolution is essential to disentangle highly complex sources, particularly in star formation regions and external galaxies, and MegaMIR provides this performance over a full field of view. Because of the great impact being made by space observatories like the Spitzer Space Telescope, the number of available targets for study has greatly increased in recent years, and MegaMIR will allow efficient follow up science.

  3. Adaptive Control Techniques for Large Space Structures

    DTIC Science & Technology

    1987-12-23

    2500 Mizssion. CoV~ege Boulevard Sar-ta Clara, Califorr-Iia 950541-1215 P--epared for: AFOSR, O irectcorate of Aerospace Sciences Bolling Air Force...formulated in late 1982 in re- sponse to the increasing concern that performance robustness of Air Force LSS type system would be inadequate to meet...Reducing the effects of on-board disturbance rejection) is particularly important for planned Air Force missions. For these cases, adaptive control

  4. The anti-coincidence detector for the GLAST large area telescope

    NASA Astrophysics Data System (ADS)

    Moiseev, A. A.; Hartman, R. C.; Ormes, J. F.; Thompson, D. J.; Amato, M. J.; Johnson, T. E.; Segal, K. N.; Sheppard, D. A.

    2007-06-01

    This paper describes the design, fabrication and testing of the Anti-Coincidence Detector (ACD) for the Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT). The ACD is LATs first-level defense against the charged cosmic ray background that outnumbers the gamma rays by 3 5 orders of magnitude. The ACD covers the top and four sides of the LAT tracking detector, requiring a total active area of ˜8.3 m2. The ACD detector utilizes plastic scintillator tiles with wavelength shifting fiber readout. In order to suppress self-veto by shower particles at high gamma-ray energies, the ACD is segmented into 89 tiles of different sizes. The overall ACD efficiency for detection of singly charged relativistic particles entering the tracking detector from the top or sides of the LAT exceeds the required 0.9997.

  5. A project for an infrared synoptic survey from Antarctica with the Polar Large Telescope (PLT)

    NASA Astrophysics Data System (ADS)

    Epchtein, N.; Abe, L.; Ansorge, W.; Langlois, M.; Vauglin, I.; Argentini, S.; Esau, I.; David, C.; Bryson, I.; Dalton, G.; Ashley, M. C. B.; Lawrence, J. S.

    2011-12-01

    The Polar Large Telescope (PLT) aims at performing a new generation of astronomical Infrared Synoptic Survey from Antarctica (ISSA). It would carry out for the first time large scale periodic imaging surveys at ˜ 0.3 arcsec angular resolution in the short thermal infrared (2-5 micron) range benefiting from the extremely dry, cold, and stable polar atmosphere. The PLT consists of a 2.5 m class telescope equipped with a 250-Mpixel infrared camera. The survey would produce diffraction limited images at 2 micron covering a total of ˜ 5000 square degrees, explore the time domain from seconds to years down to mab =25.5 in Kd, generate alerts of transients and react quickly to alerts from other ground based or space borne facilities.

  6. The Anti-Coincidence Detector for the GLAST Large Area Telescope

    SciTech Connect

    Moiseev, A.A.; Hartman, R.C.; Ormes, J.F.; Thompson, D.J.; Amato, M.J.; Johnson, T.E.; Segal, K.N.; Sheppard, D.A.

    2007-03-23

    This paper describes the design, fabrication and testing of the Anti-Coincidence Detector (ACD) for the Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT). The ACD is LAT's first-level defense against the charged cosmic ray background that outnumbers the gamma rays by 3-5 orders of magnitude. The ACD covers the top and 4 sides of the LAT tracking detector, requiring a total active area of {approx}8.3 square meters. The ACD detector utilizes plastic scintillator tiles with wave-length shifting fiber readout. In order to suppress self-veto by shower particles at high gamma-ray energies, the ACD is segmented into 89 tiles of different sizes. The overall ACD efficiency for detection of singly charged relativistic particles entering the tracking detector from the top or sides of the LAT exceeds the required 0.9997.

  7. Large Binocular Telescope Observations of Europa Occulting Io's Volcanoes at 4.8 μm

    NASA Astrophysics Data System (ADS)

    Skrutskie, Michael F.; Conrad, Albert; Resnick, Aaron; Leisenring, Jarron; Hinz, Phil; de Pater, Imke; de Kleer, Katherine; Spencer, John; Skemer, Andrew; Woodward, Charles E.; Davies, Ashley Gerard; Defrére, Denis

    2015-11-01

    On 8 March 2015 Europa passed nearly centrally in front of Io. The Large Binocular Telescope observed this event in dual-aperture AO-corrected Fizeau interferometric imaging mode using the mid-infrared imager LMIRcam operating behind the Large Binocular Telescope Interferometer (LBTI) at a broadband wavelength of 4.8 μm (M-band). Occultation light curves generated from frames recorded every 123 milliseconds show that both Loki and Pele/Pillan were well resolved. Europa's center shifted by 2 kilometers relative to Io from frame-to-frame. The derived light curve for Loki is consistent with the double-lobed structure reported by Conrad et al. (2015) using direct interferometric imaging with LBTI.

  8. First light for the sodium laser guide star adaptive optics system on the Lijiang 1.8m telescope

    NASA Astrophysics Data System (ADS)

    Wei, Kai; Li, Min; Chen, Shan-Qiu; Bo, Yong; Chen, Feng; Zuo, Jun-Wei; Bian, Qi; Yao, Ji; Zhou, Lu-Chun; Wei, Lin; Chen, Dong-Hong; Gao, Yang; Jin, Kai; Dai, Xiao-Lin; Fu, Han-Chu; Xu, Chang; Wang, Zhi-Chao; Xue, Xiang-Hui; Chen, Xue-Wu; Qian, Xian-Mei; Zhou, Yu; Xian, Hao; Peng, Qin-Jun; Rao, Chang-Hui; Xu, Zu-Yan; Zhang, Yu-Dong

    2016-12-01

    A first generation sodium Laser Guide Star Adaptive Optics System (LGS-AOS) was developed and integrated into the Lijiang 1.8m telescope in 2013. The LGS-AOS has three sub-systems: (1) a 20 W long pulsed sodium laser, (2) a 300-millimeter-diameter laser launch telescope, and (3) a 37-element compact adaptive optics system. On 2014 January 25, we obtained high resolution images of an mV 8.18 star, HIP 43963, during the first light of the LGS-AOS. In this paper, the sodium laser, the laser launch telescope, the compact adaptive optics system and the first light results will be presented.

  9. Computational performance comparison of wavefront reconstruction algorithms for the European Extremely Large Telescope on multi-CPU architecture.

    PubMed

    Feng, Lu; Fedrigo, Enrico; Béchet, Clémentine; Brunner, Elisabeth; Pirani, Werther

    2012-06-01

    The European Southern Observatory (ESO) is studying the next generation giant telescope, called the European Extremely Large Telescope (E-ELT). With a 42 m diameter primary mirror, it is a significant step from currently existing telescopes. Therefore, the E-ELT with its instruments poses new challenges in terms of cost and computational complexity for the control system, including its adaptive optics (AO). Since the conventional matrix-vector multiplication (MVM) method successfully used so far for AO wavefront reconstruction cannot be efficiently scaled to the size of the AO systems on the E-ELT, faster algorithms are needed. Among those recently developed wavefront reconstruction algorithms, three are studied in this paper from the point of view of design, implementation, and absolute speed on three multicore multi-CPU platforms. We focus on a single-conjugate AO system for the E-ELT. The algorithms are the MVM, the Fourier transform reconstructor (FTR), and the fractal iterative method (FRiM). This study enhances the scaling of these algorithms with an increasing number of CPUs involved in the computation. We discuss implementation strategies, depending on various CPU architecture constraints, and we present the first quantitative execution times so far at the E-ELT scale. MVM suffers from a large computational burden, making the current computing platform undersized to reach timings short enough for AO wavefront reconstruction. In our study, the FTR provides currently the fastest reconstruction. FRiM is a recently developed algorithm, and several strategies are investigated and presented here in order to implement it for real-time AO wavefront reconstruction, and to optimize its execution time. The difficulty to parallelize the algorithm in such architecture is enhanced. We also show that FRiM can provide interesting scalability using a sparse matrix approach.

  10. Operational metrics for the ESO Very Large Telescope: lessons learned and future steps

    NASA Astrophysics Data System (ADS)

    Primas, F.; Marteau, S.; Tacconi-Garman, L. E.; Mainieri, V.; Mysore, S.; Rejkuba, M.; Hilker, M.; Patat, F.; Sterzik, M.; Kaufer, A.; Mieske, S.

    2016-07-01

    When ESO's Very Large Telescope opened its first dome in April 1999 it was the first ground-based facility to offer to the scientific community access to an 8-10m class telescope with both classical and queue observing. The latter was considered to be the most promising way to ensure the observing flexibility necessary to execute the most demanding scientific programmes under the required, usually very well defined, conditions. Since then new instruments have become operational and 1st generation ones replaced, filling the 12 VLT foci and feeding the VLT Interferometer and its four Auxiliary Telescopes. Operating efficiently such a broad range of instruments installed and available every night of the year on four 8-metre telescopes offers many challenges. Although it may appear that little has changed since 1999, the underlying VLT operational model has evolved in order to accommodate different requirements from the user community and features of new instruments. Did it fulfil its original goal and, if so, how well? How did it evolve? What are the lessons learned after more than 15 years of operations? A careful analysis and monitoring of statistics and trends in Phase 1 and Phase 2 has been deployed under the DOME (Dashboard for Operational Metrics at ESO) project. The main goal of DOME is to provide robust metrics that can be followed with time in a user-friendly manner. Here, we summarize the main findings on the handling of service mode observations and present the most recent developments.

  11. Foundation, excavation and radiation shielding concepts for a 16-m large lunar telescope

    NASA Astrophysics Data System (ADS)

    Chua, Koon M.; Johnson, Stewart W.

    1991-09-01

    NASA is considering a 16-m diameter optical telescope on the moon as a part of the Space Exploration Initiative. Fundamental concepts of engineering activities on the moon and how they can be applied to the establishment of a 16-m large lunar telescope (LLT) are discussed. These fundamental concepts include the engineering response of lunar soils and how they affect construction activities, namely, drilling, blasting, ripping, digging and compaction. A mirror support structure and foundation design concept is proposed. The foundation considered is a multiple contact points spud-can type footing. It does not appear that a deep foundation or the presence of bedrock is required to achieve the telescope foundation stiffness. The LLT system will include a regolith covered housing, the size of a small room, which will contain sensitive electronic equipment including charge coupled devices which need protection from cosmic radiation effects. A brief discussion is made on radiation, radiation transport and radiation effects on electronics and on humans. Radiation protection techniques and the different emplacement schemes for the LLT instrument housing for radiation protection are suggested. A structural concept of an early lunar based telescope is also presented.

  12. Double stage Lyot coronagraph with the apodized reticulated stop for the Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Yaitskova, Natalia

    2005-08-01

    One of the science drivers for the Extremely Large Telescope (ELT) is imaging and spectroscopy of exo-solar planets located as close as 20mas to their parent star [1]. The application requires a well thought-out design of the high contrast imaging instrumentation. Several working coronagraphic concepts have already been developed for the monolithic telescope with the diameter up to 8 meter. Nevertheless the conclusions made about the performance of these systems cannot be applied directly to the telescope of the diameter 30-100m. The existing schemes are needed to be reconsidered taking into account the specific characteristics of a segmented surface. We start this work with the classical system - Lyot coronagraph. We show that while the increase in telescope diameter is an advantage for the high contrast range science, the segmentation sets a limit on the performance of the coronagraph. Diffraction from intersegment gaps sets a floor to the achievable extinction of the starlight. Masking out the bright segment gaps in the Lyot plane although helps increasing the contrast, does not solve completely the problem: the high spatial frequency component of the diffractive light remains. We suggest using the Lyot stop which acts on the light within gaps in order to produce the uniform illumination in the Lyot plane. We show that for the diffraction limit regime and a perfect phasing this type of coronagraph achieves a sufficient star light extinction.

  13. Foundation, excavation and radiation shielding concepts for a 16-m large lunar telescope

    NASA Technical Reports Server (NTRS)

    Chua, Koon M.; Johnson, Stewart W.

    1991-01-01

    NASA is considering a 16-m diameter optical telescope on the moon as a part of the Space Exploration Initiative. Fundamental concepts of engineering activities on the moon and how they can be applied to the establishment of a 16-m large lunar telescope (LLT) are discussed. These fundamental concepts include the engineering response of lunar soils and how they affect construction activities, namely, drilling, blasting, ripping, digging and compaction. A mirror support structure and foundation design concept is proposed. The foundation considered is a multiple contact points spud-can type footing. It does not appear that a deep foundation or the presence of bedrock is required to achieve the telescope foundation stiffness. The LLT system will include a regolith covered housing, the size of a small room, which will contain sensitive electronic equipment including charge coupled devices which need protection from cosmic radiation effects. A brief discussion is made on radiation, radiation transport and radiation effects on electronics and on humans. Radiation protection techniques and the different emplacement schemes for the LLT instrument housing for radiation protection are suggested. A structural concept of an early lunar based telescope is also presented.

  14. Propellantless precision formation flying with photonic laser thrusters for large space telescopes

    NASA Astrophysics Data System (ADS)

    Bae, Young K.

    2009-08-01

    One economically and technologically feasible bedrock structure for constructing large (diameter > 10 m) space telescopes is a segmented or sparse aperture system with subcomponents in precision formation flight. For UV/Visible/IR systems, initial targeting and targeting new objects to establish initial fringes requires the positioning precision to nm - μm accuracy, thus the control system should be capable of the required precision positioning and attitude controls without producing contaminations from thruster exhaust plumes. A nanometer accuracy contaminationfree formation architecture, Photon Tether Formation Flight (PTFF), based on Photonic Laser Thrusters (PLTs) and tethers has been proposed to exploit a force equilibrium formed by PLT thrust and tether tension for forming precision persistent 3-D formation structures ideal for the large UV/Visible/IR space telescopes. The range of the PLT force can theoretically extend over several kms. Under previous NASA sponsorship, we have successfully demonstrated a proofof- concept PLT. In addition, the demonstrations of required laser components, optics and tracking technologies developed under military laser applications now support that implementation of PLTs for large space telescopes is one step closer to reality.

  15. 2-micron Adaptive Optics Images of Titan from the W.M. Keck Telescope

    NASA Astrophysics Data System (ADS)

    Gibbard, S. G.; Macintosh, B. A.; Max, C. E.; de Pater, I.; Roe, H. G.; Marchis, F.

    2001-12-01

    Saturn's largest moon Titan is the only satellite in the solar system with a substantial atmosphere, which consists mainly of nitrogen and a few percent methane. Photolysis of methane creates a hydrocarbon haze in Titan's atmosphere that is opaque to visible light. However, in the infrared there are `windows' between methane absorption bands in which the surface of Titan can be imaged. We have observed Titan over the period of 1999-2001 using the adaptive optics system on the 10-meter W.M. Keck Telescope. Using adaptive optics allows us to observe Titan with a resolution of 0.04 arcseconds, or approximately 20 resolution elements across the satellite's disk. We will report on adaptive optics images of Titan taken in 1999-2001 at K band (1.95-2.29 microns). The images are enhanced by application of the MISTRAL iterative image deconvolution routine. Using this data combined with atmospheric modeling, we are able to determine Titan's surface albedo at this wavelength and properties of its hydrocarbon haze layer. This research was supported in part by the STC Program of the National Science Foundation under Agreement No. AST-9876783, and in part under the auspices of the US Department of Energy at Lawrence Livermore National Laboratory, Univ. of Calif. under contract No. W-7405-Eng-48.

  16. A Research on the Primary Mirror Manipulator of Large Segmented-mirror Telescope

    NASA Astrophysics Data System (ADS)

    Zuo, H.

    2012-09-01

    Since Galileo firstly used the telescope to observe the sky 400 years ago, the aperture of the telescope has become larger and larger to observe the deeper universe, and the segmented-mirror telescope is becoming more and more popular with increasing aperture. In the early 21st century, a series of segmented-mirror telescopes have been constructed including the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) of China. LAMOST is a meridian reflecting Schmidt telescope, and the dimension of the primary mirror is about 6.7 m× 6 m, which is composed of 37 hexagonal sub-mirrors. However, a problem about the mirror installation appears with the increasing aperture. If there are hundreds of sub-mirrors in the telescope, it is a challenging job to mount and dismount them to the truss. This problem is discussed in this paper and a manipulator for the primary mirror of LAMOST is designed to perform the mount and dismount work. In chapter 1, all the segmented-mirror telescopes in the world are introduced and how the sub-mirrors of these telescopes are installed has been investigated. After comparing with the serial and the parallel robot, a serial robot manipulator proposal, which has several redundant degrees of freedom (DOFs), has been chosen from a series of design proposals. In chapter 2, the theoretical analysis has been carried out on the basis of the design proposal, which includes the forward kinematics and the inverse kinematics. Firstly the D-H coordinate is built according to the structure of the manipulator, so it is possible to obtain the end-effector position and orientation from the individual joint motion thanks to the forward kinematics. Because of the redundant DOFs of the manipulator, the inverse kinematics solution can be a very trick task, and the result may not be only, therefore a kind of simulation is carried out to get the numerical solution using ADAMS (Automatic Dynamic Analysis of Mechanical System). In the dynamics analysis the

  17. Subaru Telescope adaptive optics observations of gravitationally lensed quasars in the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Rusu, Cristian E.; Oguri, Masamune; Minowa, Yosuke; Iye, Masanori; Inada, Naohisa; Oya, Shin; Kayo, Issha; Hayano, Yutaka; Hattori, Masayuki; Saito, Yoshihiko; Ito, Meguru; Pyo, Tae-Soo; Terada, Hiroshi; Takami, Hideki; Watanabe, Makoto

    2016-05-01

    We present the results of an imaging observation campaign conducted with the Subaru Telescope adaptive optics system (IRCS+AO188) on 28 gravitationally lensed quasars and candidates (23 doubles, 1 quad, 1 possible triple, and 3 candidates) from the SDSS Quasar Lens Search. We develop a novel modelling technique that fits analytical and hybrid point spread functions (PSFs), while simultaneously measuring the relative astrometry, photometry, as well as the lens galaxy morphology. We account for systematics by simulating the observed systems using separately observed PSF stars. The measured relative astrometry is comparable with that typically achieved with the Hubble Space Telescope, even after marginalizing over the PSF uncertainty. We model for the first time the quasar host galaxies in five systems, without a priori knowledge of the PSF, and show that their luminosities follow the known correlation with the mass of the supermassive black hole. For each system, we obtain mass models far more accurate than those previously published from low-resolution data, and we show that in our sample of lensing galaxies the observed light profile is more elliptical than the mass, for ellipticity ≳0.25. We also identify eight doubles for which the sources of external and internal shear are more reliably separated, and should therefore be prioritized in monitoring campaigns aimed at measuring time delays in order to infer the Hubble constant.

  18. Prospects for Measuring Supermassive Black Hole Masses with Future Extremely Large Telescopes

    NASA Astrophysics Data System (ADS)

    Do, Tuan; Wright, S. A.; Barton, E. J.; Barth, A. J.; Simard, L.; Larkin, J. E.; Moore, A.

    2013-01-01

    The next generation of giant-segmented mirror telescopes (> 20 m) will enable us to observe galactic nuclei at much higher angular resolution and sensitivity than ever before. These capabilities will introduce a revolutionary shift in our understanding of the origin and evolution of supermassive black holes by enabling more precise black hole mass measurements in a mass range that is unreachable today. We present simulations and predictions of the observations of nuclei that will be made with the Thirty Meter Telescope (TMT) and the adaptive optics assisted integral-field spectrograph IRIS. These simulations, for the first time, use realistic values for the sky, telescope, adaptive optics system, and instrument, to determine the expected signal-to-noise of a range of possible targets spanning intermediate mass black holes of ~10^4 M⊙ to the most massive black holes known today of >10^10 M⊙. We find that future integral-field spectrographs will be able to observe Milky Way-mass black holes out the distance of the Virgo cluster, and will allow us to observe many more brightest-cluster galaxies where the most massive black holes are thought to reside. We also evaluate how well the kinematic moments of the velocity distributions can be constrained at different spectral resolutions and plate scales. We find that a spectral resolution of ~8000 will be necessary to measure the masses of IMBHs. We find by using the SDSS DR7 catalog of galaxies that over 4000 massive black holes will be observable at distances between 0.005 < z < 0.3 with the estimated sensitivity and angular resolution of TMT. These observations will provide the most accurate dynamical mass measurements of black holes to enable the study of their demography, address the origin of the M_bh-σ and M_bh - L relationships, and the origins and evolution of black holes through cosmic time.

  19. ATLAST-9.2: A Deployable Large Aperture UVOIR Space Telescope

    NASA Technical Reports Server (NTRS)

    Oegerle, William R.; Feinberg, L.; Purves, L.; Hyde, T.; Thronson, H.; Townsend, J.; Postman, M.; Bolcar, M.; Budinoff, J.; Dean, B.; Clampin, N.; Ebbets, D.; Gong, Q.; Gull, T.; Howard, J.; Jones, A.; Lyon, R.; Pasquale, B.; Perrygo, C.; Smith, S.; Thompson, P.; Woodgate, B.

    2010-01-01

    We present the results of a study of a deployable version of the Advanced Technology Large Aperture Space Telescope (ATLAST) that could be launched on an Evolved Expendable Launch Vehicle (EELV). ATLAST is a concept for a next-generation UVOIR observatory to follow HST and JWST. The observatory retains significant heritage from JWST, thereby taking advantage of technologies and engineering already developed for that mission. At the same time, we have identified several design changes to the JWST architecture, some of which are required due to the demanding wavefront error requirements at visible wavelengths. The optical telescope assembly has a segmented 9.2-meter aperture and consists of 36 hexagonal glass mirrors, each of which is I.3l5m in size (flat-to-flat). The telescope can be folded to fit in the 6.5m fairing on the planned upgrade to the Delta-IV heavy launch vehicle. Near-real time wavefront sensing and control is performed on-board the telescope using stars in the field of view to deliver diffraction limited imaging performance at 500nm wavelength. The optical design of the telescope provides an 8x20 arcmin FOV in which 4-5 instruments can be accommodated, plus fine guidance and wavefront sensors. Unlike JWST, the OTA sits at the end of a multi-gimbaled arm, allowing pitch and roll motion, and is isolated from the sunshield and spacecraft bus by an active isolation system. Our design permits servicing in order to extend the life of the observatory.

  20. Lick Observatory's Shane telescope adaptive optics system (ShaneAO): research directions and progress

    NASA Astrophysics Data System (ADS)

    Gavel, Donald T.; Kupke, Renate; Rudy, Alexander R.; Srinath, Srikar; Dillon, Daren; Poyneer, Lisa A.

    2016-07-01

    We present a review of the ongoing research activity surrounding the adaptive optics system at the Shane telescope (ShaneAO) particularly the R&D efforts on the technology and algorithms for that will advance AO into wider application for astronomy. We are pursuing the AO challenges for whole sky coverage diffraction-limited correction down to visible science wavelengths. This demands high-order wavefront correction and bright artificial laser beacons. We present recent advancements in the development of MEMS based AO correction, woofer-tweeter architecture, wind-predictive wavefront control algorithms, atmospheric characterization, and a pulsed fiber amplifier guide star laser tuned for optical pumping of the sodium layer. We present the latest on-sky results from the new AO system and present status and experimental plans for the optical pumping guide star laser.

  1. Adaptive system for solar telescopes operating in the strongly turbulent atmosphere

    NASA Astrophysics Data System (ADS)

    Antoshkin, L. V.; Botugina, N. N.; Bolbasova, L. A.; Demidov, M. L.; Grigoriev, V. M.; Emaleev, O. N.; Konyaev, P. A.; Kopylov, E. A.; Kovadlo, P. G.; Kudryashov, A. V.; Lavrinov, V. V.; Lavrinova, L. N.; Lukin, V. P.; Shikhovtcev, A. Yu.; Trifonov, V. D.

    2016-07-01

    In this article, we describe the development of the newest adaptive optics system for the Big Solar Vacuum Telescope of the Baikal Astrophysical Observatory. This system is a result of collaboration between VE Zuev Institute of Atmospheric Optics SB RAS, Tomsk, and Institute of Solar-Terrestrial Physics SB RAS, Irkutsk. The system includes two active mirrors for the correction: domestic tip-tilt and bimorph deformable (Active Optics NightN Ltd.), and separate wavefront sensors (WFS). A correlation S-H wave-front sensor is based on a Allies Prosilica GX-1050 GigE camera with speed of 309 Hz and frame size of 1248x1248 pixels. A personal computer is used for bimorph deformable mirror image processing. The mirror was successfully used during the 2010-2014 observing seasons. The system developed is capable of correcting up to 35 modes, thus providing diffraction limited images at visible wavelengths.

  2. Fabrication of large-aperture, high efficiency, Fresnel diffractive membrane optic for space telescope

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Li, Mengjuan; Yin, Ganghua; Jiao, Jianchao; Liu, Zhengkun; Xu, Xiangdong; Fu, Shaojun

    2016-10-01

    Diffractive optical system can be a favorable choice for large-aperture space telescope to reduce the mass and size of image system. To meet the demand of large-aperture, high efficiency, lightweight diffractive optic for high resolution remote sensing, a 200 mm diameter, 20 μmthick, 4-level diffractive membrane fabricated is shown to have over 62% diffraction efficiency into the +1 order, with 0.051 efficiency RMS. Over 66% diffraction efficiency is achieved for a 100 mm aperture membrane, with 0.023 efficiency RMS. The membrane thickness uniformity control is discussed and 8 nm wave front error RMS is achieved in 100 mm diameter.

  3. Fermi Large Area Telescope Observations of the Dark Accelerator HESS J1745-303

    NASA Astrophysics Data System (ADS)

    Yeung, Paul

    2016-12-01

    Reviewing the two MeV-GeV investigations in the field of the HESS J1745-303 performed using Fermi Large Area Telescope data, we confirmed that the emission peak comfortably coincides with ‘Region A’ in the TeV regime, which is the brightest part of this feature. The MeV–TeV spectrum can be precisely described by a single power-law. Also, recent investigation has shown that the MeV-GeV feature is elongated from ‘Region A’ toward the north-west, which is similar to the case of large- scale atomic/molecular gas distribution.

