Sample records for aperture solar telescope

  1. Synthetic aperture radio telescopes

    Microsoft Academic Search

    Ronny Levanda; Amir Leshem

    2010-01-01

    Next-generation radio telescopes will be much larger, more sensitive, have a much larger observation bandwidth, and will be capable of pointing multiple beams simultaneously. Obtaining the sensitivity, resolution, and dynamic range supported by the receivers requires the development of new signal processing techniques for array and atmospheric calibration as well as new imaging techniques that are both more accurate and

  2. Large aperture diffractive space telescope

    DOEpatents

    Hyde, Roderick A. (Livermore, CA)

    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.

  3. Optical aperture synthesis with electronically connected telescopes.

    PubMed

    Dravins, Dainis; Lagadec, Tiphaine; Nuńez, Paul D

    2015-01-01

    Highest resolution imaging in astronomy is achieved by interferometry, connecting telescopes over increasingly longer distances and at successively shorter wavelengths. Here, we present the first diffraction-limited images in visual light, produced by an array of independent optical telescopes, connected electronically only, with no optical links between them. With an array of small telescopes, second-order optical coherence of the sources is measured through intensity interferometry over 180 baselines between pairs of telescopes, and two-dimensional images reconstructed. The technique aims at diffraction-limited optical aperture synthesis over kilometre-long baselines to reach resolutions showing details on stellar surfaces and perhaps even the silhouettes of transiting exoplanets. Intensity interferometry circumvents problems of atmospheric turbulence that constrain ordinary interferometry. Since the electronic signal can be copied, many baselines can be built up between dispersed telescopes, and over long distances. Using arrays of air Cherenkov telescopes, this should enable the optical equivalent of interferometric arrays currently operating at radio wavelengths. PMID:25880705

  4. The solar optical telescope

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Objectives of the Solar Optical Telescope are to study the physics of the Sun on the scale at which many of the important physical processes occur and to attain a resolution of 73km on the Sun or 0.1 arc seconds of angular resolution. Topics discussed in this overview of the Solar Optical Telescope include: why is the Solar Optical Telescope needed; current picture of the Sun's atmosphere and convection zone; scientific problems for the Solar Optical Telescope; a description of the telescope; the facility - science management, contamination control, and accessibility to the instruments; the scientific instruments - a coordinated instrument package for unlocking the Sun's secrets; parameters of the coordinated instrument package; science operations from the Space Shuttle; and the dynamic solar atmosphere.

  5. Latest Results from the Cambridge Optical Aperture Synthesis Telescope

    E-print Network

    Young, John

    Latest Results from the Cambridge Optical Aperture Synthesis Telescope C.A.Haniff 1 , J.E.Baldwin a brief report and discuss progress at the Cam­ bridge Optical Aperture Synthesis Telescope, in particular of synthesis imaging with a separated­element in­ terferometer (Baldwin et al. 1996), our team in Cambridge has

  6. Solar Central Receiver with an Irising Aperture 

    E-print Network

    Galal, T.; Kulaib, A. M.; Abuzaid, M.

    2010-01-01

    . If the aperture is small, it will be inefficient for periods when the solar isolation is inclined due to spillage. However, if the aperture is large, it will be inefficient for periods when the solar isolation is normal, due to excess heat radiation and convection...

  7. Five hundred meter aperture spherical radio telescope (FAST)

    Microsoft Academic Search

    Rendong Nan

    2006-01-01

    Five hundred meter aperture spherical radio telescope (FAST) will be the largest radio telescope in the world. The innovative\\u000a engineering concept and design pave a new road to realizing a huge single dish in the most effective way. Three outstanding\\u000a features of the telescope are the unique karst depressions as the sites, the active main reflector which corrects spherical\\u000a aberration

  8. 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 front aperture filter is integrated with the telescope dome, it will reject heat from the dome and will significantly reduce dome temperature regulation requirements and costs. Also, the filter will protect the telescope optics from dust and other contaminants in the atmosphere. It will be simpler to clean or replace this filter than the telescope primary mirror. It may be necessary to paint the support grid with a highly reflective material to avoid overheating.

  9. A 408MHz aperture synthesis radio telescope

    Microsoft Academic Search

    B. G. Veidt; T. L. Landecker; J. F. Vaneldik; P. E. Dewdney; D. Routledge

    1985-01-01

    This paper describes the addition of a continuum channel at 408 MHz to the Synthesis Telescope'at the Dominion Radio Astrophysical Observatory (DRAO). In its original form, described by Roger et al. [1973], the telescope was designed to receive signals at 1420 MHz and to provide simultaneous correlations of spectral line signals from the 21-cm wavelength line of atomic hydrogen (H

  10. The Advanced Technology Solar Telescope

    Microsoft Academic Search

    C. U. Keller; T. R. Rimmele; F. Hill; S. L. Keil; J. M. Oschmann

    2002-01-01

    The Advanced Technology Solar Telescope is the largest solar optical facility currently under development. The National Solar Observatory and its partners have just started the design and development phase with first light being planned for late this decade. The 4-m telescope will provide an angular resolution down to 0.025 arcsec, a large photon flux for precise magnetic and velocity field

  11. ADVANCED TECHNOLOGY LARGE-APERTURE SPACE TELESCOPE (ATLAST)

    E-print Network

    Sirianni, Marco

    ADVANCED TECHNOLOGY LARGE-APERTURE SPACE TELESCOPE (ATLAST): A TECHNOLOGY ROADMAP FOR THE NEXT = Northrop Grumman Aerospace Systems 8 = Jet Propulsion Laboratory, California Institute of Technology 9 = Johnson Space Flight Center 10 = Princeton University 11 = Jacobs ESTS Group @ MSFC #12;Advanced

  12. 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.

  13. Advanced Technology Solar Telescope optical design

    Microsoft Academic Search

    Eric Hansen; Ron Price; Rob Hubbard

    2006-01-01

    The Advanced Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. Development of this four-meter off-axis solar telescope has presented many optical design challenges including: \\

  14. The Advanced Technology Solar Telescope: Science Drivers and Construction Status

    NASA Astrophysics Data System (ADS)

    Rimmele, Thomas; Berger, Thomas; McMullin, Joseph; Keil, Stephen; Goode, Phil; Knoelker, Michael; Kuhn, Jeff; Rosner, Robert; Casini, Roberto; Lin, Haosheng; Woeger, Friedrich; von der Luehe, Oskar; Tritschler, Alexandra; Atst Team

    2013-04-01

    The 4-meter Advance Technology Solar Telescope (ATST) currently under construction on the 3000 meter peak of Haleakala on Maui, Hawaii will be the world's most powerful solar telescope and the leading ground-based resource for studying solar magnetism. The solar atmosphere is permeated by a 'magnetic carpet' that constantly reweaves itself to control solar irradiance and its effects on Earth's climate, the solar wind, and space weather phenomena such as flares and coronal mass ejections. Precise measurement of solar magnetic fields requires a large-aperture solar telescope capable of resolving a few tens of kilometers on the solar surface. With its 4 meter aperture, the ATST will for the first time resolve magnetic structure at the intrinsic scales of plasma convection and turbulence. The ATST's ability to perform accurate and precise spectroscopic and polarimetric measurements of magnetic fields in all layers of the solar atmosphere, including accurate mapping of the elusive coronal magnetic fields, will be transformative in advancing our understanding of the magnetic solar atmosphere. The ATST will utilize the Sun as an important astro- and plasma-physics "laboratory" demonstrating key aspects of omnipresent cosmic magnetic fields. The ATST construction effort is led by the US National Solar Observatory. State-of-the-art instrumentation will be constructed by US and international partner institutions. The technical challenges the ATST is facing are numerous and include the design of the off-axis main telescope, the development of a high order adaptive optics system that delivers a corrected beam to the instrument laboratory, effective handling of the solar heat load on optical and structural elements, and minimizing scattered light to enable observations of the faint corona. The ATST project has transitioned from design and development to its construction phase. The project has awarded design and fabrication contracts for major telescope subsystems. Site construction has commenced following the successful conclusion of the site permitting process. Science goals and construction status of telescope and instrument systems will be discussed.

  15. Photometric Reverberation Mapping with a Small Aperture Telescope

    NASA Astrophysics Data System (ADS)

    Hood, Carol E.; Rivera, Noah I.; Thackeray-Lacko, Beverly; Powers, Randy M.; Stuckey, Harrison; Watson, Rene; Hood, Michael A.

    2015-01-01

    We present photometric observations of a sample of bright, broad-line AGN in order to monitor variability and verify their black hole masses using the photometric reverberation mapping technique. Observations were taken, primarily remotely, using the 20-inch telescope at the Murillo Family Observatory, a campus-based observatory located on the outskirts of the Southern California metro area, in both monitored and automated mode nightly in BVRI over a period of 2-5 months. We will show the viability of such a technique for small-aperture telescopes in bright-sky locations and discuss the possibilities of extending this program in the future. We also note that undergraduate students (both from 4-year and community colleges) have been and will continue to be instrumental in the success of similar research programs at CSUSB.

  16. The Telescope Control System of the New Solar Telescope at Big Bear Solar Observatory

    E-print Network

    The Telescope Control System of the New Solar Telescope at Big Bear Solar Observatory G. Yang*a, J Telescope (NST) is an advanced solar telescope at Big Bear Solar Observatory (BBSO). It features a 1.6-m the local seeing. The NST Telescope Control System (TCS) is a complex system, which provides powerful

  17. ZERODUR mirror substrates for solar telescopes

    Microsoft Academic Search

    T. Döhring; R. Jedamzik; P. Hartmann

    2007-01-01

    The zero-expansion glass ceramic material, ZERODUR, is well known for nighttime telescope mirror substrates. Also for solar telescopes, ZERODUR is often selected as mirror blank material. Examples are the Swedish 1m Solar Telescope (SST), the balloon-born telescope SUNRISE, and the New Solar Telescope (NST) of the Big Bear Solar Observatory. The properties of ZERODUR are discussed with respect to the

  18. A 16-m Telescope for the Advanced Technology Large Aperture Telescope (ATLAST) Mission

    E-print Network

    Sirianni, Marco

    and is separated from the launch vehicle, its solar arrays and high gain antenna will be deployed for the telescope and its instruments. Solar array panels, an antenna and a solar sail are also folded up against and isolating boom" while the SMSS and PM are deployed. Following this, a sunshade if erected around

  19. ZERODUR mirror substrates for solar telescopes

    NASA Astrophysics Data System (ADS)

    Döhring, T.; Jedamzik, R.; Hartmann, P.

    The zero-expansion glass ceramic material, ZERODUR, is well known for nighttime telescope mirror substrates. Also for solar telescopes, ZERODUR is often selected as mirror blank material. Examples are the Swedish 1m Solar Telescope (SST), the balloon-born telescope SUNRISE, and the New Solar Telescope (NST) of the Big Bear Solar Observatory. The properties of ZERODUR are discussed with respect to the special technical requirements of solar observatories, resulting in the conclusion that mirrors made of this glass ceramic material are an excellent choice for solar telescopes.

  20. 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.

  1. A synthetic aperture radio telescope for ICME observations as a potential payload of SPORT

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Sun, W.; Liu, H.; Xiong, M.; Liu, Y. D.; Wu, J.

    2013-12-01

    We introduce a potential payload for the Solar Polar ORbit Telescope (SPORT), a space weather mission proposed by the National Space Science Center, Chinese Academy of Sciences. This is a synthetic aperture radio imager designed to detect radio emissions from interplanetary coronal mass ejections (ICMEs), which is expected to be an important instrument to monitor the propagation and evolution of ICMEs. The radio telescope applies a synthetic aperture interferometric technique to measure the brightness temperature of ICMEs. Theoretical calculations of the brightness temperature utilizing statistical properties of ICMEs and the background solar wind indicate that ICMEs within 0.35 AU from the Sun are detectable by a radio telescope at a frequency <= 150 MHz with a sensitivity of <=1 K. The telescope employs a time shared double rotation scan (also called a clock scan), where two coplanar antennas revolve around a fixed axis at different radius and speed, to fulfill sampling of the brightness temperature. An array of 4+4 elements with opposite scanning directions are developed for the radio telescope to achieve the required sensitivity (<=1K) within the imaging refreshing time (~30 minutes). This scan scheme is appropriate for a three-axis stabilized spacecraft platform while keeping a good sampling pattern. We also discuss how we select the operating frequency, which involves a trade-off between the engineering feasibility and the scientific goal. Our preliminary results indicate that the central frequency of 150 MHz with a bandwidth of 20 MHz, which requires arm lengths of the two groups of 14m and 16m, respectively, gives an angular resolution of 2°, a field of view of ×25° around the Sun, and a time resolution of 30 minutes.

  2. Active Optics for a 16-Meter Advanced Technology Large Aperture Space Telescope

    E-print Network

    Sirianni, Marco

    Active Optics for a 16-Meter Advanced Technology Large Aperture Space Telescope David C. Redding. Unwin, M. Werner Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA, USA 91109-optics Advanced Technology Large Aperture Space Telescope, to be launched by the Ares V Heavy Lift Vehicle

  3. The Advanced Technology Solar Telescope - Constructing The World's Largest Solar Telescope

    NASA Astrophysics Data System (ADS)

    Rimmele, Thomas R.; Keil, S.; Wagner, J.; ATST Team

    2011-05-01

    The 4m Advance Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading ground-based resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. The ATST shall provide high resolution and high sensitivity observations of the dynamic solar magnetic fields throughout the solar atmosphere, including the corona at infrared wavelengths. With its 4 m aperture, ATST will resolve features at 0.03" at visible wavelengths and obtain 0.1" resolution at the magnetically highly sensitive near infrared wavelengths. A high order adaptive optics system delivers a corrected beam to the initial set of five state-of-the-art, facility class instrumentation located in the coude laboratory facility. Coronal magnetometry and spectroscopy will be performed by two of these instruments at infrared wavelengths. In January 2010 the ATST project transitioned from design and development to the construction phase. The project has awarded contracts for major subsystems, including the 4m primary mirror, architectural and engineering services related to the Support Facilities, Enclosure construction design, Telescope Mount Assembly, and Facilities Thermal System construction design. The State of Hawai'I Board of Land and Natural Resources approved the Conservation District Use Permit submitted by the University of Hawai'I at their December 6, 2010 meeting in Honolulu, HI. A brief overview of the science goals and observational requirements of the ATST will be given, followed by a summary of the project status of the telescope and discussion of the approach to integrating instruments into the facility.

  4. High-contrast visible nulling coronagraph for segmented and arbitrary telescope apertures

    NASA Astrophysics Data System (ADS)

    Hicks, Brian A.; Lyon, Richard G.; Bolcar, Matthew R.; Clampin, Mark; Petrone, Peter

    2014-08-01

    Exoplanet coronagraphy will be driven by the telescope architectures available and thus the system designer must have available one or more suitable coronagraphic instrument choices that spans the set of telescope apertures, including filled (off-axis), obscured (e.g. with secondary mirror spiders and struts), segmented apertures, such as JWST, and interferometric apertures. In this work we present one such choice of coronagraph, known as the visible nulling coronagraph (VNC), that spans all four types of aperture and also employs differential sensing and control.

  5. The Revolution in Telescope Aperture C.M. Mountain and F.C. Gillett

    E-print Network

    ' The Revolution in Telescope Aperture C.M. Mountain and F.C. Gillett Gemini Observatory, 670 N. A that is often not recognised is the exponential growth in the total collecting area of large telescopes, materials and fabrication techniques ­­ these advances have facilitated the construction of telescopes

  6. Solar System Observing Capabilities With The James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Sonneborn, George; Milam, S. N.; Hines, D. C.; Stansberry, J.; Hammel, H. B.; Lunine, J. I.

    2013-10-01

    The James Webb Space Telescope (JWST) will provide breakthrough capabilities to study our Solar System. JWST is a large aperture, cryogenic, infrared-optimized space observatory under construction by NASA, ESA, and CSA for launch in 2018 into a L2 orbit. Imaging, spectroscopy, and coronography covers 0.6-29 microns. JWST is designed to observe Solar System objects having apparent rates of motion up to 0.030 arcseconds/second. This capability includes the planets, satellites, asteroids, Trans-Neptunian Objects, and comets beyond Earth’s orbit. JWST can observe solar elongation of 85 to 135 degrees, and a roll range of +/-5 degrees about the telescope’s optical axis. During the observation of a moving target, the science target is held fixed in the desired science aperture by controlling the guide star to follow the inverse of the target’s trajectory. The pointing control software uses polynomial ephemerides for the target generated using JPL’s HORIZON system. The JWST guider field of view (2.2x2.2 arcmin) is located in the telescope focal plane several arcmin from the science apertures. The instrument apertures are fixed with respect to the telescope focal plane. For targets near the ecliptic, those apertures also have a nearly-fixed orientation relative to the ecliptic. This resultsfrom the fact that the Observatory's sun-shade and solar panels must always be between the telescope and the Sun. On-board scripts autonomously control the execution of the JWST science timeline. The event-driven scripts respond to actual slew and on-board command execution, making operations more efficient. Visits are scheduled with overlapping windows to provide execution flexibility and to avoid lost time. An observing plan covering about ten days will be uplinked weekly. Updates could be more frequent if necessary (for example, to accommodate a Target of Opportunity - TOO). The event-driven operations system supports time-critical observations and TOOs. The minimum response time for TOOs is 48 hours (observation approval to execution).