  4. Toward large-area sub-arcsecond x-ray telescopes II

    NASA Astrophysics Data System (ADS)

    O'Dell, Stephen L.; Allured, Ryan; Ames, Andrew O.; Biskach, Michael P.; Broadway, David M.; Bruni, Ricardo J.; Burrows, David N.; Cao, Jian; Chalifoux, Brandon D.; Chan, Kai-Wing; Chung, Yip-Wah; Cotroneo, Vincenzo; Elsner, Ronald F.; Gaskin, Jessica A.; Gubarev, Mikhail V.; Heilmann, Ralf K.; Hertz, Edward; Jackson, Thomas N.; Kilaru, Kiranmayee; Kolodziejczak, Jeffrey J.; McClelland, Ryan S.; Ramsey, Brian D.; Reid, Paul B.; Riveros, Raul E.; Roche, Jacqueline M.; Romaine, Suzanne E.; Saha, Timo T.; Schattenburg, Mark L.; Schwartz, Daniel A.; Schwartz, Eric D.; Solly, Peter M.; Trolier-McKinstry, Susan; Ulmer, Melville P.; Vikhlinin, Alexey; Wallace, Margeaux L.; Wang, Xiaoli; Windt, David L.; Yao, Youwei; Ye, Shi; Zhang, William W.; Zuo, Heng

    2016-09-01

    In order to advance significantly scientific objectives, future x-ray astronomy missions will likely call for x-ray telescopes with large aperture areas (≍ 3 m2) and fine angular resolution (≍ 12). Achieving such performance is programmatically and technologically challenging due to the mass and envelope constraints of space-borne telescopes and to the need for densely nested grazing-incidence optics. Such an x-ray telescope will require precision fabrication, alignment, mounting, and assembly of large areas (≍ 600 m2) of lightweight (≍ 2 kg/m2 areal density) high-quality mirrors, at an acceptable cost (≍ 1 M$/m2 of mirror surface area). This paper reviews relevant programmatic and technological issues, as well as possible approaches for addressing these issues-including direct fabrication of monocrystalline silicon mirrors, active (in-space adjustable) figure correction of replicated mirrors, static post-fabrication correction using ion implantation, differential erosion or deposition, and coating-stress manipulation of thin substrates.

  5. Toward Large-Area Sub-Arcsecond X-Ray Telescopes II

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Allured, Ryan; Ames, Andrew O.; Biskach, Michael P.; Broadway David M.; Bruni, Ricardo J.; Burrows, David; Cao, Jian; Chalifoux, Brandon D.; Chan, Kai-Wing; Chung, Yip-Wah; Cotroneo, Vincenzo; Elsner, Ronald F.; Gaskin, Jessica A.; Gubarev, Mikhail V.; Heilmann, Ralf K.; Hertz, Edward; Jackson, Thomas N.; Kilaru, Kiranmayee; Kolodziejczak, Jeffery J.; McClelland, Ryan S.; Ramsey, Brian D.; Reid, Paul B.; Riveros, Raul E.; Roche, Jacqueline M.; Romaine, Suzanne E.; Saha, Timo T.; Schattenburg, Mark L.; Schwartz, Daniel A.; Schwartz, Eric D.; Solly, Peter M.; Trolier-McKinstry, Susan E.; Ulmer, Mellville P.; Vikhlilin, Alexey; Wallace, Margeaux L.; Zhang, William W.

    2016-01-01

    In order to advance significantly scientific objectives, future x-ray astronomy missions will likely call for x-ray telescopes with large aperture areas (approx. = 3 sq m) and fine angular resolution (approx. = 1"). Achieving such performance is programmatically and technologically challenging due to the mass and envelope constraints of space-borne telescopes and to the need for densely nested grazing-incidence optics. Such an x-ray telescope will require precision fabrication, alignment, mounting, and assembly of large areas (approx. = 600 sq m) of lightweight (approx. = 2 kg/sq m areal density) high-quality mirrors, at an acceptable cost (approx. = 1 M$/sq m of mirror surface area). This paper reviews relevant programmatic and technological issues, as well as possible approaches for addressing these issues-including direct fabrication of monocrystalline silicon mirrors, active (in-space adjustable) figure correction of replicated mirrors, static post-fabrication correction using ion implantation, differential erosion or deposition, and coating-stress manipulation of thin substrates.

  6. Gamma Ray Large Area Space Telescope (GLAST) Balloon Flight Engineering Model: Overview

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Godfrey, G.; Williams, S. M.; Grove, J. E.; Mizuno, T.; Sadrozinski, H. F.-W.; Kamae, T.; Ampe, J.; Briber, Stuart; Dann, James; White, Nicholas E. (Technical Monitor)

    2001-01-01

    The Gamma Ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) is a pair-production high-energy (greater than 20 MeV) gamma-ray telescope being built by an international partnership of astrophysicists and particle physicists for a satellite launch in 2006, designed to study a wide variety of high-energy astrophysical phenomena. As part of the development effort, the collaboration has built a Balloon Flight Engineering Model (BFEM) for flight on a high-altitude scientific balloon. The BFEM is approximately the size of one of the 16 GLAST-LAT towers and contains all the components of the full instrument: plastic scintillator anticoincidence system (ACD), high-Z foil/Si strip pair-conversion tracker (TKR), CsI hodoscopic calorimeter (CAL), triggering and data acquisition electronics (DAQ), commanding system, power distribution, telemetry, real-time data display, and ground data processing system. The principal goal of the balloon flight was to demonstrate the performance of this instrument configuration under conditions similar to those expected in orbit. Results from a balloon flight from Palestine, Texas, on August 4, 2001, show that the BFEM successfully obtained gamma-ray data in this high-background environment.

  7. Solar Sail - Fresnel Zone Plate Lens for a Large Space Based Telescope

    SciTech Connect

    Early, J T

    2002-02-13

    A Fresnel zone plate lens made with solar sail material could be used as the primary optic for a very large aperture telescope on deep space probes propelled by solar sails. The large aperture telescope capability could enable significant science on fly-by missions to the asteroids, Pluto, Kuiper belt or the tort cloud and could also enable meaningful interstellar fly-by missions for laser propelled sails. This type of lens may also have some potential for laser communications and as a solar concentrator. The techniques for fabrication of meter size and larger Fresnel phase plate optics are under development at LLNL, and we are extending this technology to amplitude zone plates made from sail materials. Corrector optics to greatly extend the bandwidth of these Fresnel optics will be demonstrated in the future. This novel telescope concept will require new understanding of the fabrication, deployment and control of gossamer space structures. It will also require new materials technology for fabricating these optics and understanding their long term stability in a space environment.

  8. Recursive architecture for large-scale adaptive system

    NASA Astrophysics Data System (ADS)

    Hanahara, Kazuyuki; Sugiyama, Yoshihiko

    1994-09-01

    'Large scale' is one of major trends in the research and development of recent engineering, especially in the field of aerospace structural system. This term expresses the large scale of an artifact in general, however, it also implies the large number of the components which make up the artifact in usual. Considering a large scale system which is especially used in remote space or deep-sea, such a system should be adaptive as well as robust by itself, because its control as well as maintenance by human operators are not easy due to the remoteness. An approach to realizing this large scale, adaptive and robust system is to build the system as an assemblage of components which are respectively adaptive by themselves. In this case, the robustness of the system can be achieved by using a large number of such components and suitable adaptation as well as maintenance strategies. Such a system gathers many research's interest and their studies such as decentralized motion control, configurating algorithm and characteristics of structural elements are reported. In this article, a recursive architecture concept is developed and discussed towards the realization of large scale system which consists of a number of uniform adaptive components. We propose an adaptation strategy based on the architecture and its implementation by means of hierarchically connected processing units. The robustness and the restoration from degeneration of the processing unit are also discussed. Two- and three-dimensional adaptive truss structures are conceptually designed based on the recursive architecture.

  9. Studying the High Energy Gamma Ray Sky with Gamma Ray Large Area Space Telescope (GLAST)

    NASA Technical Reports Server (NTRS)

    Kamae, T.; Ohsugi, T.; Thompson, D. J.; Watanabe, K.

    1998-01-01

    Building on the success of the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory, the Gamma Ray Large Area Space Telescope (GLAST) will make a major step in the study of such subjects as blazars, gamma Ray bursts, the search for dark matter, supernova remnants, pulsars, diffuse radiation, and unidentified high energy sources. The instrument will be built on new and mature detector technologies such as silicon strip detectors, low-power low-noise LSI, and a multilevel data acquisition system. GLAST is in the research and development phase, and one full tower (of 25 total) is now being built in collaborating institutes. The prototype tower will be tested thoroughly at Stanford Linear Accelerator Center (SLAC) in the fall of 1999.

  10. Toward Large-Area Sub-Arcsecond X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    ODell, Stephen L.; Aldcroft, Thomas L.; Allured, Ryan; Atkins, Carolyn; Burrows, David N.; Cao, Jian; Chalifoux, Brandon D.; Chan, Kai-Wing; Cotroneo, Vincenzo; Elsner, Ronald F.; Graham, Michael E.; Gubarev, Mikhail V.; Heilmann, Ralf K.; Johnson-Wilke, Raegan L.; Kilaru, Kiranmayee; Kolodziejczak, Jeffery J.; Lillie, Charles F.; McMuldroch, Stuart; Ramsey, Brian D.; Reid, Paul B.; Riveros, Raul E.; Roche, Jacqueline M.; Saha, Timo T.; Weisskopf, Martin C.; Zhang, William W.

    2014-01-01

    The future of x-ray astronomy depends upon development of x-ray telescopes with larger aperture areas (approx. = 3 square meters) and fine angular resolution (approx. = 1 inch). Combined with the special requirements of nested grazing-incidence optics, the mass and envelope constraints of space-borne telescopes render such advances technologically and programmatically challenging. Achieving this goal will require precision fabrication, alignment, mounting, and assembly of large areas (approx. = 600 square meters) of lightweight (approx. = 1 kilogram/square meter areal density) high-quality mirrors at an acceptable cost (approx. = 1 million dollars/square meter of mirror surface area). This paper reviews relevant technological and programmatic issues, as well as possible approaches for addressing these issues-including active (in-space adjustable) alignment and figure correction.

  11. Advanced wide-field broad-passband refracting field correctors for large telescopes

    NASA Technical Reports Server (NTRS)

    Epps, H. W.; Angel, J. R. P.; Anderson, E.

    1984-01-01

    Design objectives, constraints, and optical data are presented for specific corrector designs under consideration for several large telescope projects. These include a preliminary 30-arcmin prime focus (f/2.0) refracting field corrector system for the University of California Ten-Meter Telescope (UC TMT); a compact 40-arcmin internal Cassegrain (f/1.75 hyperbola to f/5.0) broad-passband (3300 A to 1.0 micron) corrector suitable for imaging and multi-object spectroscopy at the UC TMT; three 60-arcmin Cassegrain correctors for 300-inch f/1.8 and f/2.0 parabolic primary mirrors suitable for a Fifteen-Meter NNTT/MMT; and a 300-inch 40-arcmin external Cassegrain (f/1.0 parabola to f/4.0) broad-passband (3300 A to 1.0 micron) corrector with ADC.

  12. A population of gamma-ray millisecond pulsars seen with the Fermi Large Area Telescope.

    PubMed

    Abdo, A A; Ackermann, M; Ajello, M; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Bignami, G F; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Caliandro, G A; Cameron, R A; Camilo, F; Caraveo, P A; Carlson, P; Casandjian, J M; Cecchi, C; Celik, O; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cognard, I; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Corbet, R; Cutini, S; Dermer, C D; Desvignes, G; de Angelis, A; de Luca, A; de Palma, F; Digel, S W; Dormody, M; do Couto e Silva, E; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Farnier, C; Favuzzi, C; Fegan, S J; Focke, W B; Frailis, M; Freire, P C C; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M H; Grove, J E; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hobbs, G; Hughes, R E; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Johnston, S; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knödlseder, J; Kocian, M L; Kramer, M; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Manchester, R N; Marelli, M; Mazziotta, M N; McConville, W; McEnery, J E; McLaughlin, M A; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Omodei, N; Orlando, E; Ormes, J F; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piron, F; Porter, T A; Rainò, S; Rando, R; Ransom, S M; Ray, P S; Razzano, M; Rea, N; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Romani, R W; Roth, M; Ryde, F; Sadrozinski, H F W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Schalk, T L; Sgrò, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stappers, B W; Starck, J L; Striani, E; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Tanaka, T; Thayer, J B; Thayer, J G; Theureau, G; Thompson, D J; Thorsett, S E; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Van Etten, A; Vasileiou, V; Venter, C; Vilchez, N; Vitale, V; Waite, A P; Wallace, E; Wang, P; Watters, K; Webb, N; Weltevrede, P; Winer, B L; Wood, K S; Ylinen, T; Ziegler, M

    2009-08-14

    Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. A second life can occur for neutron stars in binary systems. They can acquire mass and angular momentum from their companions, to be spun up to millisecond periods and begin radiating again. We searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars (MSPs) outside of globular clusters, using rotation parameters from radio telescopes. Strong gamma-ray pulsations were detected for eight MSPs. The gamma-ray pulse profiles and spectral properties resemble those of young gamma-ray pulsars. The basic emission mechanism seems to be the same for MSPs and young pulsars, with the emission originating in regions far from the neutron star surface.

  13. Fermi Large Area Telescope Observations of the Cosmic-Ray Induced

    SciTech Connect

    Abdo, A.

    2012-02-29

    We report on measurements of the cosmic-ray induced {gamma}-ray emission of Earth's atmosphere by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. The LAT has observed the Earth during its commissioning phase and with a dedicated Earth-limb following observation in September 2008. These measurements yielded {approx} 6.4 x 10{sup 6} photons with energies > 100 MeV and {approx} 250 hours total livetime for the highest quality data selection. This allows the study of the spatial and spectral distributions of these photons with unprecedented detail. The spectrum of the emission - often referred to as Earth albedo gamma-ray emission - has a power-law shape up to 500 GeV with spectral index {Lambda} = 2.79 {+-} 0.06.

  14. NASA Goddard Space Flight Center, on Behalf of the Fermi Large Area Telescope Collaboration

    NASA Technical Reports Server (NTRS)

    Thompson, David J.

    2010-01-01

    Because high-energy gamma rays can be produced by processes that also produce neutrinos, the gamma-ray survey of the sky by the Fermi (Gamma-ray Space Telescope offers a view of potential targets for neutrino observations. Gamma-ray bursts. Active Galactic Nuclei, and supernova remnants are all sites where hadronic, neutrino-producing interactions are plausible. Pulsars, pulsar wind nebulae, and binary sources are all phenomena that reveal leptonic particle acceleration through their gamma-ray emission. While important to gamma-ray astrophysics, such sources are of less interest to neutrino studies. This talk will present a broad overview of the constantly changing sky seen with the Large Area Telescope (LAT)on the Fermi spacecraft.

  15. The Balloon-borne Large Aperture Submillimetre Telescope (BLAST) and BLASTPol

    NASA Astrophysics Data System (ADS)

    Pascale, Enzo; Pascale

    2013-01-01

    Balloon observations from Antarctica have proven an effective and efficient way to address open Cosmological questions as well as problems in Galactic astronomy. The Balloon-borne Large Aperture Submillimetre Telescope (BLAST) is a sub-orbital mapping experiment which uses 270 bolometric detectors to image the sky in three wavebands centred at 250, 350 and 500 μm with a 1.8 m telescope. In the years before Herschel launched, BLAST provided data of unprecedented angular and spectral coverage in frequency bands close to the peak of dust emission in star forming regions in our Galaxy, and in galaxies at cosmological distances. More recently, BLASTPol was obtained by reconfiguring the BLAST focal plane as a submillimetric polarimeter to study the role that Galactic magnetic fields have in regulating the processes of star-formation. The first and successful BLASTPol flight from Antarctica in 2010 is followed by a second flight, currently scheduled for the end of 2012.

  16. ATLAST-9.2m: a Large-Aperture Deployable Space Telescope

    NASA Technical Reports Server (NTRS)

    Oergerle, William; Feinberg, Lee D.; Purves, Lloyd R.; Hyde, T. Tupper; Thronson, Harley A.; Townsend, Jacqueline A.; Postman, Marc; Bolear, Matthew R.; Budinoff, Jason G.; Dean, Bruce H.; Clampin, Mark C.; Ebbets, Dennis C.; Gong, Qian; Gull, Theodore R.; Howard, Joseph M.; Jones, Andrew L.; Lyon, Richard G.; Pasquale, Bert A.; Perrygo, Charles; Smith, Jeffrey S.; Thompson, Patrick L.; Woodgate, Bruce E.

    2010-01-01

    We present results of a study of a deployable version of the Advanced Technology Large-Aperture Space Telescope (ATLAST), designed to operate in a Sun-Earth L2 orbit. The primary mirror of the segmented 9.2-meter aperture has 36 hexagonal 1.315 m (flat to flat) glass mirrors. The architecture and folding of the telescope is similar to JWST, allowing it to fit into the 6.5 m fairing of a modest upgrade to the Delta-IV Heavy version of the Evolved Expendable Launch Vehicle (EELV). We discuss the overall observatory design, optical design, instruments, stray light, wavefront sensing and control, pointing and thermal control, and in-space servicing options.

  17. The On-Orbit Calibrations for the Fermi Large Area Telescope

    SciTech Connect

    Abdo, Aous A.; Ackermann, M.; Ajello, M.; Ampe, J.; Anderson, B.; Atwood, W.B.; Axelsson, M.; Bagagli, R.; Baldini, L.; Ballet, J.; Barbiellini, Guido; Bartelt, J.; Bastieri, Denis; Baughman, B.M.; Bechtol, K.; Bederede, D.; Bellardi, F.; Bellazzini, R.; Belli, F.; Berenji, B.; Bisello, D.; /more authors..

    2011-11-17

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.

  18. Wide field of view adaptive optical system for lightweight deployable telescope technologies

    NASA Astrophysics Data System (ADS)

    McComas, Brian K.; Cermak, Michael A.; Friedman, Edward J.

    2003-02-01

    A NASA research contract (NAS1-00116) was awarded to Ball Aerospace & Technologies Corp. in January 2000 to study wide field-of-view adaptive optical systems. These systems will be required on future high resolution Earth remote sensing systems that employ large, flexible, lightweight, deployed primary mirrors. The deformations from these primary mirrors will introduce aberrations into the optical system, which must be removed by corrective optics. For economic reasons, these remote sensing systems must have a large field-of-view (a few degrees). Unlike ground-based adaptive optical systems, which have a negligible field-of-view, the adaptive optics on these space-based remote sensing systems will be required to correct for the deformations in the primary mirror over the entire field-of-view. A new error function, which is an enhancement to conventional adaptive optics, for wide field-of-view optical systems will be introduced. This paper will present the goals of the NASA research project and its progress. The initial phase of this research project is a demonstration of the wide field-of-view adaptive optics theory. A breadboard has been designed and built for this purpose. The design and assembly of the breadboard will be presented, along with the final results for this phase of the research project. Finally, this paper will show the applicability of wide field-of-view adaptive optics to space-based astronomical systems.

  19. Adaptive Techniques for Large Space Apertures.

    DTIC Science & Technology

    1980-03-01

    GP Anitern, 200l de or,~,’rn, receiner/ proceso 1"’ - requires enternal !titude deter- minationr such as a star tracker Increased mechanizatio’ Sensor...control systems into one unit; namely, a fine pointing control using the gimbal rates as the control variables while maintaining constant rotor speeds...CMG mode), and a coarse control for large maneuvers using the rotor speeds as the control variables and locking the gimbals (RW mode). The simultaneous

  20. A method on error analysis for large-aperture optical telescope control system

    NASA Astrophysics Data System (ADS)

    Su, Yanrui; Wang, Qiang; Yan, Fabao; Liu, Xiang; Huang, Yongmei

    2016-10-01

    For large-aperture optical telescope, compared with the performance of azimuth in the control system, arc second-level jitters exist in elevation under different speeds' working mode, especially low-speed working mode in the process of its acquisition, tracking and pointing. The jitters are closely related to the working speed of the elevation, resulting in the reduction of accuracy and low-speed stability of the telescope. By collecting a large number of measured data to the elevation, we do analysis on jitters in the time domain, frequency domain and space domain respectively. And the relation between jitter points and the leading speed of elevation and the corresponding space angle is concluded that the jitters perform as periodic disturbance in space domain and the period of the corresponding space angle of the jitter points is 79.1″ approximately. Then we did simulation, analysis and comparison to the influence of the disturbance sources, like PWM power level output disturbance, torque (acceleration) disturbance, speed feedback disturbance and position feedback disturbance on the elevation to find that the space periodic disturbance still exist in the elevation performance. It leads us to infer that the problems maybe exist in angle measurement unit. The telescope employs a 24-bit photoelectric encoder and we can calculate the encoder grating angular resolution as 79.1016'', which is as the corresponding angle value in the whole encoder system of one period of the subdivision signal. The value is approximately equal to the space frequency of the jitters. Therefore, the working elevation of the telescope is affected by subdivision errors and the period of the subdivision error is identical to the period of encoder grating angular. Through comprehensive consideration and mathematical analysis, that DC subdivision error of subdivision error sources causes the jitters is determined, which is verified in the practical engineering. The method that analyze error

  1. Concept for a Large Space Telescope for Detailed Spectroscopy of Terrestrial exo-planets

    NASA Astrophysics Data System (ADS)

    Angel, J. R. P.; Woolf, N. J.; Burge, J. H.

    1998-12-01

    Once terrestrial planets of other stars are detected, cryogenic space telescopes of large collecting area will be needed to obtain detailed atmospheric spectra in the thermal infrared. Our concept is for an ultralightweight telescope with area approaching 1000 m(2) , made from large flat panels of stretched plastic membrane. Thin reflective material held in tension from points around a plane perimeter is fundamentally stable; its flat shape is not critically dependent on tension, and will hold even against penetration by micrometeorites. The perimeter support points would be actively controlled to maintain their co-planarity. We envisage about ten panels each about 10 m square, arranged on a rigid carbon composite truss to approximate a 100 m x 10 m mirror with 1 km focal length. A separate free-flyer at the quasi-focus would complete the telescope. Where all the beams from the target star overlap, a 10 m concave secondary would be used to form an image of the primary array at about 1/10 scale, and slightly below the plane of incoming beams. At each panel image would be a 1 m tertiary, suitably shaped so as to recollimate each individual starlight beam, or to bring all the beams to a common focus. From this point on the instrument might use the focus directly, or multi-aperture interferometric nulling techniques as described by Angel and Woolf. The unaberrated field will be large enough for exoplanet studies. The new technology goes beyond that needed for an 8 m NGST in two main ways: 1) need for thin metallized plastic of large size and uniform thickness and 2) capability to assemble or deploy in space the structure to support the panels.

  2. Adaptive Optics Observations of Titan from the W.M. Keck Telescope

    NASA Astrophysics Data System (ADS)

    Gibbard, S. G.; Macintosh, B.; Max, C. E.; Roe, H.; de Pater, I.; Young, E. F.; McKay, C. P.

    2000-10-01

    Saturn's largest moon Titan is the only satellite in the solar system with a substantial atmosphere. Photolysis of methane creates a hydrocarbon haze in Titan's atmosphere that is opaque to visible light. The new adaptive optics system on the 10-meter W.M. Keck Telescope enables us to observe Titan with a resolution of 0.04 arcseconds, or 20 resolution elements across the disk. By observing at near-infrared wavelengths that are methane band windows, we can see through Titan's hydrocarbon haze to the surface beneath. We will report on adaptive optics images of Titan taken in 1999, including broadband engineering images taken in February, August, and September, and broadband K and narrowband J and H band images taken in October. The narrowband filters have been chosen to selectively probe Titan's surface or atmosphere. Using this data combined with atmospheric modeling, we are able to determine surface Titan's surface albedo and properties of its hydrocarbon haze layer. This research was supported in part by the STC Program of the National Science Foundation under Agreement No. AST-9876783, and in part under the auspices of the US Department of Energy at Lawrence Livermore National Laboratory, Univ. of Calif. under contract No. W-7405-Eng-48.

  3. First-order design of off-axis reflective ophthalmic adaptive optics systems using afocal telescopes

    NASA Astrophysics Data System (ADS)

    Gómez-Vieyra, Armando; Dubra, Alfredo; Williams, David R.; Malacara-Hernández, Daniel

    2009-09-01

    Scanning laser ophthalmoscopes (SLOs) and optical coherence tomographs are the state-of-the-art retinal imaging instruments, and are essential for early and reliable diagnosis of eye disease. Recently, with the incorporation of adaptive optics (AO), these instruments have started to deliver near diffraction-limited performance in both humans and animal models, enabling the resolution of the retinal ganglion cell bodies, their processes, the cone photoreceptor and the retinal pigment epithelial cells mosaics. Unfortunately, these novel instruments have not delivered consistent performance across human subjects and animal models. One of the limitations of current instruments is the astigmatism in the pupil and imaging planes, which degrades image quality, by preventing the wavefront sensor from measuring aberrations with high spatial content. This astigmatism is introduced by the sequence of off-axis reflective elements, typically spherical mirrors, used for relaying pupil and imaging planes. Expressions for minimal astigmatism on the image and pupil planes in off-axis reflective afocal telescopes formed by pairs of spherical mirrors are presented. The formulas, derived from the marginal ray fans equation, are valid for small angles of incidence (<=15°), and can be used to design laser cavities, spectrographs and vision adaptive optics systems. An example related to this last application is discussed.

  4. Prospects for measuring supermassive black hole masses with future extremely large telescopes

    SciTech Connect

    Do, Tuan; Wright, Shelley A.; Barth, Aaron J.; Barton, Elizabeth J.; Simard, Luc; Larkin, James E.; Moore, Anna M.; Wang, Lianqi; Ellerbroek, Brent

    2014-04-01

    The next generation of giant-segmented mirror telescopes (>20 m) will enable us to observe galactic nuclei at much higher angular resolution and sensitivity than ever before. These capabilities will introduce a revolutionary shift in our understanding of the origin and evolution of supermassive black holes by enabling more precise black hole mass measurements in a mass range that is unreachable today. We present simulations and predictions of the observations of nuclei that will be made with the Thirty Meter Telescope (TMT) and the adaptive optics assisted integral-field spectrograph IRIS, which is capable of diffraction-limited spectroscopy from Z band (0.9 μm) to K band (2.2 μm). These simulations, for the first time, use realistic values for the sky, telescope, adaptive optics system, and instrument to determine the expected signal-to-noise ratio of a range of possible targets spanning intermediate mass black holes of ∼10{sup 4} M {sub ☉} to the most massive black holes known today of >10{sup 10} M {sub ☉}. We find that IRIS will be able to observe Milky Way mass black holes out the distance of the Virgo Cluster, and will allow us to observe many more of the brightest cluster galaxies where the most massive black holes are thought to reside. We also evaluate how well the kinematic moments of the velocity distributions can be constrained at the different spectral resolutions and plate scales designed for IRIS. We find that a spectral resolution of ∼8000 will be necessary to measure the masses of intermediate mass black holes. By simulating the observations of galaxies found in Sloan Digital Sky Survey DR7, we find that over 10{sup 5} massive black holes will be observable at distances between 0.005 < z < 0.18 with the estimated sensitivity and angular resolution provided by access to Z-band (0.9 μm) spectroscopy from IRIS and the TMT adaptive optics system. These observations will provide the most accurate dynamical measurements of black hole masses to

  5. Prospects for Measuring Supermassive Black Hole Masses with Future Extremely Large Telescopes

    NASA Astrophysics Data System (ADS)

    Do, Tuan; Wright, Shelley A.; Barth, Aaron J.; Barton, Elizabeth J.; Simard, Luc; Larkin, James E.; Moore, Anna M.; Wang, Lianqi; Ellerbroek, Brent

    2014-04-01

    The next generation of giant-segmented mirror telescopes (>20 m) will enable us to observe galactic nuclei at much higher angular resolution and sensitivity than ever before. These capabilities will introduce a revolutionary shift in our understanding of the origin and evolution of supermassive black holes by enabling more precise black hole mass measurements in a mass range that is unreachable today. We present simulations and predictions of the observations of nuclei that will be made with the Thirty Meter Telescope (TMT) and the adaptive optics assisted integral-field spectrograph IRIS, which is capable of diffraction-limited spectroscopy from Z band (0.9 μm) to K band (2.2 μm). These simulations, for the first time, use realistic values for the sky, telescope, adaptive optics system, and instrument to determine the expected signal-to-noise ratio of a range of possible targets spanning intermediate mass black holes of ~104 M ⊙ to the most massive black holes known today of >1010 M ⊙. We find that IRIS will be able to observe Milky Way mass black holes out the distance of the Virgo Cluster, and will allow us to observe many more of the brightest cluster galaxies where the most massive black holes are thought to reside. We also evaluate how well the kinematic moments of the velocity distributions can be constrained at the different spectral resolutions and plate scales designed for IRIS. We find that a spectral resolution of ~8000 will be necessary to measure the masses of intermediate mass black holes. By simulating the observations of galaxies found in Sloan Digital Sky Survey DR7, we find that over 105 massive black holes will be observable at distances between 0.005 < z < 0.18 with the estimated sensitivity and angular resolution provided by access to Z-band (0.9 μm) spectroscopy from IRIS and the TMT adaptive optics system. These observations will provide the most accurate dynamical measurements of black hole masses to enable the study of the

  6. The James Webb Telescope Instrument Suite Layout: Optical System Engineering Considerations for a Large, Deployable Space Telescope

    NASA Technical Reports Server (NTRS)

    Bos, Brent; Davila, Pam; Jurotich, Matthew; Hobbs, Gurnie; Lightsey, Paul; Contreras, Jim; Whitman, Tony

    2003-01-01

    The James Webb Space Telescope (JWST) is a space-based, infrared observatory designed to study the early stages of galaxy formation in the Universe. The telescope will be launched into an elliptical orbit about the second Lagrange point and passively cooled to 30-50 K to enable astronomical observations from 0.6 to 28 microns. A group from the NASA Goddard Space Flight Center and the Northrop Grumman Space Technology prime contractor team has developed an optical and mechanical layout for the science instruments within the JWST field of view that satisfies the telescope s high-level performance requirements. Four instruments required accommodation within the telescope's field of view: a Near-Infrared Camera (NIRCam) provided by the University of Arizona; a Near-Mared Spectrometer (NIRSpec) provided by the European Space Agency; a Mid-Infrared Instrument (MIRI) provided by the Jet Propulsion Laboratory and a European consortium; and a Fine Guidance Sensor (FGS) with a tunable filter module provided by the Canadian Space Agency. The size and position of each instrument's field of view allocation were developed through an iterative, concurrent engineering process involving the key observatory stakeholders. While some of the system design considerations were those typically encountered during the development of an infrared observatory, others were unique to the deployable and controllable nature of JWST. This paper describes the optical and mechanical issues considered during the field of view layout development, as well as the supporting modeling and analysis activities.

  7. An atmospheric radiation model for the Very Large Telescope at Cerro Paranal in Chile

    NASA Astrophysics Data System (ADS)

    Noll, S.; Kausch, W.; Barden, M.; Jones, A. M.; Szyszka, C.; Kimeswenger, S.

    2012-04-01

    The quality of ground-based astronomical observations is strongly affected by scattering, absorption, and radiation processes in the Earth's atmosphere. For effective telescope time management, it is important to accurately estimate the wavelength-dependent contribution of the Earth's atmosphere to the observed flux. For this reason we developed an atmospheric radiation model for the Very Large Telescope of the European Southern Observatory at Cerro Paranal in the Atacama desert. It is comprised of all relevant components, i.e. scattered moonlight, scattered starlight, zodiacal light, molecular radiation and absorption in the lower atmosphere, and airglow line and continuum emission in the upper atmosphere. The model covers the entire wavelength range from the near-UV to the mid-IR. Thermal radiation and absorption in the lower atmosphere are computed applying the LBLRTM radiative transfer code and suitable time-averaged atmospheric profiles for the telescope site. Scattered light from extended sources, such as zodiacal light and airglow, is estimated by 3D single scattering calculations and a multiple scattering correction. The intensity and variability of airglow emission lines and continuum is derived by a semi-empirical model based on more than 1000 high signal-to-noise spectra of the FORS1 instrument taken over six years. A comparison of the resulting combined model with observed data yields an accuracy of about 20 per cent, which is a significant improvement over previous models.

  8. The Fermi Large Area Telescope on Orbit: Event Classification, Instrument Response Functions, and Calibration

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Albert, A.; Allafort, A.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Celik, Q.; Cobet, R.; Davis, D. S.; Ferrara, E. C.; Gehrels, N.; Guiriec, S.; McConville, W.; McEnery, J. E.; Nemmen, R.; Perkins, J. S.; Thompson, D. J.

    2012-01-01

    The Fermi Large Area Telescope (Fermi-LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy -ray telescope, covering the energy range from 20 MeV to more than 300 GeV. During the first years of the mission the LAT team has gained considerable insight into the in-flight performance of the instrument. Accordingly, we have updated the analysis used to reduce LAT data for public release as well as the Instrument Response Functions (IRFs), the description of the instrument performance provided for data analysis. In this paper we describe the effects that motivated these updates. Furthermore, we discuss how we originally derived IRFs from Monte Carlo simulations and later corrected those IRFs for discrepancies observed between flight and simulated data. We also give details of the validations performed using flight data and quantify the residual uncertainties in the IRFs. Finally, we describe techniques the LAT team has developed to propagate those uncertainties into estimates of the systematic errors on common measurements such as fluxes and spectra of astrophysical sources.

  9. In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope

    SciTech Connect

    Ackermann, M.; Ajello, M.; Allafort, A.; Atwood, W.B.; Axelsson, M.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; /more authors..

    2012-09-20

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron-plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between {approx}6 and {approx}13 GeV with an estimated uncertainty of {approx}2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.

  10. Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes

    SciTech Connect

    Abdo, A.A.; Ackermann, M.; Ajello, M.; Anderson, B.; Atwood, W.B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B.M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R.D.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bregeon, J.; Brez, A.; Brigida, M.; /more authors..

    2012-04-11

    The diffuse galactic {gamma}-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess {gamma}-ray emission {ge}1 GeV relative to diffuse galactic {gamma}-ray emission models consistent with directly measured CR spectra (the so-called 'EGRET GeV excess'). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse {gamma}-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10{sup o} {le} |b| {le} 20{sup o}. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic {gamma}-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.

  11. Large Scale Refrigeration Plant for Ground Testing the James Webb Telescope at NASA Johnson Space Center

    NASA Astrophysics Data System (ADS)

    Arnold, P.; Decker, Lutz; Howe, D.; Urbin, J.; Homan, Jonathan; Reis, Carl; Creel, J.; Ganni, V.; Knudsen, P.; Sidi-Yekhlef, A.

    2010-04-01

    The James Webb Telescope is the successor to the Hubble Telescope and will be placed in an orbit of 1.5 million km from earth. Before launch in 2014, the telescope will be tested in NASA Johnson Space Center's (JSC) space simulation chamber, Chamber A. The tests will be conducted at deep space conditions. Chamber A's helium cryo-panels are currently cooled down to 20 K by two Linde 3.5 kW helium refrigerators. The new 12.5 kW, 20-K helium coldbox described in this paper is part of the upgrade to the chamber systems for this large test program. The Linde coldbox will provide refrigeration in several operating modes where the temperature of the chamber is being controlled with a high accuracy due to the demanding NASA test requirements. The implementation of two parallel expansion turbine strings and the Ganni cycle-Floating Pressure process results in a highly efficient and flexible process that minimizes the electrical input power. This paper will describe the collaboration and execution of the coldbox project.

  12. Development and testing of an actively controlled large-aperture Cassegrain Telescope for spacecraft deployment

    NASA Astrophysics Data System (ADS)

    Boone, Bradley G.; Bruzzi, Jonathan R.; Kluga, Bernard E.; Rogala, Eric W.; Hale, R. D.; Chen, Peter C.

    2004-10-01

    The National Aeronautics and Space Administration (NASA) is planning future deep space missions requiring space-based imaging reconnaissance of planets and recovery of imagery from these missions via optical communications. Both applications have similar requirements that can be met by a common aperture. The Johns Hopkins University Applied Physics Laboratory in collaboration with commercial and academic partners is developing a new approach to deploying and controlling large aperture (meter-class) optical telescopes on spacecraft that can be rapidly launched and deployed. The deployment mechanism uses flexible longeron struts to deploy the secondary. The active control system uses a fiber-coupled laser array near the focal plane that reflects four collimated laser beams off of the periphery of the secondary to four equally-disposed quad cell sensors at the periphery of the primary to correct secondary-to-primary misalignments and enable motion compensation. We describe a compensation technique that uses tip/tilt and piston actuators for quasi-static bias correction and dynamic motion compensation. We also describe preliminary optical tests using a commercial Schmidt-Cassegrain telescope in lieu of an ultra-lightweight composite Cassegrain, which is under development by Composite Mirror Applications, Inc. Finite element and ray trace modeling results for a 40 cm composite telescope design will also be described.

  13. Analysis of normalized point source sensitivity as a performance metric for large telescopes.

    PubMed

    Seo, Byoung-Joon; Nissly, Carl; Angeli, George; Ellerbroek, Brent; Nelson, Jerry; Sigrist, Norbert; Troy, Mitchell

    2009-11-01

    We investigate a new metric, the normalized point source sensitivity (PSSN), for characterizing the seeing-limited performance of large telescopes. As the PSSN metric is directly related to the photometric error of background limited observations, it represents the efficiency loss in telescope observing time. The PSSN metric properly accounts for the optical consequences of wave front spatial frequency distributions due to different error sources, which differentiates from traditional metrics such as the 80% encircled energy diameter and the central intensity ratio. We analytically show that multiplication of individual PSSN values due to individual errors is a good approximation for the total PSSN when various errors are considered simultaneously. We also numerically confirm this feature for Zernike aberrations as well as for the numerous error sources considered in the error budget of the Thirty Meter Telescope (TMT) using a ray optics simulator. Additionally, we discuss other pertinent features of the PSSN, including its relations to Zernike aberration, RMS wave front error, and central intensity ratio.

  14. In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Allafort, A.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Barbielini, G; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B,; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Gehrels, N.; Hays, E.; McEnery, J. E.; Thompson, D. J.; Troja, E. J.

    2012-01-01

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron- plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between approx. 6 and approx. 13 GeV with an estimated uncertainty of approx. 2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.

  15. THE FERMI LARGE AREA TELESCOPE ON ORBIT: EVENT CLASSIFICATION, INSTRUMENT RESPONSE FUNCTIONS, AND CALIBRATION

    SciTech Connect

    Ackermann, M.; Ajello, M.; Allafort, A.; Bechtol, K.; Blandford, R. D.; Bloom, E. D.; Bogart, J. R.; Borgland, A. W.; Bottacini, E.; Albert, A.; Atwood, W. B.; Bouvier, A.; Axelsson, M.; Baldini, L.; Ballet, J.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Bonamente, E. E-mail: luca.baldini@pi.infn.it; and others

    2012-11-15

    The Fermi Large Area Telescope (Fermi-LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy {gamma}-ray telescope, covering the energy range from 20 MeV to more than 300 GeV. During the first years of the mission, the LAT team has gained considerable insight into the in-flight performance of the instrument. Accordingly, we have updated the analysis used to reduce LAT data for public release as well as the instrument response functions (IRFs), the description of the instrument performance provided for data analysis. In this paper, we describe the effects that motivated these updates. Furthermore, we discuss how we originally derived IRFs from Monte Carlo simulations and later corrected those IRFs for discrepancies observed between flight and simulated data. We also give details of the validations performed using flight data and quantify the residual uncertainties in the IRFs. Finally, we describe techniques the LAT team has developed to propagate those uncertainties into estimates of the systematic errors on common measurements such as fluxes and spectra of astrophysical sources.

  16. Status of Technology Development to enable Large Stable UVOIR Space Telescopes

    NASA Astrophysics Data System (ADS)

    Stahl, H. Philip; MSFC AMTD Team

    2017-01-01

    NASA MSFC has two funded Strategic Astrophysics Technology projects to develop technology for potential future large missions: AMTD and PTC. The Advanced Mirror Technology Development (AMTD) project is developing technology to make mechanically stable mirrors for a 4-meter or larger UVOIR space telescope. AMTD is demonstrating this technology by making a 1.5 meter diameter x 200 mm thick ULE(C) mirror that is 1/3rd scale of a full size 4-m mirror. AMTD is characterizing the mechanical and thermal performance of this mirror and of a 1.2-meter Zerodur(R) mirror to validate integrate modeling tools. Additionally, AMTD has developed integrated modeling tools which are being used to evaluate primary mirror systems for a potential Habitable Exoplanet Mission and analyzed the interaction between optical telescope wavefront stability and coronagraph contrast leakage. Predictive Thermal Control (PTC) project is developing technology to enable high stability thermal wavefront performance by using integrated modeling tools to predict and actively control the thermal environment of a 4-m or larger UVOIR space telescope.

  17. Gain and Polarization Properties of a Large Radio Telescope from Calculation and Measurement: The John A. Galt Telescope

    NASA Astrophysics Data System (ADS)

    Du, X.; Landecker, T. L.; Robishaw, T.; Gray, A. D.; Douglas, K. A.; Wolleben, M.

    2016-11-01

    Measurement of the brightness temperature of extended radio emission demands knowledge of the gain (or aperture efficiency) of the telescope and measurement of the polarized component of the emission requires correction for the conversion of unpolarized emission from sky and ground to apparently polarized signal. Radiation properties of the John A. Galt Telescope at the Dominion Radio Astrophysical Observatory were studied through analysis and measurement in order to provide absolute calibration of a survey of polarized emission from the entire northern sky from 1280 to 1750 MHz, and to understand the polarization performance of the telescope. Electromagnetic simulation packages CST and GRASP-10 were used to compute complete radiation patterns of the telescope in all Stokes parameters, and thereby to establish gain and aperture efficiency. Aperture efficiency was also evaluated using geometrical optics and ray tracing analysis and was measured based on the known flux density of Cyg A. Measured aperture efficiency varied smoothly with frequency between values of 0.49 and 0.54; GRASP-10 yielded values 6.5% higher but with closely similar variation with frequency. Overall error across the frequency band is 3%, but values at any two frequencies are relatively correct to ∼1%. Dominant influences on aperture efficiency are the illumination taper of the feed radiation pattern and the shadowing of the reflector from the feed by the feed-support struts. A model of emission from the ground was developed based on measurements and on empirical data obtained from remote sensing of the Earth from satellite-borne telescopes. This model was convolved with the computed antenna response to estimate conversion of ground emission into spurious polarized signal. The computed spurious signal is comparable to measured values, but is not accurate enough to be used to correct observations. A simpler model, in which the ground is considered as an unpolarized emitter with a brightness

  18. A segmented subreflector with electroformed nickel laminated panels for the Large Millimeter Telescope

    NASA Astrophysics Data System (ADS)

    Valsecchi, G.; Banham, R.; Bianucci, G.; Eder, J.; Ghislanzoni, R.; Ritucci, A.; Terraneo, M.; Zocchi, F. E.; Smith, D.; Gale, D.; Hughes, D.

    2016-07-01

    The Large Millimeter Telescope (LMT) Alfonso Serrano is a 50 m diameter single-dish radio telescope optimized for astronomical observations at wavelengths of about a millimeter. Built and operated by the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) in collaboration with the University of Massachusetts (UMASS), the telescope is located at the 4600 m summit of volcano Sierra Negra, Mexico. Anticipating the completion of the main reflector, currently operating over a 32 m subaperture, INAOE has contracted Media Lario for the design and manufacturing of a new 2.63 m subreflector that will enable higher efficiency astronomical observations with the entire main reflector surface. The new subreflector manufactured by Media Lario is segmented in 9 smaller panels, one central dome and eight identical petals, assembled and precisely aligned on a steel truss structure that will be connected to the hexapod mounted on the tetrapod head. Each panel was fabricated with Media Lario's unique laminated technology consisting of front and rear Nickel skins, electroformed from precise molds and bonded to a lightweight Aluminum honeycomb core. The reflecting surface of each panel was given a thin galvanic Rhodium coating that ensures that the reflector survives the harsh environmental conditions at the summit of Sierra Negra during the 30 year lifetime of the telescope. Finally, the 2.63 m subreflector produced by Media Lario was qualified for typical cold night through hot day observation conditions with a maximum RMS error of 24.8 μm, which meets INAOE's requirements.

  19. Indirect searches for dark matter with the Fermi large area telescope

    DOE PAGES

    Albert, Andrea

    2015-03-24

    There is overwhelming evidence that non-baryonic dark matter constitutes ~ 27% of the energy density of the Universe. Weakly Interacting Massive Particles (WIMPs) are promising dark matter candidates that may produce γ rays via annihilation or decay detectable by the Fermi Large Area Telescope (LAT). A detection of WIMPs would also indicate the existence of physics beyond the Standard Model. We present recent results from the two cleanest indirect WIMP searches by the Fermi-LAT Collaboration: searches for γ-ray spectral lines and γ-ray emission associated with Milky Way dwarf spheroidal satellite galaxies.

  20. Collimator equipment of the Large Optical Test Facility Vertical for testing space telescopes

    NASA Astrophysics Data System (ADS)

    Sergeev, Pavel A.; Gogolev, Yuri A.; Zvonkova, V. V.; Kobozev, I. R.; Ostapenko, S. V.; Malamed, Evgeny R.; Demidov, V. V.

    1995-06-01

    This paper is concerned with the collimator equipment of the large optical test facility (LOTF) 'vertical' designed for testing space telescopes. It is being created in the Research Center 'S.I. Vavilov State Optical Institute' in Russia. The optical scheme and special structural features of the vacuum vertical-type double-mirror collimator will be covered here. This paper deals with technical data and potentials of collimator focal equipment. Estimations of the collimator thermal aberrations caused by temperature fields coming from thermal simulators are put forward.

  1. Design and Characteristics of the Anticoincidence Detector for the GLAST Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Moiseev, A. A.; Hartman, R. C.; Johnson, T. E.; Ormes, J. F.; Thompson, D. J.

    2005-01-01

    The Anti-Coincidence Detector (ACD) is the outermost detector layer in the GLAST Large Area Telescope (LAT), surrounding the top and sides of the tracker. The purpose of the ACD is to detect and veto incident cosmic ray charged particles, which outnumber cosmic gamma rays by 3-4 orders of magnitude. The challenge in ACD design is that it must have high (0.9997) detection efficiency for singly charged relativistic particles, but must also have low sensitivity to backsplash particles. These are products of high- energy interactions in the LAT calorimeter. They can cause a veto signal in the ACD, resulting in loss of good gamma-ray events.

  2. Indirect searches for dark matter with the Fermi large area telescope

    SciTech Connect

    Albert, Andrea

    2015-03-24

    There is overwhelming evidence that non-baryonic dark matter constitutes ~ 27% of the energy density of the Universe. Weakly Interacting Massive Particles (WIMPs) are promising dark matter candidates that may produce γ rays via annihilation or decay detectable by the Fermi Large Area Telescope (LAT). A detection of WIMPs would also indicate the existence of physics beyond the Standard Model. We present recent results from the two cleanest indirect WIMP searches by the Fermi-LAT Collaboration: searches for γ-ray spectral lines and γ-ray emission associated with Milky Way dwarf spheroidal satellite galaxies.

  3. Data reductions and data quality for the high resolution spectrograph on the Southern African Large Telescope

    NASA Astrophysics Data System (ADS)

    Crawford, S. M.; Crause, Lisa; Depagne, Éric; Ilkiewicz, Krystian; Schroeder, Anja; Kuhn, Rudolph; Hettlage, Christian; Romero Colmenaro, Encarni; Kniazev, Alexei; Väisänen, Petri

    2016-08-01

    The High Resolution Spectrograph (HRS) on the Southern African Large Telescope (SALT) is a dual beam, fiber-fed echelle spectrograph providing high resolution capabilities to the SALT observing community. We describe the available data reduction tools and the procedures put in place for regular monitoring of the data quality from the spectrograph. Data reductions are carried out through the pyhrs package. The data characteristics and instrument stability are reported as part of the SALT Dashboard to help monitor the performance of the instrument.

  4. Spacecraft Conceptual Design for the 8-Meter Advanced Technology Large Aperture Space Telescope (ATLAST)

    NASA Technical Reports Server (NTRS)

    Hopkins, Randall C.; Capizzo, Peter; Fincher, Sharon; Hornsby, Linda S.; Jones, David

    2010-01-01

    The Advanced Concepts Office at Marshall Space Flight Center completed a brief spacecraft design study for the 8-meter monolithic Advanced Technology Large Aperture Space Telescope (ATLAST-8m). This spacecraft concept provides all power, communication, telemetry, avionics, guidance and control, and thermal control for the observatory, and inserts the observatory into a halo orbit about the second Sun-Earth Lagrange point. The multidisciplinary design team created a simple spacecraft design that enables component and science instrument servicing, employs articulating solar panels for help with momentum management, and provides precise pointing control while at the same time fast slewing for the observatory.

  5. The Silicon Tracker Readout Electronics of the Gamma-ray Large Area Space Telescope

    SciTech Connect

    Baldini, Luca; Brez, Alessandro; Himel, Thomas; Hirayama, Masaharu; Johnson, R.P.; Kroeger, Wilko; Latronico, Luca; Minuti, Massimo; Nelson, David; Rando, Riccardo; Sadrozinski, H.F.-W.; Sgro, Carmelo; Spandre, Gloria; Spencer, E.N.; Sugizaki, Mutsumi; Tajima, Hiro; Cohen-Tanugi, Johann; Ziegler, Marcus; /Pisa U. /INFN, Pisa /SLAC /Maryland U. /UC, Santa Cruz /Padua U. /INFN, Padua

    2006-02-27

    A unique electronics system has been built and tested for reading signals from the silicon-strip detectors of the Gamma-ray Large Area Space Telescope mission. The system amplifies and processes signals from 884,736 36-cm strips using only 160 W of power, and it achieves close to 100% detection efficiency with noise occupancy sufficiently low to allow it to self trigger. The design of the readout system is described, and results are presented from ground-based testing of the completed detector system.

  6. Optimal fine pointing control of a large space telescope using an Annular Momentum Control Device

    NASA Technical Reports Server (NTRS)

    Nadkarni, A. A.; Joshi, S. M.; Groom, N. J.

    1977-01-01

    This paper discusses the application of an Annular Momentum Control Device (AMCD) to fine pointing control of a large space telescope (LST). The AMCD represents a new development in the field of momentum storage devices. A linearized mathematical model is developed for the AMCD/LST system, including the magnetic suspension actuators. Two approaches to control system design are considered. The first approach uses a stochastic linear-quadratic Gaussian controller which utilizes feedback of all states. The second approach considers a more practical control system design in which the axial and radial loops are designed independently.

  7. Differential focal anisoplanatism in laser guide star wavefront sensing on extremely large telescopes.

    PubMed

    Muller, Nicolas; Michau, Vincent; Robert, Clélia; Rousset, Gérard

    2011-10-15

    Laser guide stars (LGSs) aim at increasing the sky coverage of adaptive optics (AO) as this is highly restricted when using only natural guide stars. With such three-dimensional extended objects, spot elongation may limit the measurement accuracy of wavefronts. We evaluate the effect of differential focal anisoplanatism, induced solely by the longitudinal extension of a side-launched LGS, on the slope measurements performed by a Shack-Hartmann for a 40 m class telescope. We also take this effect into account in the wavefront reconstruction and derive estimations of the resulting wavefront error in a multi-LGS AO system. We find an error of 100 nm in the worst case at the subaperture level and a small error of the order of 10 nm for six LGSs after wavefront reconstruction.

  8. Towards a State Based Control Architecture for Large Telescopes: Laying a Foundation at the VLT

    NASA Technical Reports Server (NTRS)

    Karban, R.; Kornweibel, N.; Dvorak, D.; Ingham, M.; Wagner, D.

    2011-01-01

    Large telescopes are characterized by a high level of distribution of control-related tasks and will feature diverse data flow patterns and large ranges of sampling frequencies; there will often be no single, fixed server-client relationship between the control tasks. the architecture is also challenged by the task of integrating heterogeneous subsystems which will be delivered by multiple different contractors. Due to the high number of distributed components, the control system needs to effectively detect errors and faults, impede their propagation, and accurately mitigate them in the shortest time possible, enabling the service to be restored. The presented Data-Driven Architecture is based on a decentralized approach with an end-to-end integration of disparate, independently developed software components. These components employ a high-performance standards-based communication middle-ware infrastructure, based on the Data Distribution Service. A set of rules and principles, based on JPL's State Analysis method and architecture, are use to constrain component-to component interactions, where the Control System and System Under Control are clearly separated. State Analysis provide a model-based process for capturing system and software requirements and design, greatly reducing the gap between the requirements on software specified by systems engineers and the implementation by software engineers. The method and architecture has been field tested at the Very Large Telescope, where it has been integrated into an operational system.