  7. Conceptual design of an 18m aperture Multi-Mirror telescope

    Microsoft Academic Search

    B. Mack

    1984-01-01

    A conceptual development status assessment is made for the design of the British Multi-Mirror, 18-m effective aperture telescope, which has proceeded on the basis of experience gained in design and construction of the 4.2-m Altazimuth telescope. The Multi-Mirror telescope's translating mirrors yield a reduction in telescope structure costs, and the use of borosilicate glass honeycomb mirrors having high stiffness\\/weight ratios

  8. Parallel Image Reconstruction for New Vacuum Solar Telescope

    NASA Astrophysics Data System (ADS)

    Li, Xue-Bao; Wang, Feng; Xiang, Yong Yuan; Zheng, Yan Fang; Liu, Ying Bo; Deng, Hui; Ji, Kai Fan

    2014-04-01

    Many advanced ground-based solar telescopes improve the spatial resolution of observation images using an adaptive optics (AO) system. As any AO correction remains only partial, it is necessary to use post-processing image reconstruction techniques such as speckle masking or shift-and-add (SAA) to reconstruct a high-spatial-resolution image from atmospherically degraded solar images. In the New Vacuum Solar Telescope (NVST), the spatial resolution in solar images is improved by frame selection and SAA. In order to overcome the burden of massive speckle data processing, we investigate the possibility of using the speckle reconstruction program in a real-time application at the telescope site. The code has been written in the C programming language and optimized for parallel processing in a multi-processor environment. We analyze the scalability of the code to identify possible bottlenecks, and we conclude that the presented code is capable of being run in real-time reconstruction applications at NVST and future large aperture solar telescopes if care is taken that the multi-processor environment has low latencies between the computation nodes.

  9. Advanced Technology Large-Aperture Space Telescope (ATLAST) Appendix C: ATLAST-8m Design & Engineering Study

    E-print Network

    Sirianni, Marco

    & Engineering Study The ATLAST-8m engineering study was lead by NASA MFSC with guidance from the Space Telescope ! #12;ATLAST 8-m Design & Engineering Study 2 TABLE OF CONTENTS 1.0 ATLAST-8m Mission ConceptAdvanced Technology Large-Aperture Space Telescope (ATLAST) 1 Appendix C: ATLAST-8m Design

  10. Mirrors for solar telescopes made from ZERODUR glass ceramic

    Microsoft Academic Search

    Thorsten Döhring; Ralf Jedamzik; Peter Hartmann

    2007-01-01

    The zero expansion glass ceramic material, ZERODUR®, is well known for night-time telescope mirror substrates. Also for solar telescopes ZERODUR® is often selected as mirror blank material. Examples are the Swedish 1 m Solar Telescope (SST), the balloon-born telescope SUNRISE, and the New Solar Telescope (NST) of the Big Bear Solar Observatory. The properties of ZERODUR® are discussed with respect

  11. High Performance Lyot and PIAA Coronagraphy for Arbitrarily Shaped Telescope Apertures

    NASA Astrophysics Data System (ADS)

    Guyon, Olivier; Hinz, Philip M.; Cady, Eric; Belikov, Ruslan; Martinache, Frantz

    2014-01-01

    Two high-performance coronagraphic approaches compatible with segmented and obstructed telescope pupils are described. Both concepts use entrance pupil amplitude apodization and a combined phase and amplitude focal plane mask to achieve full coronagraphic extinction of an on-axis point source. While the first concept, called Apodized Pupil Complex Mask Lyot Coronagraph (APCMLC), relies on a transmission mask to perform the pupil apodization, the second concept, called Phase-Induced Amplitude Apodization complex mask coronagraph (PIAACMC), uses beam remapping for lossless apodization. Both concepts theoretically offer complete coronagraphic extinction (infinite contrast) of a point source in monochromatic light, with high throughput and sub-?/D inner working angle, regardless of aperture shape. The PIAACMC offers nearly 100% throughput and approaches the fundamental coronagraph performance limit imposed by first principles. The steps toward designing the coronagraphs for arbitrary apertures are described for monochromatic light. Designs for the APCMLC and the higher performance PIAACMC are shown for several monolith and segmented apertures, such as the apertures of the Subaru Telescope, Giant Magellan Telescope, Thirty Meter Telescope, the European Extremely Large Telescope, and the Large Binocular Telescope. Performance in broadband light is also quantified, suggesting that the monochromatic designs are suitable for use in up to 20% wide spectral bands for ground-based telescopes.

  12. High performance Lyot and PIAA coronagraphy for arbitrarily shaped telescope apertures

    SciTech Connect

    Guyon, Olivier; Hinz, Philip M. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Cady, Eric [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Belikov, Ruslan [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Martinache, Frantz, E-mail: guyon@naoj.org [National Astronomical Observatory of Japan, Subaru Telescope, Hilo, HI 96720 (United States)

    2014-01-10

    Two high-performance coronagraphic approaches compatible with segmented and obstructed telescope pupils are described. Both concepts use entrance pupil amplitude apodization and a combined phase and amplitude focal plane mask to achieve full coronagraphic extinction of an on-axis point source. While the first concept, called Apodized Pupil Complex Mask Lyot Coronagraph (APCMLC), relies on a transmission mask to perform the pupil apodization, the second concept, called Phase-Induced Amplitude Apodization complex mask coronagraph (PIAACMC), uses beam remapping for lossless apodization. Both concepts theoretically offer complete coronagraphic extinction (infinite contrast) of a point source in monochromatic light, with high throughput and sub-?/D inner working angle, regardless of aperture shape. The PIAACMC offers nearly 100% throughput and approaches the fundamental coronagraph performance limit imposed by first principles. The steps toward designing the coronagraphs for arbitrary apertures are described for monochromatic light. Designs for the APCMLC and the higher performance PIAACMC are shown for several monolith and segmented apertures, such as the apertures of the Subaru Telescope, Giant Magellan Telescope, Thirty Meter Telescope, the European Extremely Large Telescope, and the Large Binocular Telescope. Performance in broadband light is also quantified, suggesting that the monochromatic designs are suitable for use in up to 20% wide spectral bands for ground-based telescopes.

  13. Hubble Space Telescope solar array damper

    Microsoft Academic Search

    Joseph R. Maly; Scott C. Pendleton; J. Salmanoff; Garcia J. Blount; Kevin Mathews

    1999-01-01

    This paper describes the design of a solar array damper that will be built into each of two new solar arrays to be installed on the Hubble Space Telescope (HST) during Servicing Mission 3. On this mission, currently scheduled for August 2000, two 'rigid' solar array wings will replace the 'flexible' wings currently providing power for HST. In addition to

  14. Conceptual design of an 18m aperture Multi-Mirror telescope

    NASA Astrophysics Data System (ADS)

    Mack, B.

    1984-01-01

    A conceptual development status assessment is made for the design of the British Multi-Mirror, 18-m effective aperture telescope, which has proceeded on the basis of experience gained in design and construction of the 4.2-m Altazimuth telescope. The Multi-Mirror telescope's translating mirrors yield a reduction in telescope structure costs, and the use of borosilicate glass honeycomb mirrors having high stiffness/weight ratios furthers cost reductions by comparison with near-zero thermal expansion coefficient glass ceramics. The f/2 focal ratio allows for minimum tube structure lengths.

  15. Large-Aperture Mirror Array (LAMA): conceptual design for a distributed-aperture 42-meter telescope

    Microsoft Academic Search

    Paul Hickson; Kenneth M. Lanzetta

    2003-01-01

    We propose a high-density coherentarray of eighteen 10-meter liquid-mirror telescopes. Each telescope is equipped with a reflective corrector system that enables it to point and track within an eight-degree diameter accessible field of view centered on the zenith. Equipped with adaptive optics, each telescope would deliver a diffraction-limited beam to a common focal plane. There, a dichroic optical-infrared camera will

  16. Design of a telescope pointing and tracking subsystem for the Big Bear Solar Observatory New Solar Telescope

    E-print Network

    Design of a telescope pointing and tracking subsystem for the Big Bear Solar Observatory New Solar Telescope J. R. Varsika and G.Yangb aBig Bear Solar Observatory, 40386 North Shore Lane, Big Bear City Telescope at Big Bear Solar Observatory will use a distributed system to control the telescope, dome

  17. The Solar-B Solar Optical Telescope Focal Plane Package

    Microsoft Academic Search

    M. Levay; T. Berger; W. Rosenberg; T. Tarbell; T. Bogdan; D. Elmore; B. Lites

    1999-01-01

    The primary goal of the Solar-B mission is to understand the physical processes responsible for dynamics and heating of the outer solar atmosphere. The Focal Plane Package (FPP) instrument for the 50-cm Solar Optical Telescope provides precise measurements of the vector magnetic field, vertical and horizontal flows, and thermal conditions in the photosphere and low chromosphere with spatial resolution as

  18. 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.

  19. Detection and initial characterisation of an exoplanet atmosphere with small aperture telescopes

    NASA Astrophysics Data System (ADS)

    Bernt, I.; Müller, M.; Strassmeier, K. G.; Granzer, T.

    2013-09-01

    In the recent years atmospheres of exoplanets have been studied with space-based telescopes like the HST or large aperture ground-based telescopes like the Gran Telescopio Canarias. But as the number of suitable exoplanets is rising, comparative studies of atmospheres with a statistically meaningful amount of targets will follow, for which the observational time with large telescopes is limited and expensive. Our aim is to investigate whether it is possible to detect and initially characterise the atmosphere of an exoplanet with small aperture telescopes using chromatic variations in transit depths. We collected multi-color transits in the years 2011 to 2013 using the robotic 1.2m-telescope STELLA on Tenerife as well as the Nordic Optical Telescope and the 70cm-telescope at the Leibniz Institute for Astrophysics Potsdam. The highly inflated Hot Jupiter HAT-P-32 b was chosen as target for our pilot study for its favorable large atmospheric scale height and therefore enhanced atmospheric detectability. Models of the atmospheric spectra of HAT-P-32 b indicate that the STELLA-data can be used to distinguish between a dusty and a cloud-free atmosphere using the gradient in transit depth of the observations in the blue band and in the visible band. Here we want to present our project together with the first results of the transit depth analysis.

  20. 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 minimum atmosphere seeing at astronomical observatory site and exert the use efficiency of the telescope adequately. So the accuracy of the traditional surface of reflector can assure that 90% of all the light energy can be focused on within the angle diameter range of the minimum atmosphere seeing, then 100% of light energy should be focused on the angle diameter range of minimum atmosphere seeing. Because the rms of mirror is very high, precise surface machining and accurate the support of mirror are very important tasks during designing and manufacturing the telescope. In the paper, various support techniques of a large-aperture telescope primary mirror are discussed and a 3.5 meter telescope system at the Starfire Optical Range (SOR) overviewed simply, which was operated by the Directed Energy Directorate of the Air Force Research Laboratory, Kirtland AFB, NM, USA from the ground-based O-E system for the observations of spatial target. We also analyze Theoretical elastic deformation of the Steward Observatory 2.3 meter mirror is analyzed.

  1. 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.

  2. NLST: India's National Large Solar Telescope

    NASA Astrophysics Data System (ADS)

    Hasan, S. S.; Soltau, D.; Kärcher, H.; Süß, M.; Berkefeld, T.

    2010-06-01

    This article introduces the new Indian 2 m telescope which has been designed by MT Mechatronics in a detailed conceptual design study for the Indian Institute of Astrophysics, Bangalore. We describe the background of the project and the science goals which shall be addressed with this telescope. NLST is a solar telescope with high optical throughput and will be equipped with an integrated Adaptive Optics system. It is optimized for a site with the kind of seeing and wind conditions as they are expected at a lake site in the Himalayan mountains. The telescope can also be used for certain night time applications. We also give the scientific rationale for this class of telescope.

  3. Mirrors for solar telescopes made from ZERODUR glass ceramic

    NASA Astrophysics Data System (ADS)

    Döhring, Thorsten; Jedamzik, Ralf; Hartmann, Peter

    2007-09-01

    The zero expansion glass ceramic material, ZERODUR®, is well known for night-time telescope mirror substrates. Also for solar telescopes ZERODUR® is often selected as mirror blank material. Examples are the Swedish 1 m Solar Telescope (SST), the balloon-born telescope SUNRISE, and the New Solar Telescope (NST) of the Big Bear Solar Observatory. The properties of ZERODUR® are discussed with respect to the special technical requirements of solar observatories, resulting in the conclusion that mirrors made of this glass ceramic material are an excellent choice for solar telescopes.

  4. FAST - Five hundred meter Aperture Spherical radio Telescope

    NASA Astrophysics Data System (ADS)

    Nan, Ren-Dong

    2009-01-01

    The idea of sitting a large spherical dish in Karst depression is rooted in Arecibo telescope hosted by the NAIC of Cornell University. FAST is an Arecibo-type antenna with 3 outstanding aspects: the unique karst depression as the site; the active main reflector which corrects spherical aberration on the ground to achieve full polarization and wide band without involving complex feed system; and the light focus cabin driven by cables and servomechanism plus a parallel robot as secondary adjustable system to carry the most precise parts of the receivers. These design features will enable FAST to jumpstart many of science goals, such as HI neutral hydrogen line survey, pulsar survey, largest station in VLBI network, spectral line observations and Search for alien's technologies. The feasibility studies for FAST have been carried out for 14 years, being supported by Chinese and world astronomical communities. Funding for Project FAST has been approved by the National Development and Reform commission NDRC in July of 2007 with a capital budget 600 millions RMB and a project time of 5.5 years from the foundation. The first light is expected to be in early 2014. This work is supported by the Chinese Academy of Sciences and the National Natural Science Foundation of China (Grant No. 10433020). More than a hundred research personnel from over thirty research teams were involved in this research. On behalf of project FAST, I wish to make special recognition to their diligent work and great contribution to the project.

  5. A 16-m Telescope for the Advanced Technology Large Aperture Telescope (ATLAST) Mission

    NASA Astrophysics Data System (ADS)

    Lillie, Charles F.; Dailey, D. R.; Polidan, R. S.

    2010-01-01

    Future space observatories will require increasingly large telescopes to study the earliest stars and galaxies, as well as faint nearby objects. Technologies now under development will enable telescopes much larger than the 6.5-meter diameter James Webb Space Telescope (JWST) to be developed at comparable costs. Current segmented mirror and deployable optics technology enables the 6.5 meter JWST telescope to be folded for launch in the 5-meter diameter Ariane 5 payload fairing, and deployed autonomously after reaching orbit. Late in the next decade, when the Ares V Cargo Launch Vehicle payload fairing becomes operational, even larger telescope can be placed in orbit. In this paper we present our concept for a 16-meter JWST derivative, chord-fold telescope which could be stowed in the 10-m diameter Ares V fairing, plus a description of the new technologies that enable ATLAST to be developed at an affordable price.

  6. 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.

  7. Engineering Specification for Large-aperture UVO Space Telescopes Derived from Science Requirements

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Arnold, William; Bevan, Ryan M.; Smith, W. Scott.; Kirk, Charles S.; Postman, Mark

    2013-01-01

    An advanced large aperture UV/optical UVO space telescope is required for the next generation of astrophysics and exoplanet science. The science requirements of proposed exoplanet and astrophysics missions were used to determine the encircled energy, point spread function stability and thermal environment requirements. These requirements then determine the optical wavefront specification for potential telescope assemblies which can fit inside current and planned launch vehicles. The optical wavefront specification becomes the top level of the error budget that is split into various sources that control the structural, thermal and optical design.

  8. Solar Magnetism and the Activity Telescope at HSOS

    NASA Astrophysics Data System (ADS)

    Zhang, Hong-Qi; Wang, Dong-Guang; Deng, Yuan-Yong; Hu, Ke-Liang; Su, Jiang-Tao; Lin, Jia-Ben; Lin, Gang-Hua; Yang, Shi-Mo; Mao, Wei-Jun; Wang, Ya-Nan; Hu, Qi-Qian; Xue, Jun-Sun; Lu, Hai-Tian; Ni, Hou-Kun; Chen, Han-Liang; Zhou, Xiao-Jun; Zhu, Qing-Sheng; Yuan, Lü-Jun; Zhu, Yong

    2007-04-01

    A new solar telescope system is described, which has been operating at Huairou Solar Observing Station (HSOS), National Astronomical Observatories, Chinese Academy of Sciences (CAS), since the end of 2005. This instrument, the Solar Magnetism and Activity Telescope (SMAT), comprises two telescopes which respectively make measurements of full solar disk vector magnetic field and H? observation. The core of the full solar disk video vector magnetograph is a birefringent filter with 0.1Ĺ bandpass, installed in the tele-centric optical system of the telescope. We present some preliminary observational results of the full solar disk vector magnetograms and H? filtergrams obtained with this telescope system.