  9. The Capabilities of the GLAST Large Area Telescope for Blazar Variability Studies

    NASA Technical Reports Server (NTRS)

    McEnery, Julie

    2006-01-01

    One of the more notable features of the Large Area Telescope (LAT) on GLAST is its extremely large field of view, which covers more than 20% of the sky at any instant. In survey mode the LAT will be rocked about the orbital plane to provide coverage of the entire gamma-ray sky above 20 MeV every three hours. This will be the default observing mode for the first year of operations and is likely to be the dominant observing mode throughout the rest of the mission. Thus the LAT will provide long, evenly sampled, gamma-ray lightcurves for a large number of sources. In this talk we describe the nature and quality of the data that will be provided by the LAT and use simulated lightcurves to illustrate some of the scientific questions that can be addressed with LAT observations.

  10. The optical design of a visible adaptive optics system for the Magellan Telescope

    NASA Astrophysics Data System (ADS)

    Kopon, Derek

    The Magellan Adaptive Optics system will achieve first light in November of 2012. This AO system contains several subsystems including the 585-actuator concave adaptive secondary mirror, the Calibration Return Optic (CRO) alignment and calibration system, the CLIO 1-5 microm IR science camera, the movable guider camera and active optics assembly, and the W-Unit, which contains both the Pyramid Wavefront Sensor (PWFS) and the VisAO visible science camera. In this dissertation, we present details of the design, fabrication, assembly, alignment, and laboratory performance of the VisAO camera and its optical components. Many of these components required a custom design, such as the Spectral Differential Imaging Wollaston prisms and filters and the coronagraphic spots. One component, the Atmospheric Dispersion Corrector (ADC), required a unique triplet design that had until now never been fabricated and tested on sky. We present the design, laboratory, and on-sky results for our triplet ADC. We also present details of the CRO test setup and alignment. Because Magellan is a Gregorian telescope, the ASM is a concave ellipsoidal mirror. By simulating a star with a white light point source at the far conjugate, we can create a double-pass test of the whole system without the need for a real on-sky star. This allows us to test the AO system closed loop in the Arcetri test tower at its nominal design focal length and optical conjugates. The CRO test will also allow us to calibrate and verify the system off-sky at the Magellan telescope during commissioning and periodically thereafter. We present a design for a possible future upgrade path for a new visible Integral Field Spectrograph. By integrating a fiber array bundle at the VisAO focal plane, we can send light to a pre-existing facility spectrograph, such as LDSS3, which will allow 20 mas spatial sampling and R˜1,800 spectra over the band 0.6-1.05 microm. This would be the highest spatial resolution IFU to date, either

  11. Current status of the facility instrumentation suite at the Large Binocular Telescope Observatory

    NASA Astrophysics Data System (ADS)

    Rothberg, Barry; Kuhn, Olga; Edwards, Michelle L.; Hill, John M.; Thompson, David; Veillet, Christian; Wagner, R. Mark

    2016-07-01

    The current status of the facility instrumentation for the Large Binocular Telescope (LBT) is reviewed. The LBT encompasses two 8.4 meter primary mirrors on a single mount yielding an effective collecting area of 11.8 meters or 23 meters when interferometrically combined. The three facility instruments at LBT include: 1) the Large Binocular Cameras (LBCs), each with a 23'× 25' field of view (FOV). The blue optimized and red optimized optical wavelength LBCs are mounted at the prime focus of the SX (left) and DX (right) primary mirrors, respectively. Combined, the filter suite of the two LBCs cover 0.3-1.1 μm, including the addition of new medium-band filters centered on TiO (0.78 μm) and CN (0.82 μm) 2) the Multi-Object Double Spectrograph (MODS), two identical optical spectrographs each mounted at the straight through f/15 Gregorian focus of the primary mirrors. The capabilities of MODS-1 and -2 include imaging with Sloan filters (u, g, r, i, and z) and medium resolution (R ˜ 2000) spectroscopy, each with 24 interchangeable masks (multi-object or longslit) over a 6'× 6' FOV. Each MODS is capable of blue (0.32-0.6 μm) and red (0.5-1.05 μm) wavelength only spectroscopy coverage or both can employ a dichroic for 0.32-1.05 μm wavelength coverage (with reduced coverage from 0.56- 0.57 μm) and 3) the two LBT Utility Camera in the Infrared instruments (LUCIs), are each mounted at a bent-front Gregorian f/15 focus of a primary mirror. LUCI-1 and 2 are designed for seeing-limited (4'× 4' FOV) and active optics using thin-shell adaptive secondary mirrors (0.5'× 0.5' FOV) imaging and spectroscopy over the wavelength range of 0.95-2.5 μm and spectroscopic resolutions of 400 <= R <= 11000 (depending on the combination of grating, slits, and cameras used). The spectroscopic capabilities also include 32 interchangeable multi-object or longslit masks which are cryogenically cooled. Currently all facility instruments are in-place at the LBT and, for the first time

  12. Large Format Si:As IBC Array Performance for NGST and Future IR Space Telescope Applications

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Johnson, Roy; Love, Peter; Lum, Nancy; McKelvey, Mark; McCreight, Craig; McMurray, Robert, Jr.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    A mid-IR (5-30micrometer) instrument aboard a cryogenic space telescope can have an enormous impact in resolving key questions in astronomy and cosmology. A space platform's greatly reduced thermal backgrounds (compared to airborne or ground-based platforms), allow for more sensitive observations of dusty young galaxies at high redshifts, star formation of solar-type stars in the local universe, and formation and evolution of planetary disks and systems. The previous generation's largest, in sensitive IR detectors at these wavelengths are 256x256 pixel Si:As Impurity Band Conduction (IBC) devices built by Raytheon Infrared Operations (RIO) for the Space Infrared Telescope Facility/Infrared Array Camera (SIRTF)/(IRAC) instrument. RIO has successfully enhanced these devices, increasing the pixel count by a factor of 16 while matching or exceeding SIRTF/IRAC device performance. NASA-ARC in collaboration with RIO has tested the first high performance large format (1024x 1024) Si:As IBC arrays for low background applications, such as for the middle instrument on Next Generation Space Telescope (NGST) and future IR Explorer missions. These hybrid devices consist of radiation hard SIRTF/IRAC-type Si:As IBC material mated to a readout multiplexer that has been specially processed for operation at low cryogenic temperatures (below 10K), yielding high device sensitivity over a wavelength range of 5-28 micrometers. We present laboratory testing results from these benchmark, devices. Continued development in this technology is essential for conducting large-area surveys of the local and early universe through observation and for complementing future missions such as NGST, Terrestrial Planet Finder (TPF), and Focal Plane Instruments and Requirement Science Team (FIRST).

  13. Advanced UVOIR Mirror Technology Development (AMTD) for Very Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Postman, Marc; Soummer, Remi; Sivramakrishnan, Annand; Macintosh, Bruce; Guyon, Olivier; Krist, John; Stahl, H. Philip; Smith, W. Scott; Mosier, Gary; Kirk, Charles; Arnold, William

    2013-01-01

    ASTRO2010 Decadal Survey stated that an advanced large-aperture ultraviolet, optical, near-infrared (UVOIR) telescope is required to enable the next generation of compelling astrophysics and exoplanet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. AMTD is the start of a multiyear effort to develop, demonstrate and mature critical technologies to TRL-6 by 2018 so that a viable flight mission can be proposed to the 2020 Decadal Review. AMTD builds on the state of art (SOA) defined by over 30 years of monolithic & segmented ground & space-telescope mirror technology to mature six key technologies: (1) Large-Aperture, Low Areal Density, High Stiffness Mirror Substrates: Both (4 to 8 m) monolithic and (8 to 16 m) segmented primary mirrors require larger, thicker, and stiffer substrates. (2) Support System: Large-aperture mirrors require large support systems to ensure that they survive launch and deploy on orbit in a stress-free and undistorted shape. (3) Mid/High Spatial Frequency Figure Error: Very smooth mirror is critical for producing high-quality point spread function (PSF) for high contrast imaging. (4) Segment Edges: The quality of segment edges impacts PSF for high-contrast imaging applications, contributes to stray light noise, and affects total collecting aperture. (5) Segment to Segment Gap Phasing: Segment phasing is critical for producing high-quality temporally-stable PSF. (6) Integrated Model Validation: On-orbit performance is driven by mechanical & thermal stability. Compliance cannot be 100% tested, but relies on modeling. AMTD is pursuing multiple design paths to provide the science community with options to enable either large aperture monolithic or segmented mirrors with clear engineering metrics traceable to science requirements.

  14. A New Large Vibration Test Facility Concept for the James Webb Space Telescope

    NASA Technical Reports Server (NTRS)

    Ross, Brian P.; Johnson, Eric L.; Hoksbergen, Joel; Lund, Doug

    2014-01-01

    The James Webb Space Telescope consists of three main components, the Integrated Science Instrument Module (ISIM) Element, the Optical Telescope Element (OTE), and the Spacecraft Element. The ISIM and OTE are being assembled at the National Aeronautics and Space Administration's Goddard Spaceflight Center (GSFC). The combined OTE and ISIM Elements, called OTIS, will undergo sine vibration testing before leaving Goddard. OTIS is the largest payload ever tested at Goddard and the existing GSFC vibration facilities are incapable of performing a sine vibration test of the OTIS payload. As a result, a new large vibration test facility is being designed. The new facility will consist of a vertical system with a guided head expander and a horizontal system with a hydrostatic slip table. The project is currently in the final design phase with installation to begin in early 2015 and the facility is expected to be operational by late 2015. This paper will describe the unique requirements for a new large vibration test facility and present the selected final design concepts.

  15. GLAST LARGE AREA TELESCOPE: DAILY SURVEY OF HIGH-ENERGY SKY

    SciTech Connect

    Kamae, T

    2003-12-12

    GLAST Large Area Telescope was proposed to NASA in 1999 as follow-up of EGRET on-board Compton Gamma-Ray Observatory by an international collaboration. The proposal has been approved as a part of the GLAST observatory mission in its capability to explore w die range of astrophysics with 5-40 times higher sensitivity and extended energy coverage (20 MeV to 300 GeV) than EGRET. The instrument consists of 16 towers of e{sup +}e{sup -} pair tracker, 16 blocks of segmented electro-magnetic calorimeter, and a st of anti-coincidence plastic scintillator tiles covering the tracker towers. It will have 5-10 times larger on-axis effective area, 6 times wider field-of-view (FOV), and up to 5 times better angular resolution when compared with EGRET. The Large Area Telescope will cover about 40% of the sky above the Earth's horizon in its FOV at any given time and will scan nearly the entire Universe every orbit ({approx} 90min): about 20% of Gamma-Ray Bursts will be observed from the onset of the bursts to the initial after-glow phase; all longer-lasting transients and variabilities will be detected daily at the improved sensitivity.

  16. Science Enabled by the Ares V: A Large Monolithic Telescope Placed at the Second Sun-Earth Lagrange Point

    NASA Technical Reports Server (NTRS)

    Hopkins, Randall C.; Stahl, H. Philip

    2007-01-01

    The payload mass and volume capabilities of the planned Ares V launch vehicle provide the science community with unprecedented opportunities to place large science payloads into low earth orbit and beyond. One example, the outcome of a recent study conducted at the NASA Marshall Space Flight Center, is a large, monolithic telescope with a primary mirror diameter of 6.2 meters placed into a halo orbit about the second Sun-Earth Lagrange point, or L2, approximately 1.5 million kin beyond Earth's orbit. Operating in the visible and ultraviolet regions of the electromagnetic spectrum, such a large telescope would allow astronomers to detect bio-signatures and characterize the atmospheres of transiting exoplanets, provide high resolution imaging three or more times better than the Hubble Space Telescope and the James Webb Space Telescope, and observe the ultraviolet light from warm baryonic matter.

  17. Adaptive optics imaging of QSO host galaxies with Hokupa'a on the Gemini North telescope

    NASA Astrophysics Data System (ADS)

    Guyon, O.; Sanders, D. B.; Stockton, A.; Baudoz, P.; Potter, D.

    2001-05-01

    We report the initial results of a new near-infrared imaging survey of quasar hosts using the University of Hawaii Hokupa'a Adaptive Optics system on the 8.2m Gemini-North telescope. J,H,K' images of a complete subsample ( 25) of nearby (z <0.3), "bona-fide" optically selected (MB < -23; Ho = 50, qo=0; Schmidt & Green 1983) QSOs are being taken in order to obtain accurate host galaxy magnitudes and colors and to determine two-dimensional structure. In the initial phase of our observations we found that PSF subtraction residuals were severely limiting our ability to characterize the host galaxy. However we were able to obtain a significant increase in stability of the PSF by turning off the Cassegrain rotator during observations (see Roth et al. contribution at this meeting). Our sample of Palomar-Green Bright QSOs includes both radio quiet and radio loud objects plus objects spanning the full range of observed "infrared excess" continuum emission. One of the most surprising results has been the detection of modest scale (3-5" 5 kpc diameter) "bars" and/or circumnuclear "disks" that were not evident in previous one-dimensional profile analyses. These structures may be related to the reservoir of fuel needed to power the QSO and may provide important clues concerning the origin and evolution of QSO hosts.

  18. KAPAO: A Natural Guide Star Adaptive Optics System for Small Aperture Telescopes

    NASA Astrophysics Data System (ADS)

    Severson, Scott A.; Choi, P. I.; Spjut, E.; Contreras, D. S.; Gilbreth, B. N.; McGonigle, L. P.; Morrison, W. A.; Rudy, A. R.; Xue, A.; Baranec, C.; Riddle, R.

    2012-05-01

    We describe KAPAO, our project to develop and deploy a low-cost, remote-access, natural guide star adaptive optics system for the Pomona College Table Mountain Observatory (TMO) 1-meter telescope. The system will offer simultaneous dual-band, diffraction-limited imaging at visible and near-infrared wavelengths and will deliver an order-of-magnitude improvement in point source sensitivity and angular resolution relative to the current TMO seeing limits. We have adopted off-the-shelf core hardware components to ensure reliability, minimize costs and encourage replication efforts. These components include a MEMS deformable mirror, a Shack-Hartmann wavefront sensor and a piezo-electric tip-tilt mirror. We present: project motivation, goals and milestones; the instrument optical design; the instrument opto-mechanical design and tolerances; and an overview of KAPAO Alpha, our on-the-sky testbed using off-the-shelf optics. Beyond the expanded scientific capabilities enabled by AO-enhanced resolution and sensitivity, the interdisciplinary nature of the instrument development effort provides an exceptional opportunity to train a broad range of undergraduate STEM students in AO technologies and techniques. The breadth of our collaboration, which includes both public (Sonoma State University) and private (Pomona and Harvey Mudd Colleges) undergraduate institutions has enabled us to engage students ranging from physics, astronomy, engineering and computer science in the all stages of this project. This material is based upon work supported by the National Science Foundation under Grant No. 0960343.

  19. KAPAO-Alpha: An On-The-Sky Testbed for Adaptive Optics on Small Aperture Telescopes

    NASA Astrophysics Data System (ADS)

    Morrison, Will; Choi, P. I.; Severson, S. A.; Spjut, E.; Contreras, D. S.; Gilbreth, B. N.; McGonigle, L. P.; Rudy, A. R.; Xue, A.; Baranec, C.; Riddle, R.

    2012-05-01

    We present initial in-lab and on-sky results of a natural guide star adaptive optics instrument, KAPAO-Alpha, being deployed on Pomona College’s 1-meter telescope at Table Mountain Observatory. The instrument is an engineering prototype designed to help us identify and solve design and integration issues before building KAPAO, a low-cost, dual-band, natural guide star AO system currently in active development and scheduled for first light in 2013. The Alpha system operates at visible wavelengths, employs Shack-Hartmann wavefront sensing, and is assembled entirely from commercially available components that include: off-the-shelf optics, a 140-actuator BMC deformable mirror, a high speed SciMeasure Lil’ Joe camera, and an EMCCD for science image acquisition. Wavefront reconstruction operating at 1-kHz speeds is handled with a consumer-grade computer running custom software adopted from the Robo-AO project. The assembly and integration of the Alpha instrument has been undertaken as a Pomona College undergraduate thesis. As part of the larger KAPAO project, it is supported by the National Science Foundation under Grant No. 0960343.

  20. Diffractive imaging analysis of large-aperture segmented telescope based on partial Fourier transform

    NASA Astrophysics Data System (ADS)

    Dong, Bing; Qin, Shun; Hu, Xinqi

    2013-09-01

    Large-aperture segmented primary mirror will be widely used in next-generation space-based and ground-based telescopes. The effects of intersegment gaps, obstructions, position and figure errors of segments, which are all involved in the pupil plane, on the image quality metric should be analyzed using diffractive imaging theory. Traditional Fast Fourier Transform (FFT) method is very time-consuming and costs a lot of memory especially in dealing with large pupil-sampling matrix. A Partial Fourier Transform (PFT) method is first proposed to substantially speed up the computation and reduce memory usage for diffractive imaging analysis. Diffraction effects of a 6-meter segmented mirror including 18 hexagonal segments are simulated and analyzed using PFT method. The influence of intersegment gaps and position errors of segments on Strehl ratio is quantitatively analyzed by computing the Point Spread Function (PSF). By comparing simulation results with theoretical results, the correctness and feasibility of PFT method is confirmed.

  1. Technical considerations on using the large Nancay radio telescope for SETI

    NASA Technical Reports Server (NTRS)

    Gulkis, S.; Biraud, F.; Heidmann, J.; Tarter, J.

    1990-01-01

    The Nancay decimetric Radio Telescope (NRT) in Nancay, France, is described, and its potential use for Search for Extraterrestrial Intelligence (SETI) observations is discussed. The conclusion reached is that the NRT is well suited for SETI observations because of its large collecting area, its large sky coverage, and its wideband frequency capability. However, a number of improvements are necessary in order to take full advantage of the system in carrying out an efficient SETI program. In particular, system sensitivity should be increased. This can be achieved through a series of improvements to the system, including lowering the ground pickup noise through the use of ground reflectors and more efficient feed design, and by using low-noise amplifier front ends.

  2. Measurement of the cosmic-ray proton spectrum with the Fermi Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Green, David; Fermi LAT Area Telescope Collaboration Collaboration

    2017-01-01

    We present the measurement of the cosmic-ray proton spectrum between 54 GeV and 9.5 TeV using 7 years of Pass 8 flight data from the Fermi Large Area Telescope (LAT). We developed a dedicated proton event selection with an acceptance of 0.25 m2 sr. Our analysis yields a large dataset with low statistical uncertainty and low residual contamination for a spectral measurement. The systematic errors associated with the acceptance, energy measurement, GEANT4 Monte-Carlo simulations are an order of magnitude larger than the statistical uncertainty. The event selection and spectral measurement of the proton analysis create the opportunity for additional proton analyses with the LAT, such as a dedicated proton anisotropy search.

  3. Characterization and acceptance testing of fully depleted thick CCDs for the large synoptic survey telescope

    NASA Astrophysics Data System (ADS)

    Kotov, Ivan V.; Haupt, Justine; O'Connor, Paul; Smith, Thomas; Takacs, Peter; Neal, Homer; Chiang, Jim

    2016-07-01

    The Large Synoptic Survey Telescope (LSST) camera will be made as a mosaic assembled of 189 large format Charge Coupled Devices (CCD). They are n-channel, 100 micron thick devices operated in the over depleted regime. There are 16 segments, 1 million pixels each, that are read out through separate amplifiers. The image quality and readout speed expected from LSST camera translates into strict acceptance requirements for individual sensors. Prototype sensors and preproduction CCDs were delivered by vendors and they have been used for developing test procedures and protocols. Building upon this experience, two test stands were designed and commissioned at Brookhaven National Laboratory for production electro-optical testing. In this article, the sensor acceptance criteria are outlined and discussed, the test stand design and used equipment are presented and the results from commissioning sensor runs are shown.

  4. The Gamma-ray Large Area Space Telescope (GLAST): Status and Plans

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2008-01-01

    The Gamma-ray Large Area Space Telescope, GLAST, is a mission to measure the cosmic gamma-ray flux in the energy range 20 MeV to >300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. The very large field of view makes it possible to observe 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its recent launch on 11 June, GLAST now opens a new and important window on a wide variety of phenomena, including black holes and active galactic nuclei; the optical-UV extragalactic background light, gamma-ray bursts: the origin of cosmic rays and supernova remnants; and searches for hypothetical new phenomena such as supersymmetric dark matter annihilations. In addition to the science opportunities, this talk includes a description of the instruments and the mission status and plans.

  5. SPITZER, VERY LARGE TELESCOPE, AND VERY LARGE ARRAY OBSERVATIONS OF THE GALACTIC LUMINOUS BLUE VARIABLE CANDIDATE HD 168625

    SciTech Connect

    Umana, G.; Buemi, C. S.; Trigilio, C.; Leto, P.; Hora, J. L.

    2010-08-01

    We present mid-IR and radio observations of the Galactic luminous blue variables (LBVs) candidate HD 168625 and its associated nebula. We obtained mid-IR spectroscopic observations using the Infrared Spectrograph on board the Spitzer Space Telescope, and performed mid-IR and radio imaging observations using VISIR on the Very Large Telescope and the Very Large Array with comparable angular resolution. Our spectroscopic observations detected spectral features attributable to polycyclic aromatic hydrocarbons (PAHs) and therefore indicate the presence of a photodissociation region (PDR) around the ionized nebula. This result increases the number of LBVs and LBV candidates where a PDR has been found, confirming the importance of such a component in the total mass-loss budget of the central object during this elusive phase of massive star evolution. We have analyzed and compared the mid-IR and radio maps, and derive several results concerning the associated nebula. There is evidence for grain distribution variations across the nebula, with a predominant contribution from bigger grains in the northern part of the nebula while PAH and smaller grains are more concentrated in the southern part. A compact radio component located where there is a lack of thermal dust grains corroborates the presence of a shock in the southern nebula, which could arise as a consequence of the interaction of a fast outflow with the slower, expanding dusty nebula. Such a shock would be a viable means for PAH production as well as for changes in the grain size distribution. Finally, from the detection of a central radio component probably associated with the wind from the central massive supergiant, we derive a current mass-loss rate of M-dot =(1.46{+-}0.15)x10{sup -6} M{sub sun} yr{sup -1}.

  6. Science case and requirements for the MOSAIC concept for a multi-object spectrograph for the European Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Evans, C. J.; Puech, M.; Barbuy, B.; Bonifacio, P.; Cuby, J.-G.; Guenther, E.; Hammer, F.; Jagourel, P.; Kaper, L.; Morris, S. L.; Afonso, J.; Amram, P.; Aussel, H.; Basden, A.; Bastian, N.; Battaglia, G.; Biller, B.; Bouché, N.; Caffau, E.; Charlot, S.; Clénet, Y.; Combes, F.; Conselice, C.; Contini, T.; Dalton, G.; Davies, B.; Disseau, K.; Dunlop, J.; Fiore, F.; Flores, H.; Fusco, T.; Gadotti, D.; Gallazzi, A.; Giallongo, E.; Gonçalves, T.; Gratadour, D.; Hill, V.; Huertas-Company, M.; Ibata, R.; Larsen, S.; Le Fèvre, O.; Lemasle, B.; Maraston, C.; Mei, S.; Mellier, Y.; Östlin, G.; Paumard, T.; Pello, R.; Pentericci, L.; Petitjean, P.; Roth, M.; Rouan, D.; Schaerer, D.; Telles, E.; Trager, S.; Welikala, N.; Zibetti, S.; Ziegler, B.

    2014-07-01

    Over the past 18 months we have revisited the science requirements for a multi-object spectrograph (MOS) for the European Extremely Large Telescope (E-ELT). These efforts span the full range of E-ELT science and include input from a broad cross-section of astronomers across the ESO partner countries. In this contribution we summarise the key cases relating to studies of high-redshift galaxies, galaxy evolution, and stellar populations, with a more expansive presentation of a new case relating to detection of exoplanets in stellar clusters. A general requirement is the need for two observational modes to best exploit the large (>=40 arcmin2) patrol field of the E-ELT. The first mode (`high multiplex') requires integrated-light (or coarsely resolved) optical/near-IR spectroscopy of >100 objects simultaneously. The second (`high definition'), enabled by wide-field adaptive optics, requires spatially-resolved, near-IR of >10 objects/sub-fields. Within the context of the conceptual study for an ELT-MOS called MOSAIC, we summarise the toplevel requirements from each case and introduce the next steps in the design process.

  7. Reflections on the discovery space for a large ultraviolet-visible telescope: inputs from the European-led EUVO exercise

    NASA Astrophysics Data System (ADS)

    Gómez de Castro, Ana I.; Gaensicke, Boris; Neiner, Coralie; Barstow, Martin A.

    2016-10-01

    The solutions to a number of astrophysical problems require access to the ultraviolet, optical, and infrared from space-based facilities, with capabilities beyond those available with Hubble Space Telescope or James Webb Space Telescope. A large ultraviolet-optical-infrared telescope will need to have a large collecting area and milliarcsecond angular resolution capabilities plus highly efficient instruments, providing a revolutionary enhancement in capability. During 2013, the European astronomical community was involved in an exercise to outline the big science that could be achieved with such a facility; the proposal was called EUVO (as per European Ultraviolet-Visible Observatory). Inspired by that work, we describe a proposal on future science and instrumentation to be carried out with a 10-m class telescope.

  8. Structural Feasibility Analysis of a Robotically Assembled Very Large Aperture Optical Space Telescope

    NASA Technical Reports Server (NTRS)

    Wilkie, William Keats; Williams, R. Brett; Agnes, Gregory S.; Wilcox, Brian H.

    2007-01-01

    This paper presents a feasibility study of robotically constructing a very large aperture optical space telescope on-orbit. Since the largest engineering challenges are likely to reside in the design and assembly of the 150-m diameter primary reflector, this preliminary study focuses on this component. The same technology developed for construction of the primary would then be readily used for the smaller optical structures (secondary, tertiary, etc.). A reasonable set of ground and on-orbit loading scenarios are compiled from the literature and used to define the structural performance requirements and size the primary reflector. A surface precision analysis shows that active adjustment of the primary structure is required in order to meet stringent optical surface requirements. Two potential actuation strategies are discussed along with potential actuation devices at the current state of the art. The finding of this research effort indicate that successful technology development combined with further analysis will likely enable such a telescope to be built in the future.