  9. 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.

  10. 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.

  11. Cornell Caltech Atacama Telescope (CCAT): a 25 m aperture telescope above 5000 m altitude

    E-print Network

    Thomas A. Sebring; Riccardo Giovanelli; Simon Radford; Jonas Zmuidzinas

    2006-10-17

    Cornell, California Institute of Technology (Caltech), and Jet Propulsion Lab (JPL) have joined together to study development of a 25 meter sub-millimeter telescope (CCAT) on a high peak in the Atacama region of northern Chile, where the atmosphere is so dry as to permit observation at wavelengths as short as 200 micron. The telescope is designed to deliver high efficiency images at that wavelength with a total 1/2 wavefront error of about 10 microns. With a 20 arc min field of view, CCAT will be able to accommodate large format bolometer arrays and will excel at carrying out surveys as well as resolving structures to the 2 arc sec. resolution level. The telescope will be an ideal complement to ALMA. Initial instrumentation will include both a wide field bolometer camera and a medium resolution spectrograph. Studies of the major telescope subsystems have been performed as part of an initial Feasibility Concept Study. Novel aspects of the telescope design include kinematic mounting and active positioning of primary mirror segments, high bandwidth secondary mirror segment motion control for chopping, a Calotte style dome of 50 meter diameter, a mount capable of efficient scanning modes of operation, and some new approaches to panel manufacture. Analysis of telescope performance and of key subsystems will be presented to illustrate the technical feasibility and pragmatic cost of CCAT. Project plans include an Engineering Concept Design phase followed by detailed design and development. First Light is planned for early 2012.

  12. Review of the Solar Array Telescopes

    E-print Network

    David A. Smith

    2006-08-11

    For several years the only experiments sensitive to astrophysical gamma rays with energies beyond the reach of EGRET but below that of the Cherenkov imaging telescopes have been the "solar tower" detectors. They use >2000 m2 mirror areas to sample the Cherenkov wavefront generated by <100 GeV gamma rays, obtaining Crab sensitivities of more than 6$\\sigma$ in one ON-source hour. I will review the history of the solar tower Cherenkov experiments from 1992 to the present and their key design features. I will describe some successful analysis strategies, then summarize the principal results obtained.

  13. ExSPO: A Discovery Class Apodized Square Aperture (ASA) Expo-Planet Imaging Space Telescope Concept

    NASA Technical Reports Server (NTRS)

    Gezari, D.; Harwit, M.; Lyon, R.; Melnick, G.; Papaliolos, G.; Ridgeway, S.; Woodruff, R.; Nisenson, P.; Oegerle, William (Technical Monitor)

    2002-01-01

    ExSPO is a Discovery Class (approx. 4 meter) apodized square aperture (ASA) space telescope mission designed for direct imaging of extrasolar Earth-like planets, as a precursor to TPF. The ASA telescope concept, instrument design, capabilities, mission plan and science goals are described.

  14. 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.

  15. Innovative enclosure dome/observing aperture system design for the MROI Array Telescopes

    NASA Astrophysics Data System (ADS)

    Busatta, A.; Marchiori, G.; Mian, S.; Payne, I.; Pozzobon, M.

    2010-07-01

    The close-pack array of the MROI necessitated an original design for the Unit Telescope Enclosure (UTE) at Magdalena Ridge Observatory. The Magdalena Ridge Observatory Interferometer (MROI) is a project which comprises an array of up to ten (10) 1.4m diameter mirror telescopes arranged in a "Y" configuration. Each of these telescopes will be housed inside a Unit Telescope Enclosure (UTE) which are relocatable onto any of 28 stations. The most compact configuration includes all ten telescopes, several of which are at a relative distance of less than 8m center to center from each other. Since the minimum angle of the field of regard is 30° with respect to the horizon, it is difficult to prevent optical blockage caused by adjacent UTEs in this compact array. This paper presents the design constraints inherent in meeting the requirement for the close-pack array. An innovative design enclosure was created which incorporates an unique dome/observing aperture system. The description of this system focuses on how the field of regard requirement led to an unique and highly innovative concept that had to be able to operate in the harsh environmental conditions encountered at an altitude of 10,460ft (3,188m). Finally, we describe the wide use of composites materials and structures (e.g. glass/carbon fibres, sandwich panels etc.) on the aperture system which represents the only way to guarantee adequate thermal and environmental protection, compactness, structural stability and limited power consumption due to reduced mass.

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

    NASA Astrophysics Data System (ADS)

    Oegerle, William R.; Feinberg, L.; Purves, L.; Hyde, T.; Thronson, H.; Townsend, J.; Postman, M.; Bolcar, M.; Budinoff, J.; Dean, B.; Clampin, M.; 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 1.315m 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.

  17. Imaging M15 with a Small Aperture Telescope by Treating the Core as a Single Star

    NASA Astrophysics Data System (ADS)

    Howe, Rodney; Iakovos-Marios, Strikis

    2011-05-01

    The objective for this study will be to explore various time series methods using CCD photometry for use with amateur telescope observations of the dense globular cluster M15. Amateur telescopes are defined here as having an aperture of less than 40 cm, and are collecting photometric filtered observations over time. Specifically, we attempt to determine the light curve of the core of M15 as a "single star". This requires selection of comparison and check stars to perform differential photometry; i.e. subtraction of flux density measures between a nonvariable (reference star) and the variable "single star" of the M15 core as it changes in magnitudes over time. We explore the possibility of measuring the M15 periodicity as an aggregate of many standard stars as identified in the Stetson catalog for NGC7078 (2010). In this paper we'd like to propose methods and techniques for aggregating different cluster region's flux densities (luminosity) and periods.

  18. The Advanced Technology Solar Telescope enclosure

    NASA Astrophysics Data System (ADS)

    Phelps, L.; Barr, J.; Dalrymple, N.; Fraser, M.; Hubbard, R.; Wagner, J.; Warner, M.

    2006-06-01

    Telescope enclosure design is based on an increasingly standard set of criteria. Enclosures must provide failsafe protection in a harsh environment for an irreplaceable piece of equipment; must allow effective air flushing to minimize local seeing while still attenuating wind-induced vibration of the telescope; must reliably operate so that the dome is never the reason for observatory down time; must provide access to utilities, lifting devices and support facilities; and they must be affordable within the overall project budget. The enclosure for the Advanced Technology Solar Telescope (ATST) has to satisfy all these challenging requirements plus one more. To eliminate so-called external dome seeing, the exterior surfaces of the enclosure must be maintained at or just below ambient air temperature while being subjected to the full solar loading of an observing day. Further complicating the design of the ATST enclosure and support facilities are the environmental sensitivities and high construction costs at the selected site - the summit of Haleakala on the island of Maui, Hawaii. Previous development work has determined an appropriate enclosure shape to minimize solar exposure while allowing effective interior flushing, and has demonstrated the feasibility of controlling the exterior skin temperature with an active cooling system. This paper presents the evolution of the design since site selection and how the enclosure and associated thermal systems have been tailored to the particular climatic and terrain conditions of the site. Also discussed are load-reduction strategies that have been identified through thermal modeling, CFD modeling, and other analyses to refine and economize the thermal control systems.

  19. Ray-tracing and physical-optics analysis of the aperture efficiency in a radio telescope.

    PubMed

    Olmi, Luca; Bolli, Pietro

    2007-07-01

    The performance of telescope systems working at microwave or visible-IR wavelengths is typically described in terms of different parameters according to the wavelength range. Most commercial ray-tracing packages have been specifically designed for use with visible-IR systems and thus, though very flexible and sophisticated, do not provide the appropriate parameters to fully describe microwave antennas and to compare with specifications. We demonstrate that the Strehl ratio is equal to the phase efficiency when the apodization factor is taken into account. The phase efficiency is the most critical contribution to the aperture efficiency of an antenna and the most difficult parameter to optimize during the telescope design. The equivalence between the Strehl ratio and the phase efficiency gives the designer/user of the telescope the opportunity to use the faster commercial ray-tracing software to optimize the design. We also discuss the results of several tests performed to check the validity of this relationship that we carried out using a ray-tracing software, ZEMAX, and a full Physical Optics software, GRASP9.3, applied to three different telescope designs that span a factor of approximately 10 in terms of D/lambda. The maximum measured discrepancy between phase efficiency and Strehl ratio varies between approximately 0.4% and 1.9% up to an offset angle of >40 beams, depending on the optical configuration, but it is always less than 0.5% where the Strehl ratio is >0.95. PMID:17571151

  20. Layer-oriented adaptive optics for solar telescopes

    E-print Network

    Kellerer, Aglae

    2012-01-01

    First multi-conjugate 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" in diameter. We propose to implement the layer-oriented approach in solar MCAO 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, that only need to account for local turbulence: the sub-apertures 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 benefit...