  9. GESE: A Small UV Space Telescope to Conduct a Large Spectroscopic Survey of Z-1 Galaxies

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Gong, Qian; Hull, Tony; Kruk, Jeffrey; Purves, Lloyd

    2013-01-01

    One of the key goals of NASA's astrophysics program is to answer the question: How did galaxies evolve into the spirals and elliptical galaxies that we see today? We describe a space mission concept called Galaxy Evolution Spectroscopic Explorer (GESE) to address this question by making a large spectroscopic survey of galaxies at a redshift, z is approximately 1 (look-back time of approximately 8 billion years). GESE is a 1.5-meter space telescope with an ultraviolet (UV) multi-object slit spectrograph that can obtain spectra of hundreds of galaxies per exposure. The spectrograph covers the spectral range, 0.2-0.4 micrometers at a spectral resolving power, R approximately 500. This observed spectral range corresponds to 0.1-0.2 micrometers as emitted by a galaxy at a redshift, z=1. The mission concept takes advantage of two new technological advances: (1) light-weighted, wide-field telescope mirrors, and (2) the Next- Generation MicroShutter Array (NG-MSA) to be used as a slit generator in the multi-object slit spectrograph.

  10. Coordinate metrology of a primary surface composite panel from the Large Millimeter Telescope

    NASA Astrophysics Data System (ADS)

    Gale, David M.; Lucero Álvarez, Maribel; Cabrera Cuevas, Lizeth; Leon-Huerta, Andrea; Arizmendi Reyes, Edgar; Icasio Hernández, Octavio; Castro Santos, David; Hernández Ríos, Emilio; Tecuapetla Sosa, Esteban; Tzile Torres, Carlos; Viliesid Alonso, Miguel

    2016-07-01

    The Large Millimeter Telescope (LMT) is a single-dish fully-steerable radio telescope presently operating with a 32.5 m parabolic primary reflector, in the process of extension to 50 m. The project is managed by the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) in México, and the University of Massachusetts Amherst, USA. A laminated surface panel from the LMT primary reflector has been subjected to a surface measurement assay at Mexico's National Metrology Center (CENAM). Data obtained using a coordinate measuring machine and laser tracker owned by CENAM is compared with measurements using an identical model laser tracker and the photogrammetry technique, the latter systems owned and operated by the LMT. All measurements were performed within the controlled metrology environment at CENAM. The measurement exercise is intended to prepare the groundwork for converting this spare surface panel into a calibrated work-piece. The establishment of a calibrated work-piece provides quality assurance for metrology through measurement traceability. It also simplifies the evaluation of measurement uncertainty for coordinate metrology procedures used by the LMT project during reflector surface qualification.

  11. Fermi Large Area Telescope Observations of the Cygnus Loop Supernova Remnant

    SciTech Connect

    Katagiri, H.; Tibaldo, L.; Ballet, J.; Giordano, F.; Grenier, I.A.; Porter, T.A.; Roth, M.; Tibolla, O.; Uchiyama, Y.; Yamazaki, R.; /Sagamihara, Aoyama Gakuin U.

    2011-11-08

    We present an analysis of the gamma-ray measurements by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region of the supernova remnant (SNR) Cygnus Loop (G74.0-8.5). We detect significant gamma-ray emission associated with the SNR in the energy band 0.2-100 GeV. The gamma-ray spectrum shows a break in the range 2-3 GeV. The gamma-ray luminosity is {approx} 1 x 10{sup 33} erg s{sup -1} between 1-100 GeV, much lower than those of other GeV-emitting SNRs. The morphology is best represented by a ring shape, with inner/outer radii 0{sup o}.7 {+-} 0{sup o}.1 and 1{sup o}.6 {+-} 0{sup o}.1. Given the association among X-ray rims, H{alpha} filaments and gamma-ray emission, we argue that gamma rays originate in interactions between particles accelerated in the SNR and interstellar gas or radiation fields adjacent to the shock regions. The decay of neutral pions produced in nucleon-nucleon interactions between accelerated hadrons and interstellar gas provides a reasonable explanation for the gamma-ray spectrum.

  12. The Fermi Large Area Telescope Flare Advocate Program: Rapid Sharing of Results with the Community

    NASA Astrophysics Data System (ADS)

    Thompson, David John; Ciprini, Stefano; Gasparrini, Dario; Fermi Large Area Telescope Collaboration

    2015-01-01

    The Fermi Flare Advocate (also known as Gamma-ray Sky Watcher) program provides a quick look and review of the gamma-ray sky observed daily by the Fermi Large Area Telescope (LAT) through on-duty LAT Flare Advocates and high-level software pipelines like the LAT Automatic Science Processing and the Fermi All-sky Variability Analysis. The FA-GSW service provides rapid alerts and communicates to the external scientific community potentially new gamma-ray sources, interesting transients and flares. News items are regularly posted through the Fermi multiwavelength mailing list, Astronomer's Telegrams and Gamma-ray Coordinates Network notices. A weekly digest containing the highlights about the variable LAT gamma-ray sky at E>100 MeV is published on the web ("Fermi Sky Blog"). From July 2008 to September 2014 more than 290 ATels and 90 GCNs have been published by the Fermi LAT Collaboration. Target of opportunity observing programs with other satellites and telescopes have been triggered by Flare Advocates based on gamma-ray flares from blazars and other kinds of sources.

  13. Lessons from and methods for surveying large areas with the Hubble Space Telescope

    NASA Astrophysics Data System (ADS)

    MacKenty, John W.; Momcheva, Ivelina

    2016-07-01

    Although the imagers on the Hubble Space Telescope only provide fields of view of a few square arc minutes, the telescope has been extensively used to conduct large surveys. These range from relatively shallow mappings in a single filter, multi-filter and multi-epoch surveys, and a series of increasingly deep exposures in several carefully selected fields. HST has also conducted extensive "parallel" surveys either coordinated with a prime instrument (typically using two cameras together) or as "pure" parallel observations to capture images of areas on the sky selected by another science programs (typically spectroscopic observations). Recently, we have tested an approach permitting much faster mapping with the WFC3/IR detector under GYRO pointing control and avoiding the overhead associated with multiple target observations. This results in a four to eight fold increase in mapping speed (at the expense of shallower exposures). This approach enables 250-300 second exposures (reaching H 25th magnitude) covering one square degree in 100 orbits.

  14. The Very Large Telescope Visible Multi-Object Spectrograph Mask Preparation Software

    NASA Astrophysics Data System (ADS)

    Bottini, D.; Garilli, B.; Maccagni, D.; Tresse, L.; Le Brun, V.; Le Fèvre, O.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnaboldi, M.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Cappi, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Guzzo, L.; Ilbert, O.; Iovino, A.; McCracken, H. J.; Marano, B.; Marinoni, C.; Mathez, G.; Mazure, A.; Meneux, B.; Merighi, R.; Paltani, S.; Pollo, A.; Pozzetti, L.; Radovich, M.; Zamorani, G.; Zucca, E.

    2005-09-01

    VIMOS (Visible Multi-Object Spectrograph) is a multiobject imaging spectrograph installed at the VLT (Very large Telescope) at the ESO (European Southern Observatory) Paranal Observatory that is especially suited for survey work. VIMOS is characterized by its very high multiplexing factor: it is possible to take up to 800 spectra with 10" long slits in a single exposure. To fully exploit its multiplexing potential, we designed and implemented a dedicated software tool: the VIMOS Mask Preparation Software (VMMPS), which allows the astronomer to select the objects to be spectroscopically observed, and provides for automatic slit positioning and slit number maximization within the instrumental constraints. The output of VMMPS is used to manufacture the slit masks to be mounted in the instrument for spectroscopic observations.

  15. Strategies for spectroscopy on extremely large telescopes - III. Remapping switched fibre systems

    NASA Astrophysics Data System (ADS)

    Poppett, C. L.; Allington-Smith, J. R.; Murray, G. J.

    2009-10-01

    We explore the use of remapping techniques to improve the efficiency of highly multiplexed fibre systems for astronomical spectroscopy. This is particularly important for the implementation of diverse field spectroscopy (DFS) using highly multiplexed monolithic fibre systems (MFS). DFS allows arbitrary distributions of target regions to be addressed to optimize observing efficiency when observing complex, clumpy structures such as protoclusters which will be increasingly accessible to extremely large telescopes. We show how the adoption of various types of remapping between the input and output of an MFS can allow contiguous regions of spatial elements to be selected using only simple switch arrays. Finally, we show how this compares in efficiency with integral-field and multi-object spectroscopy by simulations using artificial and real catalogues of objects. With the adoption of these mapping strategies, DFS outperforms other techniques when addressing a range of realistic target distributions. These techniques are also applicable to biomedical science and were in fact inspired by it.

  16. Fermi Large Area Telescope observations of high-energy gamma-ray emission from Solar flares

    NASA Astrophysics Data System (ADS)

    Pesce Rollins, Melissa

    2017-01-01

    The Fermi Large Area Telescope (LAT) observations of the active Sun provide the largest sample of detected solar flares with emission greater than 30 MeV to date. These include detections of impulsive and sustained emission, extending up to 20 hours in the case of the 2012 March 7 X-class flares. These high-energy flares are coincident with GOES X-ray flares of X, M and C classes as well as very fast Coronal Mass Ejections (CME). We will present results from the First Fermi-LAT solar flare catalog covering the majority of Solar Cycle 24 including correlation studies with the associated Solar Energetic Particles (SEP) and CMEs.

  17. Software for automated testing and characterization of CCDs for Large Synoptic Survey Telescope (LSST)

    NASA Astrophysics Data System (ADS)

    Prouza, Michael; Kubánek, Petr; O'Connor, Paul; Kotov, Ivan; Frank, James; Antilogus, Pierre

    2010-07-01

    We present the latest modifications of the open source observatory control software package RTS2. New features were developed specifically for the automated testing of CCD chips for the mosaic camera of the Large Synoptic Survey Telescope. Currently, the system is in operation at Brookhaven National Laboratory in Upton, USA and at Laboratoire de Physique Nucĺeaire et des Hautes ´Energies in Paris, France. RTS2 software is currently used to characterize the sensors from various vendors and will be used first for selection and then for testing of production CCD sensors. With our system we are able to automatically obtain a series of images for analysis. Data is used to study many aspects of sensor characteristics, including wavelength dependence of quantum efficiency, the dark current, and the linearity of the CCD response as a function of back-bias voltage and temperature. We also can measure a point spread function over the whole surface of the CCD sensors.

  18. Measurement of Separate Cosmic-Ray Electron and Positron Spectra with the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Brogland, A. W.; Bouvier, A.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Ferrara, E. C.; Harding, A. K.; McEnery, J. E.

    2011-01-01

    We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because the instrument does not have an onboard magnet, we distinguish the two species by exploiting the Earth's shadow, which is offset in opposite directions for opposite charges due to the Earth's magnetic field. We estimate and subtract the cosmic-ray proton background using two different methods that produce consistent results. We report the electron-only spectrum, the positron-only spectrum, and the positron fraction between 20 GeV and 200 GeV, We confirm that the fraction rises with energy in the 20-100 GeV range and determine for the first time that it continues to rise between 100 and 200 GeV,

  19. THE BALLOON-BORNE LARGE APERTURE SUBMILLIMETER TELESCOPE (BLAST) 2006: CALIBRATION AND FLIGHT PERFORMANCE

    SciTech Connect

    Truch, Matthew D. P.; Devlin, Mark J.; Dicker, Simon R.; Klein, Jeff; Ade, Peter A. R.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip; Moncelsi, Lorenzo; Pascale, Enzo; Bock, James J.; Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen; Gundersen, Joshua O.; Hughes, David H.; Martin, Peter G.; Netterfield, C. Barth; Olmi, Luca; Patanchon, Guillaume

    2009-12-20

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) operated successfully during a 250 hr flight over Antarctica in 2006 December (BLAST06). As part of the calibration and pointing procedures, the red hypergiant star VY CMa was observed and used as the primary calibrator. Details of the overall BLAST06 calibration procedure are discussed. The 1sigma uncertainty on the absolute calibration is accurate to 9.5%, 8.7%, and 9.2% at the 250, 350, and 500 mum bands, respectively. The errors are highly correlated between bands resulting in much lower errors for the derived shape of the 250-500 mum continuum. The overall pointing error is < 5'' rms for the 36'', 42'', and 60'' beams. The performance of optics and pointing systems is discussed.

  20. Recent Results on SNRs and PWNe from the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Hays, Elizabeth A.

    2010-01-01

    Topics include: Fermi LAT Collaboration groups; galactic results from LAT; a GeV, wide-field instrument; the 1FGL catalog, the Fermi LAT 1FGL source catalog, unidentified gamma-ray sources; variability in 1FGL sources; curvature in 1FGL sources; spectral-variability classification; gamma-ray pulsars and MSPs; GeV PWN - where to look; Crab pulsar and nebula; Vela X nebular of Vela pulsar; MSH 15-52; GeV PWNe spectra; GeV nebula limits; Nebula search of LAT pulsars; supernova remnants; SNR: GeV morphology; SNR: molecular connection; SNR: GeV breaks; SNR: young vs. old. The summary includes slides about the Large Area Telescope (LAT) and LAT sensitivity with time.

  1. The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) 2005: Calibration and Targeted Sources

    NASA Astrophysics Data System (ADS)

    Truch, Matthew; BLAST Collaboration

    2007-12-01

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) operated successfully during a 100-hour flight from northern Sweden in June 2005 (BLAST05). As part of the calibration and pointing procedures, several compact sources were mapped, including solar system, Galactic, and extragalactic targets, specifically Pallas, CRL 2688, LDN 1014, IRAS 20126+4104, IRAS 21078+5211, IRAS 21307+5049, IRAS 22134+5834, IRAS 23011+6126, K3-50, W 75N, Mrk 231, NGC 4565, and Arp 220 (this last source being our primary calibrator). The BLAST observations of each compact source are described, flux densities and spectral energy distributions are reported, and these are compared with previous measurements at other wavelengths. BLAST was particularly useful for constraining the slope of the submillimeter continuum.

  2. Modeling and validation of polishing tool influence functions for manufacturing segments for an extremely large telescope.

    PubMed

    Li, Hongyu; Walker, David; Yu, Guoyu; Zhang, Wei

    2013-08-10

    We present a simulation technique to predict tool influence functions (TIFs) based on the Precessions polishing process, which is driven by addressing mass fabrication of the European Extremely Large Telescope mirror segments. Precessions polishing requires accurate and predictable TIFs to optimize the multiple process parameters, particularly when sequential polishing runs are performed by different polishing tools. In this paper, the static and dynamic TIFs are simulated based on the Preston equation. The velocity distribution is calculated according to the geometry of the precession motion. The pressure distribution at the polishing spot is calculated by means of finite element analysis (FEA). The FEA result is validated by direct force measurement with a simulation error of 4.3%. The simulation results of TIFs are verified by an experiment that shows the residual errors are less than 5% for both static and dynamic TIFs.

  3. A New Large-area Muon Telescope Detector at Mid-rapidity at RHIC

    NASA Astrophysics Data System (ADS)

    Lin, Guoji; Xu, Zhangbu

    2006-10-01

    μ particle identification at middle and high pT range is crucial for many interesting physics in heavy ion collision experiment, like the dimuon continuum, the quarkonia production, and the Drell-Yan process. Due to the electromagnetic nature of interaction, μ carries information with direct sensitivity to the early stage of the high-energy nuclear collision before chemical freezeout. More importantly, μ is a background free probe compared to electron with no photon conversion background and much less Dalitz decay. A large-area Muon Telescope Detector (MTD) at mid-rapidity at RHIC is proposed and under investigation. In this talk the simulation of μ detection and hadron rejection will be shown. The preliminary result of the first test in run 6 p+p collisions will be discussed. A significant enhancement of high pT charged particles is achieved in this test run. Finally the plans for future upgrade will be presented.

  4. Advanced Technology Large-Aperture Space Telescope: Science Drivers and Technology Developments

    NASA Technical Reports Server (NTRS)

    Postman, Marc; Brown, Tom; Sembach, Kenneth; Glavallsco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Philip; Tumlinson, Jason; Mountain, Matt; Soummer, Remi; Hyde, Tupper

    2012-01-01

    The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8- to 16-m ultraviolet optical near Infrared space observatory for launch in the 2025 to 2030 era. ATLAST will allow astronomers to answer fundamental questions at the forefront of modern astrophysics, including: Is there life elsewhere in the Galaxy? We present a range of science drivers and the resulting performance requirements for ATLAST (8- to 16-marcsec angular resolution, diffraction limited imaging at 0.5 micron wavelength, minimum collecting area of 45 sq m, high sensitivity to light wavelengths from 0.1 to 2.4 micron, high stability in wavefront sensing and control). We also discuss the priorities for technology development needed to enable the construction of ATLAST for a cost that is comparable to that of current generation observatory-class space missions.

  5. The Trigger And Onboard Filter of the GLAST Large Area Telescope

    SciTech Connect

    Hughes, R.; Grove, J.E.; Kocian, M.; Ritz, S.; Russell, J.J.; Siskind, E.; Smith, P.; Winer, B.; Usher, T.; /SLAC

    2007-11-13

    The GLAST Large Area Telescope (LAT) will measure the cosmic gamma-ray flux in the energy range 20 MeV to >300 GeV. The LAT will open a new and important window on a wide variety of high-energy phenomena. Achieving this capability requires a hardware trigger and onboard software event filters that are robust and highly efficient for gamma rays while keeping the event rates due to the much larger fluxes of charged particle backgrounds at an acceptable level. Because of the important discovery windows for science and the uncertainties in the background fluxes, configuration flexibility is a particularly important system feature. This poster describes the purposes and architecture of the system, the components and capabilities of the hardware trigger and onboard software filters, testing and operation experience on the ground, and the on-orbit operations plan and expected performance.

  6. Integration and verification testing of the Large Synoptic Survey Telescope camera

    NASA Astrophysics Data System (ADS)

    Lange, Travis; Bond, Tim; Chiang, James; Gilmore, Kirk; Digel, Seth; Dubois, Richard; Glanzman, Tom; Johnson, Tony; Lopez, Margaux; Newbry, Scott P.; Nordby, Martin E.; Rasmussen, Andrew P.; Reil, Kevin A.; Roodman, Aaron J.

    2016-08-01

    We present an overview of the Integration and Verification Testing activities of the Large Synoptic Survey Telescope (LSST) Camera at the SLAC National Accelerator Lab (SLAC). The LSST Camera, the sole instrument for LSST and under construction now, is comprised of a 3.2 Giga-pixel imager and a three element corrector with a 3.5 degree diameter field of view. LSST Camera Integration and Test will be taking place over the next four years, with final delivery to the LSST observatory anticipated in early 2020. We outline the planning for Integration and Test, describe some of the key verification hardware systems being developed, and identify some of the more complicated assembly/integration activities. Specific details of integration and verification hardware systems will be discussed, highlighting some of the technical challenges anticipated.

  7. Structural evaluation of candidate designs for the large space telescope primary mirror

    NASA Technical Reports Server (NTRS)

    Soosaar, K.; Grin, R.; Furey, M.; Hamilton, J.

    1975-01-01

    Structural performance analyses were conducted on two candidate designs (Itek and Perkin-Elmer designs) for the large space telescope three-meter mirror. The mirror designs and the finite-element models used in the analyses evaluation are described. The results of the structural analyses for several different types of loading are presented in tabular and graphic forms. Several additional analyses are also reported: the evaluation of a mirror design concept proposed by the Boeing Co., a study of the global effects of local cell plate deflections, and an investigation of the fracture mechanics problems likely to occur with Cervit and ULE. Flexibility matrices were obtained for the Itek and Perkin-Elmer mirrors to be used in active figure control studies. Summary, conclusions, and recommendations are included.

  8. Measurement of Separate Cosmic-Ray Electron and Positron Spectra with the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Ferrara, E. C.; Harding, A. K.; McEnery, J. E.; Moiseev, A. A.; Ackemann, M.

    2012-01-01

    We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because the instrument does not have an onboard magnet, we distinguish the two species by exploiting Earth's shadow, which, is offset in opposite directions for opposite charges due to Earth's magnetic field. We estimate and subtract the cosmic-ray proton background using two different methods that produce consistent results. We report the electron-only spectrum, the positron-only spectrum, and the positron fraction between 20 and 200 Ge V. We confirm that the fraction rises with energy in the 20-100 Ge V range. The three new spectral points between 100 and 200 GeV are consistent with a fraction that is continuing to rise with energy.

  9. Infrared photometry with 'wall-eyed' pointing at the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Spalding, Eckhart; Skemer, Andrew; Hinz, Philip M.; Hill, John M.

    2016-08-01

    The brightness and variability of the atmosphere in the thermal infrared poses obstacles to precision photometry measurements. The need to remove atmospheric effects calls for the use of a comparison star, but it is usually impossible to fit both science and comparison targets on current long-wavelength (>2 μm) detectors. We present a new pointing mode at the Large Binocular Telescope, which has twin 8.4-m primary mirrors that can be pointed up to 2 arcminutes apart and allow the placement of both targets on a small-field infrared detector. We present an observation of the primary transit of an exoplanet in front of its host star, and use it to provide preliminary constraints on the attainable photometric precision.

  10. Adaptive neuro-control for large flexible structures

    NASA Astrophysics Data System (ADS)

    Krishna Kumar, K.; Montgomery, L.

    1992-12-01

    Special problems related to control system design for large flexible structures include the inherent low damping, wide range of modal frequencies, unmodeled dynamics, and possibility of system failures. Neuro-control, which combines concepts from artificial neural networks and adaptive control is investigated as a solution to some of these problems. Specifically, the roles of neutro-controllers in learning unmodeled dynamics and adaptive control for system failures are investigated. The neuro-controller synthesis procedure and its capabilities in adaptively controlling the structure are demonstrated using a mathematical model of an existing structure, the advanced control evaluation for systems test article located at NASA/Marshall Space Flight Center. Also, the real-time adaptive capability of neuro-controllers is demonstrated via an experiment utilizing a flexible clamped-free beam equipped with an actuator that uses a bang-bang controller.

  11. Topology optimization-based lightweight primary mirror design of a large-aperture space telescope.

    PubMed

    Liu, Shutian; Hu, Rui; Li, Quhao; Zhou, Ping; Dong, Zhigang; Kang, Renke

    2014-12-10

    For the large-aperture space telescope, the lightweight primary mirror design with a high-quality optical surface is a critical and challenging issue. This work presents a topology optimization-based design procedure for a lightweight primary mirror and a new mirror configuration of a large-aperture space telescope is obtained through the presented design procedure. Inspired by the topology optimization method considering cast constraints, an optimization model for the configuration design of the mirror back is proposed, through which the distribution and the heights of the stiffeners on the mirror back can be optimized simultaneously. For the purpose of minimizing the optical surface deviation due to self-weight and polishing pressure loadings, the objective function is selected as to maximize the mirror structural stiffness, which can be achieved by minimizing the structural compliance. The total mass of the primary mirror is assigned as the constraint. In the application example, results of the optimized design topology for two kinds of mass constraints are presented. Executing the design procedure for specific requirements and postprocessing the topology obtained of the structure, a new mirror configuration with tree-like stiffeners and a multiple-arch back in double directions is proposed. A verification model is constructed to evaluate the design results and the finite element method is used to calculate the displacement of the mirror surface. Then the RMS deviation can be obtained after fitting the deformed surface by Zernike polynomials. The proposed mirror is compared with two classical mirrors in the optical performance, and the comparison results demonstrate the superiority of the new mirror configuration.

  12. The next generation balloon-borne large aperture submillimeter telescope (BLAST-TNG)

    NASA Astrophysics Data System (ADS)

    Dober, Bradley Jerald

    Large areas of astrophysics, such as precision cosmology, have benefited greatly from large maps and datasets, yielded by telescopes of ever-increasing number and ability. However, due to the unique challenges posed by submillimeter polarimetry, the study of molecular cloud dynamics and star formation remain stunted. Previously, polarimetry data was limited to a few vectors on only the brightest areas of molecular clouds. This made drawing statistically-driven conclusions a daunting task. However, the successful flight of the Balloon-born Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) generated maps with thousands of independent polarization measurements of molecular clouds, and ushered in a new era of empirical modeling of molecular cloud dynamics. Now that the potential benefits from large-scale maps of magnetic fields in molecular clouds had been identified, a successor that would truly unlock the secrets must be born. The Next Generation Balloon-borne Large Aperture Submillimeter Telescope (BLAST-TNG), the successor to BLASTPol, has the ability to make larger and more detailed maps of magnetic fields in molecular clouds. It will push the field of star formation into a statistics-driven, empirical realm. With these large, detailed datasets, astronomers will be able to find new relationships between the dust dynamics and the magnetic fields. The field will surge to a new level of understanding. One of the key enabling technologies of BLAST-TNG is its three arrays of polarization-sensitive Microwave Kinetic Inductance Detectors (MKIDs). MKIDs are superconducting RLC circuits with a resonant frequency that shifts proportionally to the amount of incident radiation. The key feature of MKIDs is that thousands of detectors, each with their own unique resonant frequency, can be coupled to the same readout line. This technology will be able to drive the production of large-scale monolithic arrays, containing tens or hundreds of thousands of detectors

  13. Residual mode filters and adaptive control in large space structures

    NASA Technical Reports Server (NTRS)

    Davidson, Roger A.; Balas, Mark J.

    1989-01-01

    One of the most difficult problems in controlling large systems and structures is compensating for the destructive interaction which can occur between the reduced-order model (ROM) of the plant, which is used by the controller, and the unmodeled dynamics of the plant, often called the residual modes. The problem is more significant in the case of large space structures because their naturally light damping and high performance requirements lead to more frequent, destructive residual mode interaction (RMI). Using the design/compensation technique of residual mode filters (RMF's), effective compensation of RMI can be accomplished in a straightforward manner when using linear controllers. The use of RMF's has been shown to be effective for a variety of large structures, including a space-based laser and infinite dimensional systems. However, the dynamics of space structures is often uncertain and may even change over time due to on-orbit erosion from space debris and corrosive chemicals in the upper atmosphere. In this case, adaptive control can be extremely beneficial in meeting the performance requirements of the structure. Adaptive control for large structures is also based on ROM's and so destructive RMI may occur. Unfortunately, adaptive control is inherently nonlinear, and therefore the known results of RMF's cannot be applied. The purpose is to present the results of new research showing the effects of RMI when using adaptive control and the work which will hopefully lead to RMF compensation of this problem.

  14. Hybrid Electrostatic/Flextensional Mirror for Lightweight, Large-Aperture, and Cryogenic Space Telescopes

    NASA Technical Reports Server (NTRS)

    Patrick, Brian; Moore, James; Hackenberger, Wesley; Jiang, Xiaoning

    2013-01-01

    A lightweight, cryogenically capable, scalable, deformable mirror has been developed for space telescopes. This innovation makes use of polymer-based membrane mirror technology to enable large-aperture mirrors that can be easily launched and deployed. The key component of this innovation is a lightweight, large-stroke, cryogenic actuator array that combines the high degree of mirror figure control needed with a large actuator influence function. The latter aspect of the innovation allows membrane mirror figure correction with a relatively low actuator density, preserving the lightweight attributes of the system. The principal components of this technology are lightweight, low-profile, high-stroke, cryogenic-capable piezoelectric actuators based on PMN-PT (piezoelectric lead magnesium niobate-lead titanate) single-crystal configured in a flextensional actuator format; high-quality, low-thermal-expansion polymer membrane mirror materials developed by NeXolve; and electrostatic coupling between the membrane mirror and the piezoelectric actuator assembly to minimize problems such as actuator print-through.

  15. The Large Synoptic Survey Telescope and Foundations for Data Exploitation of Petabyte Data Sets

    SciTech Connect

    Cook, K H; Nikolaev, S; Huber, M E

    2007-02-26

    The next generation of imaging surveys in astronomy, such as the Large Synoptic Survey Telescope (LSST), will require multigigapixel cameras that can process enormous amounts of data read out every few seconds. This huge increase in data throughput (compared to megapixel cameras and minute- to hour-long integrations of today's instruments) calls for a new paradigm for extracting the knowledge content. We have developed foundations for this new approach. In this project, we have studied the necessary processes for extracting information from large time-domain databases systematics. In the process, we have produced significant scientific breakthroughs by developing new methods to probe both the elusive time and spatial variations in astrophysics data sets from the SuperMACHO (Massive Compact Halo Objects) survey, the Lowell Observatory Near-Earth Object Search (LONEOS), and the Taiwanese American Occultation Survey (TAOS). This project continues to contribute to the development of the scientific foundations for future wide-field, time-domain surveys. Our algorithm and pipeline development has provided the building blocks for the development of the LSST science software system. Our database design and performance measures have helped to size and constrain LSST database design. LLNL made significant contributions to the foundations of the LSST, which has applications for large-scale imaging and data-mining activities at LLNL. These developments are being actively applied to the previously mentioned surveys producing important scientific results that have been released to the scientific community and more continue to be published and referenced, enhancing LLNL's scientific stature.

  16. Limited list for the objects - candidates for SETI-monitoring with large telescopes

    NASA Astrophysics Data System (ADS)

    Panov, Alexander; Filippova, Lilia; Rudnitskii, Georgiii

    There are about one million stars within one thousand light years region around the Sun that may have habitable planets and which are interesting from the point of view of the SETI problem. All these stars are acceptable in principle for monitoring with large radio telescopes with aim to catch a radio message from aliens but it is still impossible to monitor all of them due to a lack of special instruments designed for SETI like large antenna arrays. In this situation we propose a special limited list of especially interesting objects to monitor with using of usual large radio telescopes in accompanying mode together with usual astrophysical observations. This list consists of the objects of three types and there are only about three dozen objects in total in the list. The first type of objects is represented by sunlike stars satisfying the following criteria: 1) The spectral type is from F8V to K0V; 2) The estimate of the age of the star is from 4 to 6 billions of years; 3) The distance from the Sun is less than 100 light years; 4) The radial velocity is less than 50 km/sec; 5) If it is known the star to have planets, then the eccentricity of orbits is less than 0.2. The special interest among the sunlike stars satisfying the criteria 1-5 are the near-ecliptic ones, since the Earth is seen from them as a transit planet, therefore the solar system may be a preferable target to send a message for aliens from planets of such stars. The second type of objects is a number of stars that are targets of already sent space messages and at the same time which are sunlike stars satisfying the criteria 1-5. Moreover some slow narrow-band radio signal above background was observed previously from one of the second type object and the result should be verified. The objects of the third class are not stars, but they are globular clusters. We elaborate a number of criteria to select globular clusters but emphasize a high level of metallicity. Many stars in such globular clusters

  17. Stellar Dynamics at the Galactic Center with an Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Weinberg, Nevin N.; Milosavljević, Miloš; Ghez, Andrea M.

    2005-04-01

    We discuss physical experiments achievable via the monitoring of stellar dynamics near the massive black hole at the Galactic center with a diffraction-limited, next-generation, extremely large telescope (ELT). Given the likely observational capabilities of an ELT and what is currently known about the stellar environment at the Galactic center, we synthesize plausible samples of stellar orbits around the black hole. We use the Markov Chain Monte Carlo method to evaluate the constraints that the monitoring of these orbits will place on the matter content within the dynamical sphere of influence of the black hole. We express our results as functions of the number N of stars with detectable orbital motions and the astrometric precision δθ and spectroscopic precision δv at which the stellar proper motions and radial velocities are monitored. Our results are easily scaled to different telescope sizes and precisions. For N=100, δθ=0.5mas, and δv=10kms-1 (a conservative estimate of the capabilities of a 30 m telescope) we find that if the extended matter distribution enclosed by the orbits at 0.01 pc has a mass greater than ~103 Msolar, it will produce measurable deviations from Keplerian motion. Thus, if the concentration of dark matter at the Galactic center matches theoretical predictions, its influence on the orbits will be detectable. We also estimate the constraints that will be placed on the mass of the black hole and on the distance to the Galactic center and find that both will be measured to better than ~0.1%. We discuss the significance of knowing the distance to within a few parsecs and the importance of this parameter for understanding the structure of the Galaxy. We demonstrate that the lowest order relativistic effects, such as the prograde precession, will be detectable if δθ<~0.5mas. Barring the favorable discovery of a star on a highly compact, eccentric orbit, the higher order effects, including the frame dragging due to the spin of the black

  18. Sensitivity projections for dark matter dearches with the Fermi large area telescope

    DOE PAGES

    Charles, E.; M. Sanchez-Conde; Anderson, B.; ...

    2016-05-20

    The nature of dark matter is a longstanding enigma of physics; it may consist of particles beyond the Standard Model that are still elusive to experiments. Among indirect search techniques, which look for stable products from the annihilation or decay of dark matter particles, or from axions coupling to high-energy photons, observations of themore » $$\\gamma$$-ray sky have come to prominence over the last few years, because of the excellent sensitivity of the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope mission. The LAT energy range from 20 MeV to above 300 GeV is particularly well suited for searching for products of the interactions of dark matter particles. In this report we describe methods used to search for evidence of dark matter with the LAT, and review the status of searches performed with up to six years of LAT data. We also discuss the factors that determine the sensitivities of these searches, including the magnitudes of the signals and the relevant backgrounds, considering both statistical and systematic uncertainties. We project the expected sensitivities of each search method for 10 and 15 years of LAT data taking. In particular, we find that the sensitivity of searches targeting dwarf galaxies, which provide the best limits currently, will improve faster than the square root of observing time. Current LAT limits for dwarf galaxies using six years of data reach the thermal relic level for masses up to 120 GeV for the $$b\\bar{b}$$ annihilation channel for reasonable dark matter density profiles. With projected discoveries of additional dwarfs, these limits could extend to about 250 GeV. With as much as 15 years of LAT data these searches would be sensitive to dark matter annihilations at the thermal relic cross section for masses to greater than 400 GeV (200 GeV) in the $$b\\bar{b}$$ ($$\\tau^+ \\tau^-$$) annihilation channels.« less

  19. Thermal Analysis of the Advanced Technology Large Aperture Space Telescope (ATLAST) 8 Meter Primary Mirror

    NASA Technical Reports Server (NTRS)

    Hornsby, Linda; Stahl, H. Philip; Hopkins, Randall C.

    2010-01-01

    The Advanced Technology Large Aperture Space Telescope (ATLAST) preliminary design concept consists of an 8 meter diameter monolithic primary mirror enclosed in an insulated, optical tube with stray light baffles and a sunshade. ATLAST will be placed in orbit about the Sun-Earth L2 and will experience constant exposure to the sun. The insulation on the optical tube and sunshade serve to cold bias the telescope which helps to minimize thermal gradients. The primary mirror will be maintained at 280K with an active thermal control system. The geometric model of the primary mirror, optical tube, sun baffles, and sunshade was developed using Thermal Desktop(R) SINDA/FLUINT(R) was used for the thermal analysis and the radiation environment was analyzed using RADCAD(R). A XX node model was executed in order to characterize the static performance and thermal stability of the mirror during maneuvers. This is important because long exposure observations, such as extra-solar terrestrial planet finding and characterization, require a very stable observatory wave front. Steady state thermal analyses served to predict mirror temperatures for several different sun angles. Transient analyses were performed in order to predict thermal time constant of the primary mirror for a 20 degree slew or 30 degree roll maneuver. This paper describes the thermal model and provides details of the geometry, thermo-optical properties, and the environment which influences the thermal performance. All assumptions that were used in the analysis are also documented. Parametric analyses are summarized for design parameters including primary mirror coatings and sunshade configuration. Estimates of mirror heater power requirements are reported. The thermal model demonstrates results for the primary mirror heated from the back side and edges using a heater system with multiple independently controlled zones.

  20. Sensitivity projections for dark matter dearches with the Fermi large area telescope

    SciTech Connect

    Charles, E.; M. Sanchez-Conde; Anderson, B.; Caputo, R.; Cuoco, A.; Di Mauro, M.; Drlica-Wagner, A.; Gomez-Vargas, G. A.; Meyer, M.; Tibaldo, L.; Wood, M.; Zaharijas, G.; Zimmer, S.; Ajello, M.; Albert, A.; Baldini, L.; Bechtol, K.; Bloom, E. D.; Ceraudo, F.; Cohen-Tanugi, J.; Gaskins, J.; Gustafsson, M.; Mirabal, N.; Razzano, M.

    2016-05-20

    The nature of dark matter is a longstanding enigma of physics; it may consist of particles beyond the Standard Model that are still elusive to experiments. Among indirect search techniques, which look for stable products from the annihilation or decay of dark matter particles, or from axions coupling to high-energy photons, observations of the $\\gamma$-ray sky have come to prominence over the last few years, because of the excellent sensitivity of the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope mission. The LAT energy range from 20 MeV to above 300 GeV is particularly well suited for searching for products of the interactions of dark matter particles. In this report we describe methods used to search for evidence of dark matter with the LAT, and review the status of searches performed with up to six years of LAT data. We also discuss the factors that determine the sensitivities of these searches, including the magnitudes of the signals and the relevant backgrounds, considering both statistical and systematic uncertainties. We project the expected sensitivities of each search method for 10 and 15 years of LAT data taking. In particular, we find that the sensitivity of searches targeting dwarf galaxies, which provide the best limits currently, will improve faster than the square root of observing time. Current LAT limits for dwarf galaxies using six years of data reach the thermal relic level for masses up to 120 GeV for the $b\\bar{b}$ annihilation channel for reasonable dark matter density profiles. With projected discoveries of additional dwarfs, these limits could extend to about 250 GeV. With as much as 15 years of LAT data these searches would be sensitive to dark matter annihilations at the thermal relic cross section for masses to greater than 400 GeV (200 GeV) in the $b\\bar{b}$ ($\\tau^+ \\tau^-$) annihilation channels.

  1. Gamma-Ray Observations of the Orion Molecular Clouds with the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Allafort, A.; Antolini, E.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Ferrara, E. C.; Harding, A. K.; Troja, E.

    2012-01-01

    We report on the gamma-ray observations of giant molecular clouds Orion A and B with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The gamma-ray emission in the energy band between approx 100 MeV and approx 100 GeV is predicted to trace the gas mass distribution in the clouds through nuclear interactions between the Galactic cosmic rays (CRs) and interstellar gas. The gamma-ray production cross-section for the nuclear interaction is known to approx 10% precision which makes the LAT a powerful tool to measure the gas mass column density distribution of molecular clouds for a known CR intensity. We present here such distributions for Orion A and B, and correlate them with those of the velocity-integrated CO intensity (W(sub CO)) at a 1 deg 1 deg pixel level. The correlation is found to be linear over a W(sub CO) range of approx 10-fold when divided in three regions, suggesting penetration of nuclear CRs to most of the cloud volumes. The W(sub CO)-to-mass conversion factor, X(sub CO), is found to be approx 2.3 10(exp 20) / sq cm (K km/s)(exp -1) for the high-longitude part of Orion A (l > 212 deg), approx 1.7 times higher than approx 1.3 10(exp 20) found for the rest of Orion A and B. We interpret the apparent high X(sub CO) in the high-longitude region of Orion A in the light of recent works proposing a nonlinear relation between H2 and CO densities in the diffuse molecular gas.W(sub CO) decreases faster than the H2 column density in the region making the gas "darker" to W(sub CO).

  2. Electromagnetic counterparts to Gravitational Wave events with the Fermi Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Vianello, Giacomo; Omodei, Nicola; Racusin, Judith L.; McEnery, Julie E.; Chiang, James; Buson, Sara; Fermi LAT Collaboration

    2017-01-01

    At least a fraction of Gravitational Wave (GW) progenitors is expected to emit an electromagnetic (EM) signal in the form of a short gamma-ray burst (sGRB). The discovery of such a transient EM counterpart is challenging because the LIGO/VIRGO localization region is much larger (several hundreds of square degrees) than the field of view of X-ray, optical and radio telescopes. The Fermi Large Area Telescope (LAT) has a wide field of view (~ 2.4 sr), and detects ~2-3 sGRBs per year above 100 MeV. It can detect them not only during the short prompt phase but also during their long-lasting high-energy afterglow phase. If other wide-field high-energy instruments such as Fermi-GBM, Swift-BAT or INTEGRAL-ISGRI cannot detect or localize with enough precision an EM counterpart during the prompt phase, the LAT can potentially pinpoint it with < 10 arcmin accuracy during the afterglow phase. This routinely happens in the case of gamma-ray bursts. Moreover, the LAT covers the entire localization region within hours of any GW triggers during normal operations, allowing upper bounds to be evaluated. This has been demonstrated in the case of the three known GW events (GW150914, LVT151012, and GW151226). Over the coming years, as LIGO and Virgo approach design sensitivity and will soon be able to detect these mergers, LAT will continue to provide a unique capability to potentially localize and characterize gravitational wave events.

  3. Optical performance assessment under environmental and mechanical perturbations in large, deployable telescopes

    NASA Astrophysics Data System (ADS)

    Folley, Christopher; Bronowicki, Allen

    2005-09-01

    Prediction of optical performance for large, deployable telescopes under environmental conditions and mechanical disturbances is a crucial part of the design verification process of such instruments for all phases of design and operation: ground testing, commissioning, and on-orbit operation. A Structural-Thermal-Optical-Performance (STOP) analysis methodology is often created that integrates the output of one analysis with the input of another. The integration of thermal environment predictions with structural models is relatively well understood, while the integration of structural deformation results into optical analysis/design software is less straightforward. A Matlab toolbox has been created that effectively integrates the predictions of mechanical deformations on optical elements generated by, for example, finite element analysis, and computes optical path differences for the distorted prescription. The engine of the toolbox is the real ray-tracing algorithm that allows the optical surfaces to be defined in a single, global coordinate system thereby allowing automatic alignment of the mechanical coordinate system with the optical coordinate system. Therefore, the physical location of the optical surfaces is identical in the optical prescription and the finite element model. The application of rigid body displacements to optical surfaces, however, is more general than for use solely in STOP analysis, such as the analysis of misalignments during the commissioning process. Furthermore, all the functionality of Matlab is available for optimization and control. Since this is a new tool for use on flight programs, it has been verified against CODE V. The toolbox' functionality, to date, is described, verification results are presented, and, as an example of its utility, results of a thermal distortion analysis are presented using the James Webb Space Telescope (JWST) prescription.

  4. A large aperture balloon-borne telescope for a submillimeter wavelength survey of the galactic plane

    NASA Technical Reports Server (NTRS)

    Silverberg, R. F.; Hauser, M. G.; Walser, D. W.; Flanick, A.; Silver, A. D.; Smith, J.; Gezari, D. Y.; Kelsall, T.; Cheung, L. H.; Skillman, T. L., Jr.

    1983-01-01

    A balloon-borne, 1.2 meter Cassegrain telescope with a servo-controlled chopping secondary mirror has been developed and used to survey the Galactic Plane at submillimeter wavelengths. The telescope pointing system uses a gyroscope as the primary stabilization reference and makes use of microprocessors for pointing control, on-board data collection, and telemetry formatting. A description of the telescope, multi-channel liquid-helium-cooled focal plane and the aspect and orientation subsystems are presented.

  5. High-Resolution Hα Velocity Fields of Nearby Spiral Galaxies with the Southern African Large Telescope

    NASA Astrophysics Data System (ADS)

    Mitchell, Carl; Williams, Ted; Spekkens, Kristine; Lee-Waddell, Karen; Kuzio de Naray, Rachel; Sellwood, Jerry

    2016-01-01

    In an effort to test ΛCDM predictions of galaxy mass distributions, we have obtained spectrophotometric observations of several nearby spiral galaxies with the Southern African Large Telescope (SALT) Fabry-Pérot (FP) interferometer as part of the RSS Imaging spectroscopy Nearby Galaxy Survey. Utilizing the SALT FP's 8 arcmin field of view and 2 arcsec angular resolution, we have derived 2D velocity fields of the Hα emission line to high spatial resolution at large radii. We have modeled these velocity fields with the DiskFit software package and found them to be in good agreement with lower-resolution velocity fields of the HI 21 cm line for the same galaxies. Here we present our Hα kinematic map of the barred spiral galaxy NGC 578. At the distance to this galaxy (22 Mpc), our kinematic data has a spatial resolution of 185 pc and extends to galactocentric radii of 13 kpc. The high spatial resolution of this data allows us to resolve the inner rising part of the rotation curves, which is compromised by beam smearing in lower-resolution observations. We are using these Hα kinematic data, combined with HI 21 cm kinematics and broadband photometric observations, to place constraints on NGC 578's mass distribution.

  6. Mapping the Large Millimeter Telescope primary reflector using photogrammetry: a first comparison with 12 GHz holography

    NASA Astrophysics Data System (ADS)

    Gale, David M.; Leon-Huerta, Andrea; Cabrera Cuevas, Lizeth; Castro Santos, David; Hernández Ríos, Emilio; Lucero Álvarez, Maribel; Tecuapetla Sosa, Esteban; Tzile Torres, Carlos; Sánchez-Argüelles, David; Narayanan, Gopal; Schloerb, F. Peter; Wilson, Grant W.; Smith, David R.

    2016-07-01

    The Large Millimeter Telescope (LMT) makes extensive use of 12 GHz holography during maintenance periods to finetune the alignment of primary reflector segments to the best-fit design parabola. Tracker measurements have also been used for this task, however the technique is severely limited by environmental noise and large data collection times, on the order of many hours for a single map. In 2015 we started photogrammetry trials as a complimentary measurement technique. Photogrammetry can offer reduced mapping times compared with laser trackers, and like holography, allows maps to be made at arbitrary elevation angles. Depending on the placement of reflecting targets, the technique can also provide higher spatial resolution than currently achieved using our holography system. Accurate photogrammetry requires a robust strategy for the incorporation of multiple camera stations, a task complicated by the size of the antenna, obstructions of the surface by the sub-reflector and tetrapod legs, and the practicability of using the site tower crane as a moving camera platform. Image scaling is also a major consideration, since photogrammetry lacks any inherent distance reference. Therefore appropriate scale bars must be fabricated and located within the camera field of view. Additional considerations relate to the size and placement of reflective targets, and the optimization of camera settings. In this paper we present some initial comparisons of laser tracker, holography and photogrammetry measurements taken in 2015, showing clearly the status of alignment for distinct zones of the currently operating 32.5 m primary collecting area.

  7. Design of a 2-mm Wavelength KIDs Prototype Camera for the Large Millimeter Telescope

    NASA Astrophysics Data System (ADS)

    Velázquez, M.; Ferrusca, D.; Castillo-Dominguez, E.; Ibarra-Medel, E.; Ventura, S.; Gómez-Rivera, V.; Hughes, D.; Aretxaga, I.; Grant, W.; Doyle, S.; Mauskopf, P.

    2016-08-01

    A new camera is being developed for the Large Millimeter Telescope (Sierra Negra, México) by an international collaboration with the University of Massachusetts, the University of Cardiff, and Arizona State University. The camera is based on kinetic inductance detectors (KIDs), a very promising technology due to their sensitivity and especially, their compatibility with frequency domain multiplexing at microwave frequencies allowing large format arrays, in comparison with other detection technologies for mm-wavelength astronomy. The instrument will have a 100 pixels array of KIDs to image the 2-mm wavelength band and is designed for closed cycle operation using a pulse tube cryocooler along with a three-stage sub-kelvin 3He cooler to provide a 250 mK detector stage. RF cabling is used to readout the detectors from room temperature to 250 mK focal plane, and the amplification stage is achieved with a low-noise amplifier operating at 4 K. The readout electronics will be based on open-source reconfigurable open architecture computing hardware in order to perform real-time microwave transmission measurements and monitoring the resonance frequency of each detector, as well as the detection process.

  8. The second fermi large area telescope catalog of gamma-ray pulsars

    SciTech Connect

    Abdo, A. A.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Belfiore, A.; Bellazzini, R.; Bhattacharyya, B.; Bissaldi, E.; Bloom, E. D.; Bonamente, E.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Burgay, M.; Burnett, T. H.; Busetto, G.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Camilo, F.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chaty, S.; Chaves, R. C. G.; Chekhtman, A.; Chen, A. W.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cognard, I.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; DeCesar, M. E.; De Luca, A.; den Hartog, P. R.; de Palma, F.; Dermer, C. D.; Desvignes, G.; Digel, S. W.; Di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Dumora, D.; Espinoza, C. M.; Falletti, L.; Favuzzi, C.; Ferrara, E. C.; Focke, W. B.; Franckowiak, A.; Freire, P. C. C.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gotthelf, E. V.; Grenier, I. A.; Grondin, M. -H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.; Hessels, J.; Hewitt, J.; Hill, A. B.; Horan, D.; Hou, X.; Hughes, R. E.; Jackson, M. S.; Janssen, G. H.; Jogler, T.; Jóhannesson, G.; Johnson, R. P.; Johnson, A. S.; Johnson, T. J.; Johnson, W. N.; Johnston, S.; Kamae, T.; Kataoka, J.; Keith, M.; Kerr, M.; Knödlseder, J.; Kramer, M.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Lyne, A. G.; Manchester, R. N.; Marelli, M.; Massaro, F.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; McLaughlin, M. A.; Mehault, J.; Michelson, P. F.; Mignani, R. P.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nemmen, R.; Nuss, E.; Ohno, M.; Ohsugi, T.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Parent, D.; Perkins, J. S.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato, G.; Pletsch, H. J.; Porter, T. A.; Possenti, A.; Rainò, S.; Rando, R.; Ransom, S. M.; Ray, P. S.; Razzano, M.; Rea, N.; Reimer, A.; Reimer, O.; Renault, N.; Reposeur, T.; Ritz, S.; Romani, R. W.; Roth, M.; Rousseau, R.; Roy, J.; Ruan, J.; Sartori, A.; Saz Parkinson, P. M.; Scargle, J. D.; Schulz, A.; Sgrò, C.; Shannon, R.; Siskind, E. J.; Smith, D. A.; Spandre, G.; Spinelli, P.; Stappers, B. W.; Strong, A. W.; Suson, D. J.; Takahashi, H.; Thayer, J. G.; Thayer, J. B.; Theureau, G.; Thompson, D. J.; Thorsett, S. E.; Tibaldo, L.; Tibolla, O.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Venter, C.; Vianello, G.; Vitale, V.; Wang, N.; Weltevrede, P.; Winer, B. L.; Wolff, M. T.; Wood, D. L.; Wood, K. S.; Wood, M.; Yang, Z.

    2013-09-19

    This catalog summarizes 117 high-confidence ≥0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.

  9. Observing two dark accelerators around the Galactic Centre with Fermi Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Hui, C. Y.; Yeung, P. K. H.; Ng, C. W.; Lin, L. C. C.; Tam, P. H. T.; Cheng, K. S.; Kong, A. K. H.; Chernyshov, D. O.; Dogiel, V. A.

    2016-04-01

    We report the results from a detailed γ-ray investigation in the field of two `dark accelerators', HESS J1745-303 and HESS J1741-302, with 6.9 yr of data obtained by the Fermi Large Area Telescope. For HESS J1745-303, we found that its MeV-GeV emission is mainly originated from the `Region A' of the TeV feature. Its γ-ray spectrum can be modelled with a single power law with a photon index of Γ ˜ 2.5 from few hundreds MeV-TeV. Moreover, an elongated feature, which extends from `Region A' towards north-west for ˜1.3°, is discovered for the first time. The orientation of this feature is similar to that of a large-scale atomic/molecular gas distribution. For HESS J1741-302, our analysis does not yield any MeV-GeV counterpart for this unidentified TeV source. On the other hand, we have detected a new point source, Fermi J1740.1-3013, serendipitously. Its spectrum is apparently curved which resembles that of a γ-ray pulsar. This makes it possibly associated with PSR B1737-20 or PSR J1739-3023.