  1. Moon Dust Telescopes, Solar Concentrators, and Structures

    NASA Astrophysics Data System (ADS)

    Chen, Peter C.; Van Steenberg, M. E.; Oliversen, R. J.

    2008-05-01

    We report development of an ISRU (in situ resource utilization) process to fabricate large telescope mirrors, solar concentrators, and structures on the Moon. The Moon is an excellent site for a future space base and space astrophysics research. However transporting extremely large (10-50m) telescopes to the Moon, building up an observatory structure, and providing power for operation face the obstacles of high cost and logistical difficulties. We suggest a simple and novel approach to the problem. Large mirrors can be made by spincasting a liquid over or mixed with lunar surface soil (regolith). The liquid, which is a special vacuum stable cryogenic polymer, gradually solidifies while spun into a hard parabolic surface. Additives including carbon nanotubes and fibers can be used to increase tensile strength, reduce cure shrinkage, and enhance thermal conductivity. The process uses a single apparatus to make multiple mirrors. Large arrays of solar concentrators can be fabricated to provide power to a lunar base. For astronomy, the mirror surface can be polished or modified in situ with an ion beam like process taking advantage of the high vacuum of the lunar environment. Moreover, we have found that the simple process of mixing a small amount of polymer with lunar regolith yields after curing a material similar to cement in terms of strength, density, and consistency. This `lunar cement’ may be useful as building blocks for human habitats and telescope structures. We report on experiments carried out at GSFC to demonstrate feasibility of the concept. Mirrors and bricks have been made by curing a cryogenic polymer with added JSC-1A Fine lunar soil simulant and carbon nanotubes. Preliminary observations have been carried out using such `Moon dust’ mirrors.

  2. Results of aperture area comparisons for exo-atmospheric total solar irradiance measurements.

    PubMed

    Johnson, B Carol; Litorja, Maritoni; Fowler, Joel B; Shirley, Eric L; Barnes, Robert A; Butler, James J

    2013-11-20

    Exo-atmospheric solar irradiance measurements made by the solar irradiance community since 1978 have incorporated limiting apertures with diameters measured by a number of metrology laboratories using a variety of techniques. Knowledge of the aperture area is a critical component in the conversion of radiant flux measurements to solar irradiance. A National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) sponsored international comparison of aperture area measurements of limiting apertures provided by solar irradiance researchers was performed, the effort being executed by the National Institute of Standards and Technology (NIST) in coordination with the EOS Project Science Office. Apertures that had institutional heritage with historical solar irradiance measurements were measured using the absolute aperture measurement facility at NIST. The measurement technique employed noncontact video microscopy using high-accuracy translation stages. We have quantified the differences between the participating institutions' aperture area measurements and find no evidence to support the hypothesis that preflight aperture area measurements were the root cause of discrepancies in long-term total solar irradiance satellite measurements. Another result is the assessment of uncertainties assigned to methods used by participants. We find that uncertainties assigned to a participant's values may be underestimated. PMID:24513747

  3. 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. Phillip; 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.

  4. Star sensors of the Space Solar Telescope

    NASA Astrophysics Data System (ADS)

    Sun, Caihong; Ai, Guoxiang; Jin, Shengzhen; Zhu, Zheng; Guo, Ruiying

    2000-10-01

    The Space Solar Telescope (SST) is being developed in Beijing Astronomical Observatory. Two sets of star sensors are needed to fit the requirement of high accuracy attitude determination of SST. The Attitude Determination and Control System (ADCS) of SST is narrated in this paper. How to mount and use the Star Sensors on SST is introduced. The structure of the data handling system and the features such as the precision, field of view (FOV), mass and power consumption of the Star Sensor are given. To elevate accuracy affected by designing and manufacturing of optical lens, mechanical and electrical parts, a calibration correction should be applied. The development of algorithms based on 'triangle set' for the recognition of star patterns, especially the consideration of preventing SST from 'lost in space' is discussed too. The altitude of SST is calculated by the valid data of the Star Sensors and the Sun Guide Telescope. The test results shows that the Star Sensor researched and developed by us can be used not only for SST, but also for other satellites.

  5. 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. PMID:25608076

  6. Progress Report on a Feasibility Study of a Large Optical/Infrared Solar Telescope (CLEAR)

    NASA Astrophysics Data System (ADS)

    Beckers, Jacques M.; NSO Staff

    With the end of the US participation in LEST, the question of the development of modern, large, ground-based facilities to satisfy the research needs of solar physics in the USA is open. Large telescopes are needed to answer many important science issues. Among these are (i) high angular resolution needed to resolve the scales at which most of the action is in solar magneto-hydrodynamics (ii) access to the infrared part of the solar spectrum wanted to extend the range over physical conditions over which the solar atmosphere is studied (iii) accurate polarization observations needed to measure solar magnetic fields, (iv) high sensitivities, essential to study variations in these and other solar conditions, and (v) coronagraphic capability to observe magnetic fields and small scale structures in the solar corona. CLEAR (Coronagraph and Low Emissivity Astronomical Reflector) is a concept that attempts to combine these qualities in one telescope, 2 to 4 meter in aperture, without compromising the solar science goals. This is a status report on the on-going feasibility study of CLEAR that addresses both technical and budgetary issues. A site survey is being conducted among existing solar sites to identify the optimum location.

  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. 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.

  9. 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.

  10. 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.

  11. High-flux, high-temperature thermal vacuum qualification testing of a solar receiver aperture shield

    Microsoft Academic Search

    Thomas W. Kerslake; Lee S. Mason; Hal J. Strumpf

    1997-01-01

    To verify its thermal-structural durability under anticipated high-flux, high-temperature loading, a solar dynamic power system receiver aperture shield test article was constructed and underwent a series of two tests in a large thermal vacuum chamber configured with a reflective, point-focus solar concentrator and a solar simulator. The test article was positioned near the focal plane and exposed to concentrated solar

  12. Extreme adaptive optics imaging with a clear and well-corrected off-axis telescope sub-aperture

    E-print Network

    E. Serabyn; K. Wallace; M. Troy; B. Mennesson; P. Haguenauer; R. Gappinger; R. Burruss

    2007-02-21

    Rather than using an adaptive optics (AO) system to correct a telescope s entire pupil, it can instead be used to more finely correct a smaller sub-aperture. Indeed, existing AO systems can be used to correct a sub-aperture 1/3 to 1/2 the size of a 5-10 m telescope to extreme adaptive optics (ExAO) levels. We discuss the potential performance of a clear off-axis well-corrected sub-aperture (WCS), and describe our initial imaging results with a 1.5 m diameter WCS on the Palomar Observatory s Hale telescope. These include measured Strehl ratios of 0.92-0.94 in the infrared (2.17 microns), and 0.12 in the B band, the latter allowing a binary of separation 0.34 arc sec to be easily resolved in the blue. Such performance levels enable a variety of novel observational modes, such as infrared ExAO, visible-wavelength AO, and high-contrast coronagraphy. One specific application suggested by the high Strehl ratio stability obtained (1%) is the measurement of planetary transits and eclipses. Also described is a simple dark-hole experiment carried out on a binary star, in which a comatic phase term was applied directly to the deformable mirror, in order to shift the diffraction rings to one side of the point spread function.

  13. Defining A Risk Analysis Strategy for Exo-Earth Yields from a Future Large Aperture UVOIR Space Telescope

    NASA Astrophysics Data System (ADS)

    Mandell, Avi; Stark, Christopher C.; Roberge, Aki; Domagal-Goldman, Shawn; Stapelfeldt, Karl R.; Robinson, Tyler

    2015-01-01

    The discovery and characterization of Earth-like planets around Sun-like stars using high-contrast imaging is a critical science metric for constraining the requirements on the next-generation large UVOIR space telescope. The dominant driver for the observatory architecture, cost and schedule is the telescope aperture size. Therefore it is important to provide as much constraint as possible on the required aperture size early in the design and planning process.An estimate of the detection yield for Earth-like planets can be calculated using a Monte Carlo simulation of a design reference mission (DRM), allowing the exploration of a variety of mission design and astrophysical parameters. We have developed such a code (Stark et al. 2014); it optimizes the target list and exposure times to maximize mission yield for a specific set of mission parameters. However, many of the important astrophysical quantities and future technical capabilities that feed into these parameters are not well constrained. This leads to a large uncertainty in the final mission architecture needed to achieve a specific exo-Earth yield.In this presentation we discuss the various physical and technological parameters that go into the DRM simulations, and the associated uncertainties based on the current state of research. We then present a strategy for a three-tiered risk assessment using these uncertainties, and conclude with a discussion of the current range in telescope aperture size associated with each risk level.

  14. Integrating Seeing Measurements into the Operations of Solar Telescopes

    E-print Network

    ). The observatory is situated on a small peninsula in Big Bear Lake, a mountain lake at an altitude of about 2100 m in the San Bernardino Mountains of Southern California. The lake effectively suppresses the boundary layer by the site survey for the Advanced Technology Solar Telescope (ATST) as one of the best sites for solar

  15. Development of new solar radio telescope in NICT

    NASA Astrophysics Data System (ADS)

    Kubo, Yuki; Watari, Shinichi; Ishii, Mamoru; Ishibashi, Hiromitsu; Iwai, Kazumasa

    Solar radio burst is one of the most important events for not only space weather forecasting but also investigating high-energy phenomena in solar corona. The GHz solar radio waves are synchrotron radiation emitted by high energy electrons at lower corona. On the other hand, the MHz solar radio bursts, especially type II and III bursts, are radiated via mode conversion of Langmuir waves excited by high energy electrons. These high energy electrons are accelerated at reconnection regions in solar flare and shock waves in solar corona. Therefore, MHz and GHz solar radio waves are closely related each other through the accelerated high energy electrons. So, wide frequency range (MHz to GHz) radio wave observations with high time resolution are required to comprehensively understand high energy phenomena in solar corona. We have been operating solar radio spectrograph called HiRAS for over twenty years in Hiraiso Solar Observatory, National Institute of Information and Communications Technology (NICT), but the system has been decrepit and radio wave environment in Hiraiso is getting worse. So, we have developed a new solar radio telescope in Yamagawa radio observation facility, NICT. The frequency range and time resolution in the system is 70MHz to 9.0GHz and 8 msec. In this presentation, we introduce status in progress for our new solar radio telescope.

  16. Imaging power of multi-fibered nulling telescopes for extra-solar planet characterization

    NASA Astrophysics Data System (ADS)

    Hénault, François

    2011-10-01

    In this paper are discussed the nulling and imaging properties of monolithic pupil telescopes equipped with a focal plane waveguide array, which could be envisaged as precursor space missions for future nulling interferometers or coronagraphs searching for habitable planets outside of our solar system. Three different concepts of nulling telescopes are reviewed, namely the Super-Resolving Telescope (SRT) having multiple, non-overlapping exit sub-apertures and the Sheared-Pupil Telescope (SPT), either unmasked or masked with a Lyot stop placed at its exit pupil plane. For each case simple theoretical relationships allowing to estimate the nulling rate, Signal-to-Noise Ratio (SNR) and Inner Working Angle (IWA) of the telescope are established or recalled, and numerical simulations are conducted. The preliminary results of this study show that the most promising designs should either be a SRT of high radiometric efficiency associated with an adequate leakage calibration procedure, or a masked SPT with potentially deeper nulling rates but lower SNR, depending on what kind of performance is to be preferred.

  17. Current concept for the 4m European Solar Telescope (EST) optical design

    Microsoft Academic Search

    J. Sánchez Capuchino; M. Collados; D. Soltau; R. López; J. L. Rasilla; B. Gelly

    2010-01-01

    The European Solar Telescope (EST) is a 4-m class solar telescope to be located in the Canary Islands which is currently in its conceptual design study. EST is a pan-european project (with 29 partners, plus 7 collaborating institutions, from 14 countries) promoted by the European Association for Solar Telescopes (EAST). In the current concept, the main telescope and its transfer

  18. Current concept for the 4m European Solar Telescope (EST) optical design

    Microsoft Academic Search

    J. Sánchez-Capuchino; M. Collados; D. Soltau; R. López; J. L. Rasilla; B. Gelly

    2010-01-01

    The European Solar Telescope (EST) is a pan-european project (with 29 partners, plus 7 collaborating institutions, from 14 countries) for the conceptual design study of a 4-meter class solar telescope promoted by the European Association for Solar Telescopes (EAST) to be located in the Canary Islands. The telescope, in the conceptual study, provides a Coudé focus with an F\\/50 telecentric

  19. Design and Analysis of the Aperture Shield Assembly for a Space Solar Receiver

    NASA Technical Reports Server (NTRS)

    Strumpf, Hal J.; Trinh, Tuan; Westelaken, William; Krystkowiak, Christopher; Avanessian, Vahe; Kerslake, Thomas W.

    1997-01-01

    A joint U.S./Russia program has been conducted to design, develop, fabricate, launch, and operate the world's first space solar dynamic power system on the Russian Space Station Mir. The goal of the program was to demonstrate and confirm that solar dynamic power systems are viable for future space applications such as the International Space Station (ISS). The major components of the system include a solar receiver, a closed Brayton cycle power conversion unit, a power conditioning and control unit, a solar concentrator, a radiator, a thermal control system, and a Space Shuttle carrier. Unfortunately, the mission was demanifested from the ISS Phase 1 Space Shuttle Program in 1996. However, NASA Lewis is proposing to use the fabricated flight hardware as part of an all-American flight demonstration on the ISS in 2002. The present paper concerns the design and analysis of the solar receiver aperture shield assembly. The aperture shield assembly comprises the front face of the cylindrical receiver and is located at the focal plane of the solar concentrator. The aperture shield assembly is a critical component that protects the solar receiver structure from highly concentrated solar fluxes during concentrator off-pointing events. A full-size aperture shield assembly was fabricated. This unit was essentially identical to the flight configuration, with the exception of materials substitution. In addition, a thermal shock test aperture shield assembly was fabricated. This test article utilized the flight materials and was used for high-flux testing in the solar simulator test rig at NASA Lewis. This testing is described in a companion paper.

  20. Design and analysis of the aperture shield assembly for space solar receiver

    SciTech Connect

    Strumpf, H.J.; Trinh, T.; Westelaken, W.; Krystkowiak, C.; Avanessian, V. [AlliedSignal Aerospace Equipment Systems, Torrance, CA (United States); Kerslake, T.W. [NASA Lewis Research Center, Cleveland, OH (United States)

    1997-12-31

    A joint US/Russia program has been conducted to design, develop, fabricate, launch, and operate the world`s first space solar dynamic power system on the Russian Space Station Mir. The goal of the program was to demonstrate and confirm that solar dynamic power systems are viable for future space applications such as the International Space Station (ISS). The major components of the system include a solar receiver, a closed Brayton cycle power conversion unit, a power conditioning and control unit, a solar concentrator, a radiator, a thermal control system, and a Space Shuttle carrier. Unfortunately, the mission was demanifested from the ISS Phase 1 Space Shuttle Program in 1996. However, NASA Lewis is proposing to use the fabricated flight hardware as part of an all-American flight demonstration on the ISS in 2002. The present paper concerns the design and analysis of the solar receiver aperture shield assembly. The aperture shield assembly comprises the front face of the cylindrical receiver and is located at the focal plane of the solar concentrator. The aperture shield assembly is a critical component that protects the solar receiver structure from highly concentrated solar fluxes during concentrator off-pointing events. A full-size aperture shield assembly was fabricated. This unit was essentially identical to the flight configuration, with the exception of materials substitution. In addition, a thermal shock test aperture shield assembly was fabricated. This test article utilized the flight materials and was used for high-flux testing in the solar simulator test rig at NASA Lewis. This testing is described in a companion paper.

  1. SLGLAO: An all-sky, wide field adaptive optics system for large aperture telescopes

    Microsoft Academic Search

    M. C. Britton; K. Taylor

    2004-01-01

    This paper describes an adaptive optics concept that uses a single sodium laser beacon driving a single deformable mirror to achieve partial compensation of atmospheric turbulence over a relatively wide field of view. The angular size of the corrected field of view increases with aperture diameter, while the degree of partial compensation decreases with aperture diameter. For a 30 meter

  2. The James Webb Space Telescope: Solar System Science

    NASA Astrophysics Data System (ADS)

    Hines, Dean C.; Hammel, H. B.; Lunine, J. I.; Milam, S. N.; Kalirai, J. S.; Sonneborn, G.