  10. The Second Fermi Large Area Telescope Catalog of Gamma-Ray Pulsars

    NASA Astrophysics Data System (ADS)

    Abdo, A. A.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Belfiore, A.; Bellazzini, R.; Bhattacharyya, B.; Bissaldi, E.; Bloom, E. D.; Bonamente, E.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Burgay, M.; Burnett, T. H.; Busetto, G.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Camilo, F.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chaty, S.; Chaves, R. C. G.; Chekhtman, A.; Chen, A. W.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cognard, I.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; DeCesar, M. E.; De Luca, A.; den Hartog, P. R.; de Palma, F.; Dermer, C. D.; Desvignes, G.; Digel, S. W.; Di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Dumora, D.; Espinoza, C. M.; Falletti, L.; Favuzzi, C.; Ferrara, E. C.; Focke, W. B.; Franckowiak, A.; Freire, P. C. C.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gotthelf, E. V.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.; Hessels, J.; Hewitt, J.; Hill, A. B.; Horan, D.; Hou, X.; Hughes, R. E.; Jackson, M. S.; Janssen, G. H.; Jogler, T.; Jóhannesson, G.; Johnson, R. P.; Johnson, A. S.; Johnson, T. J.; Johnson, W. N.; Johnston, S.; Kamae, T.; Kataoka, J.; Keith, M.; Kerr, M.; Knödlseder, J.; Kramer, M.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Lyne, A. G.; Manchester, R. N.; Marelli, M.; Massaro, F.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; McLaughlin, M. A.; Mehault, J.; Michelson, P. F.; Mignani, R. P.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nemmen, R.; Nuss, E.; Ohno, M.; Ohsugi, T.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Parent, D.; Perkins, J. S.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato, G.; Pletsch, H. J.; Porter, T. A.; Possenti, A.; Rainò, S.; Rando, R.; Ransom, S. M.; Ray, P. S.; Razzano, M.; Rea, N.; Reimer, A.; Reimer, O.; Renault, N.; Reposeur, T.; Ritz, S.; Romani, R. W.; Roth, M.; Rousseau, R.; Roy, J.; Ruan, J.; Sartori, A.; Saz Parkinson, P. M.; Scargle, J. D.; Schulz, A.; Sgrò, C.; Shannon, R.; Siskind, E. J.; Smith, D. A.; Spandre, G.; Spinelli, P.; Stappers, B. W.; Strong, A. W.; Suson, D. J.; Takahashi, H.; Thayer, J. G.; Thayer, J. B.; Theureau, G.; Thompson, D. J.; Thorsett, S. E.; Tibaldo, L.; Tibolla, O.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Venter, C.; Vianello, G.; Vitale, V.; Wang, N.; Weltevrede, P.; Winer, B. L.; Wolff, M. T.; Wood, D. L.; Wood, K. S.; Wood, M.; Yang, Z.

    2013-10-01

    This catalog summarizes 117 high-confidence >=0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.

  11. THE SECOND FERMI LARGE AREA TELESCOPE CATALOG OF GAMMA-RAY PULSARS

    SciTech Connect

    Abdo, A. A.; Ajello, M.; Allafort, A.; Bloom, E. D.; Bottacini, E.; Baldini, L.; Ballet, J.; Baring, M. G.; Bastieri, D.; Belfiore, A.; Bellazzini, R.; Bregeon, J.; Bhattacharyya, B.; Bissaldi, E.; Bonamente, E.; Brandt, T. J.; Brigida, M.; and others

    2013-10-01

    This catalog summarizes 117 high-confidence ≥0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.

  12. The second FERMI large area telescope catalog of gamma-ray pulsars

    SciTech Connect

    Abdo, A. A.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Belfiore, A.; Bellazzini, R.; Bhattacharyya, B.; Bissaldi, E.; Bloom, E. D.; Bonamente, E.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Burgay, M.; Burnett, T. H.; Busetto, G.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Camilo, F.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chaty, S.; Chaves, R. C. G.; Chekhtman, A.; Chen, A. W.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cognard, I.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; DeCesar, M. E.; De Luca, A.; den Hartog, P. R.; de Palma, F.; Dermer, C. D.; Desvignes, G.; Digel, S. W.; Di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Dumora, D.; Espinoza, C. M.; Falletti, L.; Favuzzi, C.; Ferrara, E. C.; Focke, W. B.; Franckowiak, A.; Freire, P. C. C.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gotthelf, E. V.; Grenier, I. A.; Grondin, M. -H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.; Hessels, J.; Hewitt, J.; Hill, A. B.; Horan, D.; Hou, X.; Hughes, R. E.; Jackson, M. S.; Janssen, G. H.; Jogler, T.; Jóhannesson, G.; Johnson, R. P.; Johnson, A. S.; Johnson, T. J.; Johnson, W. N.; Johnston, S.; Kamae, T.; Kataoka, J.; Keith, M.; Kerr, M.; Knödlseder, J.; Kramer, M.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Lyne, A. G.; Manchester, R. N.; Marelli, M.; Massaro, F.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; McLaughlin, M. A.; Mehault, J.; Michelson, P. F.; Mignani, R. P.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nemmen, R.; Nuss, E.; Ohno, M.; Ohsugi, T.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Parent, D.; Perkins, J. S.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato, G.; Pletsch, H. J.; Porter, T. A.; Possenti, A.; Rainò, S.; Rando, R.; Ransom, S. M.; Ray, P. S.; Razzano, M.; Rea, N.; Reimer, A.; Reimer, O.; Renault, N.; Reposeur, T.; Ritz, S.; Romani, R. W.; Roth, M.; Rousseau, R.; Roy, J.; Ruan, J.; Sartori, A.; Saz Parkinson, P. M.; Scargle, J. D.; Schulz, A.; Sgrò, C.; Shannon, R.; Siskind, E. J.; Smith, D. A.; Spandre, G.; Spinelli, P.; Stappers, B. W.; Strong, A. W.; Suson, D. J.; Takahashi, H.; Thayer, J. G.; Thayer, J. B.; Theureau, G.; Thompson, D. J.; Thorsett, S. E.; Tibaldo, L.; Tibolla, O.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Venter, C.; Vianello, G.; Vitale, V.; Wang, N.; Weltevrede, P.; Winer, B. L.; Wolff, M. T.; Wood, D. L.; Wood, K. S.; Wood, M.; Yang, Z.

    2013-09-19

    This catalog summarizes 117 high-confidence ≥0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.

  13. What limits the achievable areal densities of large aperture space telescopes?

    NASA Astrophysics Data System (ADS)

    Peterson, Lee D.; Hinkle, Jason D.

    2005-08-01

    This paper examines requirements trades involving areal density for large space telescope mirrors. A segmented mirror architecture is used to define a quantitative example that leads to relevant insight about the trades. In this architecture, the mirror consists of segments of non-structural optical elements held in place by a structural truss that rests behind the segments. An analysis is presented of the driving design requirements for typical on-orbit loads and ground-test loads. It is shown that the driving on-orbit load would be the resonance of the lowest mode of the mirror by a reaction wheel static unbalance. The driving ground-test load would be dynamics due to ground-induced random vibration. Two general conclusions are derived from these results. First, the areal density that can be allocated to the segments depends on the depth allocated to the structure. More depth in the structure allows the allocation of more mass to the segments. This, however, leads to large structural depth that might be a significant development challenge. Second, the requirement for ground-test-ability results in an order of magnitude or more depth in the structure than is required by the on-orbit loads. This leads to the proposition that avoiding ground test as a driving requirement should be a fundamental technology on par with the provision of deployable depth. Both are important structural challenges for these future systems.

  14. Inquiry-Based Educational Design for Large-Scale High School Astronomy Projects Using Real Telescopes

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Michael; McKinnon, David H.; Danaia, Lena

    2015-12-01

    In this paper, we outline the theory behind the educational design used to implement a large-scale high school astronomy education project. This design was created in response to the realization of ineffective educational design in the initial early stages of the project. The new design follows an iterative improvement model where the materials and general approach can evolve in response to solicited feedback. The improvement cycle concentrates on avoiding overly positive self-evaluation while addressing relevant external school and community factors while concentrating on backward mapping from clearly set goals. Limiting factors, including time, resources, support and the potential for failure in the classroom, are dealt with as much as possible in the large-scale design allowing teachers the best chance of successful implementation in their real-world classroom. The actual approach adopted following the principles of this design is also outlined, which has seen success in bringing real astronomical data and access to telescopes into the high school classroom.

  15. Wavefront reconstruction for extremely large telescopes via CuRe with domain decomposition.

    PubMed

    Rosensteiner, Matthias

    2012-11-01

    The Cumulative Reconstructor is an accurate, extremely fast reconstruction algorithm for Shack-Hartmann wavefront sensor data. But it has shown an unacceptable high noise propagation for large apertures. Therefore, in this paper we describe a domain decomposition approach to deal with this drawback. We show that this adaptation of the algorithm gives the same reconstruction quality as the original algorithm and leads to a significant improvement with respect to noise propagation. The method is combined with an integral control and compared to the classical matrix vector multiplication algorithm on an end-to-end simulation of a single conjugate adaptive optics system. The reconstruction time is 20n (number of subapertures), and the method is parallelizable.

  16. Telescopic Topics: The Impact of Student-Created Podcasts in a Large, General Education Course

    NASA Astrophysics Data System (ADS)

    Kraal, E. R.

    2014-12-01

    Large, general education courses are important to the geoscience community. These courses serve as valuable recruiting tools for future geoscience majors because over 55% of geoscience students select their major in the first two years of college (Wilson, 2013). These courses can have many challenges such as large class sizes, limited (or no) laboratory time and facilities, little financial resource support, non-permanent faculty, and a variety of student abilities and needs. High impact practices, such as writing courses, student research, and community service can be difficult to integrate into large, non-major courses. Student-produced audio (e. g. podcasts) provide one approach to providing high impact practices within these courses. Other researchers have found student produced audio to be effective at transmitting content, integrating place based experiences, and building community connections within the students. Here I present the implementation of student-created audio within a large (100+), general education course (AST 30 - Mission to the Planets) over the last 4 years called 'Telescopic Topics.' Activities scaffold the students through the semester where they select a topic on planetary science, work with the science reference librarian, visit the writing center, and record their podcast at campus student radio station. The top podcasts are then aired on the campus radio station during the news broadcasts through a rotating series. Surveys of student experiences find that student find the activity valuable and engaging. Students reported feeling less intimidated by the science content and more connected to the subject matter. In addition, it provides many of them with their first introduction to and use of the university library and associated campus resources.

  17. Astronomers Break Ground on Atacama Large Millimeter Array (ALMA) - World's Largest Millimeter Wavelength Telescope

    NASA Astrophysics Data System (ADS)

    2003-11-01

    Scientists and dignitaries from Europe, North America and Chile are breaking ground today (Thursday, November 6, 2003) on what will be the world's largest, most sensitive radio telescope operating at millimeter wavelengths . ALMA - the "Atacama Large Millimeter Array" - will be a single instrument composed of 64 high-precision antennas located in the II Region of Chile, in the District of San Pedro de Atacama, at the Chajnantor altiplano, 5,000 metres above sea level. ALMA 's primary function will be to observe and image with unprecedented clarity the enigmatic cold regions of the Universe, which are optically dark, yet shine brightly in the millimetre portion of the electromagnetic spectrum. The Atacama Large Millimeter Array (ALMA) is an international astronomy facility. ALMA is an equal partnership between Europe and North America, in cooperation with the Republic of Chile, and is funded in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC), and in Europe by the European Southern Observatory (ESO) and Spain. ALMA construction and operations are led on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI), and on behalf of Europe by ESO. " ALMA will be a giant leap forward for our studies of this relatively little explored spectral window towards the Universe" , said Dr. Catherine Cesarsky , Director General of ESO. "With ESO leading the European part of this ambitious and forward-looking project, the impact of ALMA will be felt in wide circles on our continent. Together with our partners in North America and Chile, we are all looking forward to the truly outstanding opportunities that will be offered by ALMA , also to young scientists and engineers" . " The U.S. National Science Foundation joins today with our North American partner, Canada, and with the European Southern Observatory, Spain, and Chile to prepare

  18. The 30-m radio telescope for millimeter astronomy - A new large instrument for German astronomy

    NASA Astrophysics Data System (ADS)

    Baars, J. W. M.; Mezger, P. G.; de Jonge, M. J.; Hooghoudt, B. G.

    1986-08-01

    The instrument considered represents currently the radio telescope with the best performance for astronomical studies involving the wavelength range in the vicinity of 1 mm. For a time of approximately one year, the telescope has been employed in astronomical observational programs. The time period between the planning stage and the beginning of the operational phase is considered. In connection with the opportunities for astronomical studies in the millimeter wavelength range, the new instrument was designed especially for observations involving the range from 0.8 mm to 3 mm. Planning operations for this telescope began already in 1972. Attention is given to discussions with French and British scientists, the selection of a location for the instrument in southern Spain, aspects of European cooperation regarding the instrument, the design of radio telescopes for millimeter astronomy, the characteristic features of the new instrument, data processing and evaluation, and the first results obtained with the telescope.

  19. Low velocity tracking control-based ADRC for large-scale telescope system

    NASA Astrophysics Data System (ADS)

    Cai, Huaxiang; Huang, Yongmei; Du, Junfeng; Tang, Tao; Zuo, Dan

    2015-10-01

    In this paper, an improved Active Disturbance Rejection control (ADRC) method is proposed to enhance the tracking precision of telescope if the telescope runs in a low velocity. Low velocity telescope system usually suffers some obvious nonlinear disturbances, such as nonlinear friction and unknown external disturbance. Thereby, to ensure the tracking precision, multiple loops control structure is a common control method in telescope system, which includes current loop, velocity loop and position loop. The proposed control method is used in the velocity loop which consists of a PD controller and an Extend State Observer (ESO). The ESO is designed to estimate the disturbance involved in the telescope system. Besides, the PD controller is designed to stabilize the closed-loop system. Furthermore, this control method theoretically guarantees a prescribed tracking performance and final tracking accuracy. Finally, the experiment results show that the proposed control method has excellent performance for reducing the tracking error of low velocity.

  20. A testing facility at the Asiago Copernico telescope in the framework of the ADaptive Optics National laboratory of Italy: ADONI

    NASA Astrophysics Data System (ADS)

    Chinellato, Simonetta; Ragazzoni, Roberto; Farinato, Jacopo; Greggio, Davide; Benetti, Stefano; Bergomi, Maria; Biondi, Federico; Cappellaro, Enrico; Carolo, Elena; Chiomento, Venerio; Dima, Marco; Frigo, Aldo; Gullieuszik, Marco; Lessio, Luigi; Magrin, Demetrio; Marafatto, Luca; Martorana, Giorgio; Portaluri, Elisa; Rebeschini, Mauro; Tomasella, Lina; Traverso, Luciano; Turatto, Massimo; Vassallo, Daniele; Viotto, Valentina

    2016-07-01

    In the context of ADONI, the newly constituted laboratory for INAF Adaptive Optics activities, it is foreseen to set-up a facility accessible to the Italian and international AO community, with the purpose of facilitating the testing of critical sub-systems or components (which may be part of instruments under construction), or prototypes of innovative concepts which may require on-sky demonstrations. The 182cm Copernico Telescope located in Asiago (Italy) has been selected to be a suitable place to set-up this public facility, where a common optical bench will be made available at the Coudé focus to host visiting instrumentation. In this paper we describe the opto-mechanical train to the Coudé focal station to be implemented for the laboratory set-up, and we sketch out the foreseen telescope refurbishing activities to implement this multi-purpose testing facility dedicated to AO related projects.

  1. Probing Millisecond Pulsar Emission Geometry Using Light Curves From the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Venter, Christo; Harding, Alice; Guillemot, L.

    2009-01-01

    An interesting new high-energy pulsar sub-population is emerging following early discoveries of gamma-ray millisecond pulsars (MSPs) by the Fermi Large Area Telescope (LAT). We present results from 3D emission modeling, including the Special Relativistic effects of aberration and time-of-flight delays and also rotational sweepback of 13-field lines, in the geometric context of polar cap (PC), slot gap (SG), outer gap (OG), and two-pole caustic (TPC) pulsar models. In contrast to the general belief that these very old, rapidly-rotating neutron stars (NSs) should have largely pair-starved magnetospheres due to the absence of significant pair production, we find that most of the light curves are best fit by SG and OG models, which indicates the presence of narrow accelerating gaps limited by robust pair production -- even in these pulsars with very low spin-down luminosities. The gamma-ray pulse shapes and relative phase lags with respect to the radio pulses point to high-altitude emission being dominant for all geometries. We also find exclusive differentiation of the current gamma-ray MSP population into two MSP sub-classes: light curve shapes and lags across wavebands impose either pair-starved PC (PSPC) or SG / OG-type geometries. In the first case, the radio pulse has a small lag with respect to the single gamma-ray pulse, while the (first) gamma-ray peak usually trails the radio by a large phase offset in the latter case. Finally, we find that the flux correction factor as a function of magnetic inclination and observer angles is typically of order unity for all models. Our calculation of light curves and flux correction factor f(_, _, P) for the case of MSPs is therefore complementary to the "ATLAS paper" of Watters et al. for younger pulsars.

  2. A Holistic Management Architecture for Large-Scale Adaptive Networks

    DTIC Science & Technology

    2007-09-01

    MANAGEMENT ARCHITECTURE FOR LARGE-SCALE ADAPTIVE NETWORKS by Michael R. Clement September 2007 Thesis Advisor: Alex Bordetsky Second Reader...TECHNOLOGY MANAGEMENT from the NAVAL POSTGRADUATE SCHOOL September 2007 Author: Michael R. Clement Approved by: Dr. Alex ...achieve in life is by His will. Ad Majorem Dei Gloriam. To my parents, my family, and Caitlin: For supporting me, listening to me when I got

  3. Commissioning the polarimetric modes of the Robert Stobie spectrograph on the Southern African Large Telescope

    NASA Astrophysics Data System (ADS)

    Potter, S. B.; Nordsieck, Ken; Romero-Colmenero, Encarni; Crawford, Steve; Vaisanen, Petri; Depagne, Éric; Buckley, David; Koeslag, Anthony; Brink, Janus; Hetlage, Christian; Browne, Keith; Crause, Lisa; Schier, Alan; Allington, James

    2016-08-01

    The Robert Stobie Spectrograph is currently the main workhorse spectroscopic instrument on the Southern African Large Telescope (SALT), which has been undergoing regular scientific operations since 2011. The visible beam of the RSS was designed to perform polarimetry in all of its modes, imaging and grating spectroscopy (with Multi Object Spectroscopy capability) from 3200 to 9000 Å. The polarimetric field of view is 4×8 arcmin. Initial early commissioning of the polarimetric modes was stalled in 2011 because a coupling fluid leak developed in the polarizing beamsplitter after less than a year of operation. As a result, it was decided to redesign the beamsplitter to use a different optical couplant. This was complicated by the unusual thermal expansion properties of the calcite optic, and by the necessity of aligning the individual elements in the beamsplitter mosaic (RSS is the first instrument to use a mosaic beamsplitter). Laboratory work selected a new couplant: a gel, Nye 451. Testing was completed with satisfactory results on a "sacrificial" calcite prism with the same geometry as an actual mosaic element. A successful assembly was performed and the beamsplitter was re-installed in SALT in mid-2015. We describe results from the renewed commissioning efforts to characterize polarimetry from SALT and include some early performance verification science.

  4. Exploring model based engineering for large telescopes: getting started with descriptive models

    NASA Astrophysics Data System (ADS)

    Karban, R.; Zamparelli, M.; Bauvir, B.; Koehler, B.; Noethe, L.; Balestra, A.

    2008-07-01

    Large telescopes pose a continuous challenge to systems engineering due to their complexity in terms of requirements, operational modes, long duty lifetime, interfaces and number of components. A multitude of decisions must be taken throughout the life cycle of a new system, and a prime means of coping with complexity and uncertainty is using models as one decision aid. The potential of descriptive models based on the OMG Systems Modeling Language (OMG SysMLTM) is examined in different areas: building a comprehensive model serves as the basis for subsequent activities of soliciting and review for requirements, analysis and design alike. Furthermore a model is an effective communication instrument against misinterpretation pitfalls which are typical of cross disciplinary activities when using natural language only or free-format diagrams. Modeling the essential characteristics of the system, like interfaces, system structure and its behavior, are important system level issues which are addressed. Also shown is how to use a model as an analysis tool to describe the relationships among disturbances, opto-mechanical effects and control decisions and to refine the control use cases. Considerations on the scalability of the model structure and organization, its impact on the development process, the relation to document-centric structures, style and usage guidelines and the required tool chain are presented.

  5. OBSERVATIONS OF ENERGETIC HIGH MAGNETIC FIELD PULSARS WITH THE FERMI LARGE AREA TELESCOPE

    SciTech Connect

    Parent, D.; Abdo, A. A.; Kerr, M.; Den Hartog, P. R.; Romani, R. W.; Watters, K.; Craig, H. A.; Baring, M. G.; DeCesar, M. E.; Harding, A. K.; Espinoza, C. M.; Stappers, B. W.; Weltevrede, P.; Gotthelf, E. V.; Camilo, F.; Johnston, S.; Kaspi, V. M.; Livingstone, M.; Burgay, M.; Freire, P. C. C. E-mail: kerrm@stanford.edu; and others

    2011-12-20

    We report the detection of {gamma}-ray pulsations from the high-magnetic-field rotation-powered pulsar PSR J1119-6127 using data from the Fermi Large Area Telescope. The {gamma}-ray light curve of PSR J1119-6127 shows a single, wide peak offset from the radio peak by 0.43 {+-} 0.02 in phase. Spectral analysis suggests a power law of index 1.0 {+-} 0.3{sup +0.4}{sub -0.2} with an energy cutoff at 0.8 {+-} 0.2{sup +2.0}{sub -0.5} GeV. The first uncertainty is statistical and the second is systematic. We discuss the emission models of PSR J1119-6127 and demonstrate that despite the object's high surface magnetic field-near that of magnetars-the field strength and structure in the {gamma}-ray emitting zone are apparently similar to those of typical young pulsars. Additionally, we present upper limits on the {gamma}-ray pulsed emission for the magnetically active PSR J1846-0258 in the supernova remnant Kesteven 75 and two other energetic high-B pulsars, PSRs J1718-3718 and J1734-3333. We explore possible explanations for the non-detection of these three objects, including peculiarities in their emission geometry.

  6. Recent Results on SNRs and PWNe from the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Hays, Elizabeth

    2010-01-01

    Topics include: Fermi LAT Collaboration groups; galactic results from LAT; a GeV, wide-field instrument; the 1FGL catalog, the Fermi LAT 1FGL source catalog, unidentified gamma-ray sources; variability in 1FGL sources; curvature in 1FGL sources; spectral-variability classification; pulsars and their wind nebulae; gamma-ray pulsars and MSPs; GeV PWN search; Crab pulsar and nebula; Vela X nebular of Vela pulsar; MSH 15-52; supernova remnants, resolved GeV sources, galactic transients, LAT unassociated transient detections; gamma rays from a nova; V407 Cyngi - a symbiotic nova; V407 Cygni: a variable star; and March 11 - a nova. Summary slides include pulsars everywhere, blazars, LAT as an electron detector, cosmic ray spectrum, the Large Area Telescope, the Fermi Observatory, LAT sensitivity with time, candidate gamma-ray events, on-orbit energy calibration and rate, a 1 year sky map, LAT automated science processing, reported GeV flares, early activity and spectacular flare, gamma-ray transients near the galactic plane , two early unassociated transients, counter part search - Fermi J0910-5404; counterpart search 3EG J0903-3531, and a new LAT transient - J1057-6027.

  7. 8 Meter Advanced Technology Large-Aperture Space Telescope (ATLAST-8m)

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2010-01-01

    ATLAST-8m (Advanced Technology Large Aperture Space Telescope) is a proposed 8-meter monolithic UV/optical/NIR space observatory (wavelength range 110 to 2500 nm) to be placed in orbit at Sun-Earth L2 by NASA's planned Ares V heavy lift vehicle. Given its very high angular resolution (15 mas @ 500 nm), sensitivity and performance stability, ATLAST-8m is capable of achieving breakthroughs in a broad range of astrophysics including: Is there life elsewhere in the Galaxy? An 8-meter UVOIR observatory has the performance required to detect habitability (H2O, atmospheric column density) and biosignatures (O2, O3, CH4) in terrestrial exoplanet atmospheres, to reveal the underlying physics that drives star formation, and to trace the complex interactions between dark matter, galaxies, and intergalactic medium. The ATLAST Astrophysics Strategic Mission Concept Study developed a detailed point design for an 8-m monolithic observatory including optical design; structural design/analysis including primary mirror support structure, sun shade and secondary mirror support structure; thermal analysis; spacecraft including structure, propulsion, GN&C, avionics, power systems and reaction wheels; mass and power budgets; and system cost. The results of which were submitted by invitation to NRC's 2010 Astronomy & Astrophysics Decadal Survey.

  8. FERMI LARGE AREA TELESCOPE CONSTRAINTS ON THE GAMMA-RAY OPACITY OF THE UNIVERSE

    SciTech Connect

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Allafort, A.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Atwood, W. B.; Baldini, L.; Bellazzini, R.; Ballet, J.; Baring, M. G.; Bastieri, D.; Baughman, B. M.; Bhat, P. N.; Bonamente, E. E-mail: bouvier@stanford.ed E-mail: silvia.raino@ba.infn.i E-mail: lreyes@kicp.uchicago.ed

    2010-11-10

    The extragalactic background light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above {approx}10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the {gamma}-ray flux of extragalactic sources such as blazars and gamma-ray bursts (GRBs). The Large Area Telescope on board Fermi detects a sample of {gamma}-ray blazars with redshift up to z {approx} 3, and GRBs with redshift up to z {approx} 4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of {gamma}-ray flux attenuation by the EBL. We place upper limits on the {gamma}-ray opacity of the universe at various energies and redshifts and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the 'baseline' model of Stecker et al. can be ruled out with high confidence.

  9. The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) 2005: Calibration and Targeted Sources

    NASA Astrophysics Data System (ADS)

    Truch, M. D. P.; Ade, P. A. R.; Bock, J. J.; Chapin, E. L.; Devlin, M. J.; Dicker, S.; Griffin, M.; Gundersen, J. O.; Halpern, M.; Hargrave, P. C.; Hughes, D. H.; Klein, J.; Marsden, G.; Martin, P. G.; Mauskopf, P.; Netterfield, C. B.; Olmi, L.; Pascale, E.; Patanchon, G.; Rex, M.; Scott, D.; Semisch, C.; Tucker, C.; Tucker, G. S.; Viero, M. P.; Wiebe, D. V.

    2008-07-01

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) operated successfully during a 100 hr flight from northern Sweden in 2005 June (BLAST05). As part of the calibration and pointing procedures, several compact sources were mapped, including solar system, Galactic, and extragalactic targets, specifically Pallas, CRL 2688, LDN 1014, IRAS 20126+4104, IRAS 21078+5211, IRAS 21307+5049, IRAS 22134+5834, IRAS 23011+6126, K3-50, W75N, and Mrk 231. One additional source, Arp 220, was observed and used as our primary calibrator. Details of the overall BLAST05 calibration procedure are discussed here. The BLAST observations of each compact source are described, flux densities and spectral energy distributions are reported, and these are compared with previous measurements at other wavelengths. The 250, 350, and 500 μm BLAST data can provide useful constraints to the amplitude and slope of the submillimeter continuum, which in turn may be useful for the improved calibration of other submillimeter instruments.

  10. Nulling Data Reduction and On-Sky Performance of the Large Binocular Telescope Interferometer

    NASA Technical Reports Server (NTRS)

    Defrere, D.; Hinz, P. M.; Mennesson, B.; Hoffman, W. F.; Millan-Gabet, R.; Skemer, A. J.; Bailey, V.; Danchi, W. C.; Downy, E. C.; Durney, O.; Grenz, P.; Hill, J. M.; McMahon, T. J.; Montoya, M.; Spalding, E.; Vaz, A.; Absil, O.; Arbo, P.; Roberge, A.

    2016-01-01

    The Large Binocular Telescope Interferometer (LBTI) is a versatile instrument designed for high angular resolution and high-contrast infrared imaging (1.5-13 micrometers). In this paper, we focus on the mid-infrared (8-13 micrometers) nulling mode and present its theory of operation, data reduction, and on-sky performance as of the end of the commissioning phase in 2015 March. With an interferometric baseline of 14.4 m, the LBTI nuller is specifically tuned to resolve the habitable zone of nearby main-sequence stars, where warm exozodiacal dust emission peaks. Measuring the exozodi luminosity function of nearby main-sequence stars is a key milestone to prepare for future exo-Earth direct imaging instruments. Thanks to recent progress in wavefront control and phase stabilization, as well as in data reduction techniques, the LBTI demonstrated in 2015 February a calibrated null accuracy of 0.05% over a 3 hr long observing sequence on the bright nearby A3V star Beta Leo. This is equivalent to an exozodiacal disk density of 15-30 zodi for a Sun-like star located at 10 pc, depending on the adopted disk model. This result sets a new record for high-contrast mid-infrared interferometric imaging and opens a new window on the study of planetary systems.

  11. A new measurement of cosmic-ray electrons and positrons with the Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Manfreda, Alberto; Fermi-LAT Collaboration

    2017-01-01

    We present an updated measurement of the cosmic-ray electron and positron spectrum between 7 GeV and 2 TeV, based on 7 years of data collected with the Fermi Large Area Telescope (LAT). The LAT is the first space-based instrument to directly explore the region above 1 TeV. At such high energies, the shape of the spectrum can provide useful information about the origin and propagation of cosmic-ray electrons in the nearby Galactic space. The best fit to the spectrum that we measure is given by a broken power-law, with the break located at 53 +/-8 GeV. Such break, however, is not significant when all the systematic uncertainties are taken into account. Above 50 GeV our data are well described by a single power law with a spectral index of 3.07 +/- 0.02 (stat + syst) +/- 0.06 (energy scale). An exponential cut-off lower than 1.7 TeV is excluded at 95% CL.

  12. Distribution-dependent total exoplanet yield for a large aperture space telescope

    NASA Astrophysics Data System (ADS)

    Morris, Evan; Schiminovich, David

    2017-01-01

    A major scientific goal for future large aperture space telescopes is the discovery and characterization of habitable earth-like planets around FGK+M stars out to 10-20 pc. Using the design and observing plan for such a mission, we calculated the total exoplanet yield of a direct imaging survey, with detections including but not limited to potential earth analogs. In light of uncertainty of exoplanet occurrence rates, we used several of the best available exoplanetary distribution functions and assumed architectures to produce a Monte Carlo simulation of nearby planetary systems and observational parameters, and assessed detectability across the sample. Our calculations show a range of yields depending on the assumed distribution functions. We also compare our predictions to those of other detection methods in order to identify areas of parameter space (e.g. radius, period) uniquely constrained by direct imaging. In general, our calculations suggest that a higher completeness can be achieved with direct imaging, which will allow for calculation of a more accurate occurrence rate in local space.

  13. The First Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope

    NASA Astrophysics Data System (ADS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Allafort, A.; Antolini, E.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bogart, J. R.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Cannon, A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Çelik, Ö.; Celotti, A.; Charles, E.; Chekhtman, A.; Chen, A. W.; Cheung, C. C.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Costamante, L.; Cotter, G.; Cutini, S.; D'Elia, V.; Dermer, C. D.; de Angelis, A.; de Palma, F.; De Rosa, A.; Digel, S. W.; Silva, E. do Couto e.; Drell, P. S.; Dubois, R.; Dumora, D.; Escande, L.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fortin, P.; Frailis, M.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giebels, B.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grandi, P.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Harding, A. K.; Hayashida, M.; Hays, E.; Healey, S. E.; Hill, A. B.; Horan, D.; Hughes, R. E.; Iafrate, G.; Itoh, R.; Jóhannesson, G.; Johnson, A. S.; Johnson, R. P.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kerr, M.; Knödlseder, J.; Kuss, M.; Lande, J.; Latronico, L.; Lavalley, C.; Lemoine-Goumard, M.; Llena Garde, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Makeev, A.; Malaguti, G.; Massaro, E.; Mazziotta, M. N.; McConville, W.; McEnery, J. E.; McGlynn, S.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piranomonte, S.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Reposeur, T.; Ripken, J.; Ritz, S.; Rodriguez, A. Y.; Romani, R. W.; Roth, M.; Ryde, F.; Sadrozinski, H. F.-W.; Sanchez, D.; Sander, A.; Saz Parkinson, P. M.; Scargle, J. D.; Sgrò, C.; Shaw, M. S.; Siskind, E. J.; Smith, P. D.; Spandre, G.; Spinelli, P.; Starck, J.-L.; Stawarz, Ł.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Taylor, G. B.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Ubertini, P.; Uchiyama, Y.; Usher, T. L.; Vasileiou, V.; Vilchez, N.; Villata, M.; Vitale, V.; Waite, A. P.; Wallace, E.; Wang, P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Ylinen, T.; Ziegler, M.

    2010-05-01

    We present the first catalog of active galactic nuclei (AGNs) detected by the Large Area Telescope (LAT), corresponding to 11 months of data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 γ-ray sources located at high Galactic latitudes (|b|>10°) that are detected with a test statistic greater than 25 and associated statistically with AGNs. Some LAT sources are associated with multiple AGNs, and consequently, the catalog includes 709 AGNs, comprising 300 BL Lacertae objects, 296 flat-spectrum radio quasars, 41 AGNs of other types, and 72 AGNs of unknown type. We also classify the blazars based on their spectral energy distributions as archival radio, optical, and X-ray data permit. In addition to the formal 1LAC sample, we provide AGN associations for 51 low-latitude LAT sources and AGN "affiliations" (unquantified counterpart candidates) for 104 high-latitude LAT sources without AGN associations. The overlap of the 1LAC with existing γ-ray AGN catalogs (LBAS, EGRET, AGILE, Swift, INTEGRAL, TeVCat) is briefly discussed. Various properties—such as γ-ray fluxes and photon power-law spectral indices, redshifts, γ-ray luminosities, variability, and archival radio luminosities—and their correlations are presented and discussed for the different blazar classes. We compare the 1LAC results with predictions regarding the γ-ray AGN populations, and we comment on the power of the sample to address the question of the blazar sequence.

  14. Nulling Data Reduction and On-sky Performance of the Large Binocular Telescope Interferometer

    NASA Astrophysics Data System (ADS)

    Defrère, D.; Hinz, P. M.; Mennesson, B.; Hoffmann, W. F.; Millan-Gabet, R.; Skemer, A. J.; Bailey, V.; Danchi, W. C.; Downey, E. C.; Durney, O.; Grenz, P.; Hill, J. M.; McMahon, T. J.; Montoya, M.; Spalding, E.; Vaz, A.; Absil, O.; Arbo, P.; Bailey, H.; Brusa, G.; Bryden, G.; Esposito, S.; Gaspar, A.; Haniff, C. A.; Kennedy, G. M.; Leisenring, J. M.; Marion, L.; Nowak, M.; Pinna, E.; Powell, K.; Puglisi, A.; Rieke, G.; Roberge, A.; Serabyn, E.; Sosa, R.; Stapeldfeldt, K.; Su, K.; Weinberger, A. J.; Wyatt, M. C.

    2016-06-01

    The Large Binocular Telescope Interferometer (LBTI) is a versatile instrument designed for high angular resolution and high-contrast infrared imaging (1.5-13 μm). In this paper, we focus on the mid-infrared (8-13 μm) nulling mode and present its theory of operation, data reduction, and on-sky performance as of the end of the commissioning phase in 2015 March. With an interferometric baseline of 14.4 m, the LBTI nuller is specifically tuned to resolve the habitable zone of nearby main-sequence stars, where warm exozodiacal dust emission peaks. Measuring the exozodi luminosity function of nearby main-sequence stars is a key milestone to prepare for future exo-Earth direct imaging instruments. Thanks to recent progress in wavefront control and phase stabilization, as well as in data reduction techniques, the LBTI demonstrated in 2015 February a calibrated null accuracy of 0.05% over a 3 hr long observing sequence on the bright nearby A3V star β Leo. This is equivalent to an exozodiacal disk density of 15-30 zodi for a Sun-like star located at 10 pc, depending on the adopted disk model. This result sets a new record for high-contrast mid-infrared interferometric imaging and opens a new window on the study of planetary systems.

  15. European Extremely Large Telescope Site Characterization. II. High Angular Resolution Parameters

    NASA Astrophysics Data System (ADS)

    Vázquez Ramió, Héctor; Vernin, Jean; Muñoz-Tuñón, Casiana; Sarazin, Marc; Varela, Antonia M.; Trinquet, Hervé; Delgado, José Miguel; Fuensalida, Jesús J.; Reyes, Marcos; Benhida, Abdelmajid; Benkhaldoun, Zouhair; García Lambas, Diego; Hach, Youssef; Lazrek, M.; Lombardi, Gianluca; Navarrete, Julio; Recabarren, Pablo; Renzi, Victor; Sabil, Mohammed; Vrech, Rubén

    2012-08-01

    This is the second article of a series devoted to European Extremely Large Telescope (E-ELT) site characterization. In this article we present the main properties of the parameters involved in high angular resolution observations from the data collected in the site testing campaign of the E-ELT during the design study (DS) phase. Observations were made in 2008 and 2009, in the four sites selected to shelter the future E-ELT (characterized under the ELT-DS contract): Aklim mountain in Morocco, Observatorio del Roque de los Muchachos (ORM) in Spain, Macón range in Argentina, and Cerro Ventarrones in Chile. The same techniques, instruments, and acquisition procedures were taken on each site. A multiple aperture scintillation sensor (MASS) and a differential image motion monitor (DIMM) were installed at each site. Global statistics of the integrated seeing, the free atmosphere seeing, the boundary layer seeing, and the isoplanatic angle were studied for each site, and the results are presented here. In order to estimate other important parameters, such as the coherence time of the wavefront and the overall parameter “coherence étendue,” additional information of vertical profiles of the wind speed was needed. Data were retrieved from the National Oceanic and Atmospheric Administration (NOAA) archive. Ground wind speed was measured by automatic weather stations (AWS). More aspects of the turbulence parameters, such as their seasonal trend, their nightly evolution, and their temporal stability, were also obtained and analyzed.

  16. Enabling Opportunities for Large Space Telescopes in the Era of the Exploration Initiative

    NASA Astrophysics Data System (ADS)

    Lester, D. F.; Moe, R. V.; Derkowski, B. J.; Friedman, E. J.; Espero, T.; Lillie, C. F.

    2005-05-01

    We discuss enabling opportunities and implementation strategies for human and robotic servicing of a large space telescope operating at the Earth-Sun L2 location. The NASA SAFIR (Single Aperture Far Infrared) Vision Mission is used as a representative strawman case. Following earlier agency studies, we consider "gateway" operations at the Earth-Moon L1 location in a scenario that might involve a Crew Exploration Vehicle (CEV). We assess requirements for that vehicle that would permit such servicing operations. We consider propulsion-economical observatory transfer between L1 and L2, the importance of subsystem modularity, strategies for contamination mitigation and on-orbit integration and test, and the functional relationship of humans and robots, including latency issues for telerobotics. Issues of safety and risk to observatory and personnel are reviewed. Options for in situ servicing at L2 are briefly considered. Opportunities are discussed in the context of value that such an L1 gateway might have to lunar surface efforts and other exploration goals. This work is supported by the NASA Science Mission Directorate.

  17. Constraints on axions and axionlike particles from Fermi Large Area Telescope observations of neutron stars

    NASA Astrophysics Data System (ADS)

    Berenji, B.; Gaskins, J.; Meyer, M.

    2016-02-01

    We present constraints on the nature of axions and axionlike particles (ALPs) by analyzing gamma-ray data from neutron stars using the Fermi Large Area Telescope. In addition to axions solving the strong C P problem of particle physics, axions and ALPs are also possible dark matter candidates. We investigate axions and ALPs produced by nucleon-nucleon bremsstrahlung within neutron stars. We derive a phenomenological model for the gamma-ray spectrum arising from subsequent axion decays. By analyzing five years of gamma-ray data (between 60 and 200 MeV) for a sample of four nearby neutron stars, we do not find evidence for an axion or ALP signal; thus we obtain a combined 95% confidence level upper limit on the axion mass of 7.9 ×10-2 eV , which corresponds to a lower limit for the Peccei-Quinn scale fa of 7.6 ×107 GeV . Our constraints are more stringent than previous results probing the same physical process, and are competitive with results probing axions and ALPs by different mechanisms.

  18. Observations of Energetic High Magnetic Field Pulsars with the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Parent, D.; Kerr, M.; DenHartog, P. R.; Baring, M. G.; DeCesar, M. E.; Espinoza, C. M.; Harding, A. K.; Romani, R. W.; Stappers, B. W.; Watters, K.; Weltevrde, P.; Abdo, A. A.; Craig, H. A.; Kramer, M.; Lyne, A. G.

    2011-01-01

    We report the detection of gamma-ray pulsations from the high-magnetic-field rotation-powered pulsar PSR J1119.6127 using data from the Fermi Large Area Telescope. The gamma-ray light curve of PSR J1119.6127 shows a single, wide peak offset from the radio peak by 0.43 +/- 0.02 in phase. Spectral analysis suggests a power law of index 1.0 +/- 0.3(+0.4 -0.2) with an energy cut-off at 0.8 +/- 0.2(+2.0 -0.5) GeV. The first uncertainty is statistical and the second is systematic. We discuss the emission models of PSR J1119.6127 and demonstrate that despite the object's high surface magnetic field--near that of magnetars -- the field strength and structure in the gamma-ray emitting zone are apparently similar to those of typical young pulsars. Additionally, we present upper limits on the gamma-ray pulsed emission for the magnetically active PSR J1846.0258 in the supernova remnant Kesteven 75 and two other energetic high-Beta pulsars, PSRs J1718.3718 and J1734.3333. We explore possible explanations for the non-detection of these three objects, including peculiarities in their emission geometry.

  19. Deep blank-field catalogue for medium- and large-sized telescopes

    NASA Astrophysics Data System (ADS)

    Jiménez Esteban, F. M.; Cabrera Lavers, A.; Cardiel, N.; Alacid, J. M.

    2012-11-01

    The observation of blank fields, defined as regions of the sky that are devoid of stars down to a given threshold magnitude, constitutes one of the most relevant calibration procedures required for the proper reduction of astronomical data obtained following typical observing strategies. In this work, we have used Delaunay triangulation to search for deep blank fields throughout the whole sky, with a minimum size of 10 arcmin in diameter and an increasing threshold magnitude from 15 to 18 in the R band of the USNO-B Catalog of the United States Naval Observatory. The result is a catalogue with the deepest blank fields known so far. A short sample of these regions has been tested with the 10.4-m Gran Telescopio Canarias, and it has been shown to be extremely useful for medium- and large-sized telescopes. Because some of the regions found could also be suitable for new extragalactic studies, we have estimated the galactic extinction in the direction of each deep blank field. This catalogue is accessible through the virtual observatory tool TESELA, and the user can retrieve - and visualize using ALADIN - the deep blank fields available near a given position in the sky.

  20. APERTURE: a precise extremely large reflective telescope using re-configurable elements

    NASA Astrophysics Data System (ADS)

    Ulmer, M. P.; Coverstone, V. L.; Cao, J.; Chung, Y.-W.; Corbineau, M.-C.; Case, A.; Murchison, B.; Lorenz, C.; Luo, G.; Pekosh, J.; Sepulveda, J.; Schneider, A.; Yan, X.; Ye, S.

    2016-07-01

    One of the pressing needs for the UV-Vis is a design to allow even larger mirrors than the JWST primary at an affordable cost. We report here the results of a NASA Innovative Advanced Concepts phase 1 study. Our project is called A Precise Extremely large Reflective Telescope Using Reconfigurable Elements (APERTURE). The idea is to deploy a continuous membrane-like mirror. The mirror figure will be corrected after deployment to bring it into better or equal lambda/20 deviations from the prescribed mirror shape. The basic concept is not new. What is new is to use a different approach from the classical piezoelectric-patch technology. Instead, our concept is based on a contiguous coating of a so called magnetic smart material (MSM). After deployment a magnetic write head will move on the non-reflecting side of the mirror and will generate a magnetic field that will produce a stress in the MSM that will correct the mirror deviations from the prescribed shape.

  1. EXPECTED LARGE SYNOPTIC SURVEY TELESCOPE (LSST) YIELD OF ECLIPSING BINARY STARS

    SciTech Connect

    Prsa, Andrej; Pepper, Joshua; Stassun, Keivan G.

    2011-08-15

    In this paper, we estimate the Large Synoptic Survey Telescope (LSST) yield of eclipsing binary stars, which will survey {approx}20,000 deg{sup 2} of the southern sky during a period of 10 years in six photometric passbands to r {approx} 24.5. We generate a set of 10,000 eclipsing binary light curves sampled to the LSST time cadence across the whole sky, with added noise as a function of apparent magnitude. This set is passed to the analysis-of-variance period finder to assess the recoverability rate for the periods, and the successfully phased light curves are passed to the artificial-intelligence-based pipeline ebai to assess the recoverability rate in terms of the eclipsing binaries' physical and geometric parameters. We find that, out of {approx}24 million eclipsing binaries observed by LSST with a signal-to-noise ratio >10 in mission lifetime, {approx}28% or 6.7 million can be fully characterized by the pipeline. Of those, {approx}25% or 1.7 million will be double-lined binaries, a true treasure trove for stellar astrophysics.

  2. Systems engineering in the Large Synoptic Survey Telescope project: an application of model based systems engineering

    NASA Astrophysics Data System (ADS)

    Claver, C. F.; Selvy, Brian M.; Angeli, George; Delgado, Francisco; Dubois-Felsmann, Gregory; Hascall, Patrick; Lotz, Paul; Marshall, Stuart; Schumacher, German; Sebag, Jacques

    2014-08-01

    The Large Synoptic Survey Telescope project was an early adopter of SysML and Model Based Systems Engineering practices. The LSST project began using MBSE for requirements engineering beginning in 2006 shortly after the initial release of the first SysML standard. Out of this early work the LSST's MBSE effort has grown to include system requirements, operational use cases, physical system definition, interfaces, and system states along with behavior sequences and activities. In this paper we describe our approach and methodology for cross-linking these system elements over the three classical systems engineering domains - requirement, functional and physical - into the LSST System Architecture model. We also show how this model is used as the central element to the overall project systems engineering effort. More recently we have begun to use the cross-linked modeled system architecture to develop and plan the system verification and test process. In presenting this work we also describe "lessons learned" from several missteps the project has had with MBSE. Lastly, we conclude by summarizing the overall status of the LSST's System Architecture model and our plans for the future as the LSST heads toward construction.

  3. SENSITIVITY OF BLIND PULSAR SEARCHES WITH THE FERMI LARGE AREA TELESCOPE

    SciTech Connect

    Dormody, M.; Johnson, R. P.; Atwood, W. B.; Belfiore, A.; Razzano, M.; Saz Parkinson, P. M.; Grenier, I. A.

    2011-12-01

    We quantitatively establish the sensitivity to the detection of young to middle-aged, isolated, gamma-ray pulsars through blind searches of Fermi Large Area Telescope (LAT) data using a Monte Carlo simulation. We detail a sensitivity study of the time-differencing blind search code used to discover gamma-ray pulsars in the first year of observations. We simulate 10,000 pulsars across a broad parameter space and distribute them across the sky. We replicate the analysis in the Fermi LAT First Source Catalog to localize the sources, and the blind search analysis to find the pulsars. We analyze the results and discuss the effect of positional error and spin frequency on gamma-ray pulsar detections. Finally, we construct a formula to determine the sensitivity of the blind search and present a sensitivity map assuming a standard set of pulsar parameters. The results of this study can be applied to population studies and are useful in characterizing unidentified LAT sources.

  4. Adaptive differences in the body proportions of large felids.

    PubMed

    Gonyea, W J

    1976-01-01

    Body proportions of eight species of large felids were studied and the relationship between their morphology, habitat structure and habitat utilization was analyzed. Both Panthera onca and Neofelis nebulosa are exclusive forest dwellers (found exclusively in high densly structured habitats). These felids have the relatively shortest anterior limbs and lumbar spine. In addition, P. onca has the relatively shortest posterior limbs of the large felids, while the posterior limbs of N. nebulosa are relatively long when compared with those of P. onca which seems to be an adaptation for jumping. All large fields use the anterior limbs to make primary contact with their prey. In addition, the prey taken by the forest fields can exceed their own body weight. On the other hand, the cheetah is found in low structured habitats (savanna), and it has the relatively longest limbs and lumbarspine of the large felids. But the cheetah's prey usually weigh less than its own body weight. The cheetah also employs a 'rapid pursuit phase' in hunting and is capable of overtaking its prey. The lion, however, was found to have the body proportions of a forest felid, yet it also resides in low structured habitats. It is postulated that the utilization of large prey by the lion limits the possibilities for morphological adaptations for speed. To increase hunting efficiency, reproductive success, and territorial defense on the plains, lions form prides.

  5. Advanced electro-optical imaging techniques. [conference papers on sensor technology applicable to Large Space Telescope program

    NASA Technical Reports Server (NTRS)

    Sobieski, S. (Editor); Wampler, E. J. (Editor)

    1973-01-01

    The papers presented at the symposium are given which deal with the present state of sensors, as may be applicable to the Large Space Telescope (LST) program. Several aspects of sensors are covered including a discussion of the properties of photocathodes and the operational imaging camera tubes.

  6. RoboNet-1.0: A Prototype Global Network of Large Robotic Telescopes

    NASA Astrophysics Data System (ADS)

    Bode, M. F.; Cardiff U. Collaboration; U. Hertfordshire Collaboration; U. Leicester Collaboration; St Andrews U. Collaboration; Queens U., Belfast Collaboration; Mullard Space Science Lab. Collaboration; U. Exeter Collaboration; U. Southampton Collaboration; U. Manchester Collaboration

    2004-12-01

    Involving a consortium of 10 UK universities, RoboNet-1.0 comprises the Liverpool Telescope (LT, La Palma), plus specially allocated time on the Faulkes Telescope North (FTN, Maui) and Faulkes Telescope South (FTS, Siding Spring, Australia). All three are essentially identical 2m telescopes equipped for both optical photometry and spectroscopy and operated from a common centre in Liverpool. The LT is primarily for research use whereas the FTs are mainly dedicated to education. Software developed by the eSTAR GRID project is being applied and enhanced to enable efficient and effective operation of the network. The primary scientific projects being addressed by RoboNet-1.0 are (a) rapid follow-up of Gamma Ray Burst sources detected by missions such as Swift, and (b) the detection of extra-solar planets via microlensing. Observations with the network began in August 2004. This is a pre-cursor project to the establishment of the full RoboNet global network of six dedicated telescopes which would greatly enhance work in several important branches of time domain astrophysics. Operation of the Liverpool Telescope and RoboNet-1.0 are funded by the UK Particle Physics and Astronomy Research Council. The Faulkes Telescopes are funded by the Dill Faulkes Educational Trust.

  7. Fermi Large Area Telescope Observations of the Supernova Remnant GS.7-0.1

    NASA Technical Reports Server (NTRS)

    Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Ferrara, E. C.; Harding, A. K.; Hays, E.; Moiseev, A. A.; Troja, E.

    2011-01-01

    We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. An investigation of the relationship among G8.7-0.l and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.l and a lesser part located outside the western boundary of G8.7-0.l. The region of the gamma-ray emission overlaps spatially-connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 +/- 0.6 (stat) +/- 1.2 (sys) GeV, and photon indices of 2.10 +/- 0.06 (stat) +/- 0.10 (sys) below the break and 2.70 +/- 0.12 (stat) +/- 0.l4 (sys) above the break. Given the spatial association among the gamma rays, the radio emission of G8.7-0.1, and the molecular clouds, the decay of 1IoS produced by particles accelerated in the SNR and hitting the molecular clouds naturally explains the GeV gamma-ray spectrum. We also find that the GeV morphology is not well represented by the TeV emission from HESS J1804-216 and that the spectrum in the GeV band is not consistent with the extrapolation of the TeV gamma-ray spectrum. The spectral index of the TeV emission is consistent with the particle spectral index predicted by a theory that assumes energy-dependent diffusion of particles accelerated in an SNR. We discuss the possibility that the TeV spectrum originates from the interaction of particles accelerated in G8.7-0.1 with molecular clouds, and we constrain the diffusion coefficient of the particles.

  8. Fermi Large Area Telescope Observations of the Supernova Remnant GS.7-0.1

    NASA Technical Reports Server (NTRS)

    Ferrara, E. C.; Hays, E.; Troja, E.; Moiseev, A. A.

    2012-01-01

    We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. An investigation of the relationship among G8.7-0.1 and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.1 and a lesser part located outside the western boundary of G8.7-0.1. The region of the gamma-ray emission overlaps spatially-connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 +/- 0.6 (stat) +/- 1.2 (sys) GeV, and photon indices of2.10 +/- 0.06 (stat) +/- 0.10 (sys) below the break and 2.70 +/- 0.12 (stat) +/- 0.14 (sys) above the break. Given the spatial association among the gamma rays, the radio emission ofG8.7-0.1, and the molecular clouds, the decay of pions produced by particles accelerated in the SNR and hitting the molecular clouds naturally explains the GeV gamma-ray spectrum. We also find that the GeV morphology is not well represented by the TeV emission from HESS Jl804-2l6 and that the spectrum in the Ge V band is not consistent with the extrapolation of the TeV gamma-ray spectrum. The spectral index of the TeV emission is consistent with the particle spectral index predicted by a theory that assumes energy-dependent diffusion of particles accelerated in an SNR. We discuss the possibility that the TeV-spectrum originates from the interaction of particles accelerated in G8.7-0.l with molecular clouds, and we constrain the diffusion coefficient of the particles.

  9. FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE CRAB PULSAR AND NEBULA

    SciTech Connect