    2013-01-01

    The James Webb Space Telescope (JWST) is poised to revolutionize many areas of astrophysical research including Solar System Science. Scheduled for launch in 2018, JWST is ~100 times more powerful than the Hubble and Spitzer observatories. It has greater sensitivity, higher spatial resolution in the infrared, and significantly higher spectral resolution in the mid infrared. Imaging and spectroscopy (both long-slit and integral-field) will be available across the entire 0.6 - 28.5 micron wavelength range. Herein, we discuss the capabilities of the four science instruments with a focus on Solar System Science, including instrument modes that enable observations over the huge range of brightness presented by objects within the Solar System. The telescope is being built by Northrop Grumman Aerospace Systems for NASA, ESA, and CSA. JWST development is led by NASA's Goddard Space Flight Center. The Space Telescope Science Institute (STScI) is the Science and Operations Center (S&OC) for JWST.

  3. Prospects for the CERN Axion Solar Telescope Sensitivity to 14.4 keV Axions

    E-print Network

    Kresimir Jakovcic; for the CAST Collaboration

    2006-11-15

    The CERN Axion Solar Telescope (CAST) is searching for solar axions using the 9.0 T strong and 9.26 m long transverse magnetic field of a twin aperture LHC test magnet, where axions could be converted into X-rays via reverse Primakoff process. Here we explore the potential of CAST to search for 14.4 keV axions that could be emitted from the Sun in M1 nuclear transition between the first, thermally excited state, and the ground state of 57Fe nuclide. Calculations of the expected signals, with respect to the axion-photon coupling, axion-nucleon coupling and axion mass, are presented in comparison with the experimental sensitivity.

  4. A New Debris Detection Algorithm for Orbiting Solar Telescopes

    Microsoft Academic Search

    C. De Santis; A. Bigazzi; F. Berrilli; M. Casolino; D. Del Moro; P. Picozza; R. Sparvoli; Tor Vergata

    As part of the Phase-A feasibility study for a new Solar Mission, ADAHELI, financed by the Italian Space Agency, an algorithm for detecting debris using images produced by the on-board solar telescope, has been developed. ESA's GSTP-5 ELEMENT 3 provisions, for activities related to Space Situational Awareness, identify optical systems as key elements for monitoring orbiting objects. So far, only

  5. High-Flux, High-Temperature Thermal Vacuum Qualification Testing of a Solar Receiver Aperture Shield

    NASA Technical Reports Server (NTRS)

    Kerslake, Thomas W.; Mason, Lee S.; Strumpf, Hal J.

    1997-01-01

    As part of the International Space Station (ISS) Phase 1 program, NASA Lewis Research Center (LERC) and the Russian Space Agency (RSA) teamed together to design, build and flight test the world's first orbital Solar Dynamic Power System (SDPS) on the Russian space station Mir. The Solar Dynamic Flight Demonstration (SDFD) program was to operate a nominal 2 kWe SDPS on Mir for a period up to 1-year starting in late 1997. Unfortunately, the SDFD mission was demanifested from the ISS phase 1 shuttle program in early 1996. However, substantial flight hardware and prototypical flight hardware was built including a heat receiver and aperture shield. The aperture shield comprises the front face of the cylindrical cavity heat receiver and is located at the focal plane of the solar concentrator. It is constructed of a stainless steel plate with a 1-m outside diameter, a 0.24-m inside diameter and covered with high-temperature, refractory metal Multi-Foil Insulation (MFI). The aperture shield must minimize heat loss from the receiver cavity, provide a stiff, high strength structure to accommodate shuttle launch loads and protect receiver structures from highly concentrated solar fluxes during concentrator off-pointing events. To satisfy Mir operational safety protocols, the aperture shield was required to accommodate direct impingement of the intensely concentrated solar image for a 1-hour period. To verify thermal-structural durability under the anticipated high-flux, high-temperature loading, an aperture shield test article was constructed and underwent a series of two tests in a large thermal vacuum chamber configured with a reflective, point-focus solar concentrator and a solar simulator. The test article was positioned near the focal plane and exposed to concentrated solar flux for a period of 1-hour. In the first test, a near equilibrium temperature of 1862 K was attained in the center of the shield hot spot. In the second test, with increased incident flux, a near equilibrium temperature of 2072 K was achieved. The aperture shield sustained no visible damage as a result of the exposures. This paper describes the aperture shield thermal-vacuum qualification test program including the test article, test facility, procedures, data collection, test success criteria, results and conclusions.

  6. High-flux, high-temperature thermal vacuum qualification testing of a solar receiver aperture shield

    SciTech Connect

    Kerslake, T.W.; Mason, L.S. [NASA Lewis Research Center, Cleveland, OH (United States); Strumpf, H.J. [AlliedSignal Aerospace Equipment Systems, Torrance, CA (United States)

    1997-12-31

    As part of the International Space Station (ISS) Phase 1 program, NASA Lewis Research Center (LeRC) and the Russian Space Agency (RSA) teamed together to design, build and flight test the world`s first orbital Solar Dynamic Power System (SDPS) on the Russian space station Mir. The Solar Dynamic Flight Demonstration (SDFD) program was to operate a nominal 2 kWe SDPS on Mir for a period up to 1-year starting in late 1997. Unfortunately, the SDFD mission was demanifested from the ISS Phase 1 shuttle program in early 1996. However, substantial flight hardware and prototypical flight hardware was built including a heat receiver and aperture shield. The aperture shield comprises the front face of the cylindrical cavity heat receiver and is located at the focal plane of the solar concentrator. It is constructed of a stainless steel plate with a 1-m outside diameter, a 0.24-m inside diameter and covered with high-temperature, refractory metal multi-foil insulation (MFI). The aperture shield must minimize heat loss from the receiver cavity, provide a stiff, high strength structure to accommodate shuttle launch loads and protect receiver structures from highly concentrated solar fluxes during concentrator off-pointing events. To satisfy Mir operational safety protocols, the aperture shield was required to accommodate direct impingement of the intensely concentrated solar image for a 1-hour period. To verify thermal-structural durability under the anticipated high-flux, high-temperature loading, an aperture shield test article was constructed and underwent a series of two tests in a large thermal vacuum chamber configured with a reflective, point-focus solar concentrator and a solar simulator. The test article was positioned near the focal plane and exposed to concentrated solar flux for a period of 1-hour. In the first test, a near equilibrium temperature of 1862 K was attained in the center of the shield hot spot. In the second test, with increased incident flux, a near equilibrium temperature of 2072 K was achieved. The aperture shield sustained no visible damage as a result of the exposures. This paper describes the aperture shield thermal-vacuum qualification test program including the test article, test facility, procedures, data collection, test success criteria, results and conclusions.

  7. G-133: A soft x ray solar telescope

    NASA Technical Reports Server (NTRS)

    Williams, Memorie K.; Campbell, Branton; Roming, Peter W. A.; Spute, Mark K.; Moody, J. Ward

    1992-01-01

    The GOLDHELOX Project, NASA payload number G-133, is a robotic soft x ray solar telescope designed and built by an organization of undergraduate students. The telescope is designed to observe the sun at a wavelength of 171 to 181 A. Since we require observations free from atmospheric interference, the telescope will be launched in a NASA Get-Away-Special (GAS) canister with a Motorized Door Assembly (MDA). In this paper we primarily discuss the most important elements of the telescope itself. We also elaborate on some of the technical difficulties associated with doing good science in space on a small budget (about $100,000) and mention ways in which controlling the instrument environment has reduced the complexity of the system and thus saved us money.

  8. The science case and data processing strategy for the Thinned Aperture Light Collector (TALC): a project for a 20m far-infrared space telescope

    NASA Astrophysics Data System (ADS)

    Sauvage, Marc; Chanial, Pierre; Durand, Gilles A.; Rodriguez, Louis R.; Starck, Jean-Luc; Ronayette, Samuel; Aussel, Hervé; Minier, Vincent; Motte, Frédérique; Pantin, Eric J.; Sureau, Florent; Terrisse, Robin

    2014-08-01

    The future of far-infrared observations rests on our capacity to reach sub-arcsecond angular resolution around 100 ?m, in order to achieve a significant advance with respect to our current capabilities. Furthermore, by reaching this angular resolution we can bridge the gap between capacities offered by the JWST in the near infrared and those allowed by ALMA in the submillimeter, and thus benefit from similar resolving capacities over the whole wavelength range where interstellar dust radiates and where key atomic and molecular transitions are found. In an accompanying paper,1 we present a concept of a deployable annular telescope, named TALC for Thinned Aperture Light Collector, reaching 20m in diameter. Being annular, this telescope features a main beam width equivalent to that of a 27m telescope, i.e. an angular resolution of 0.92" at 100 ?m. In this paper we focus on the science case of such a telescope as well on the aspects of unconventional data processing that come with this unconventional optical configuration. The principal science cases of TALC revolve around its imaging capacities, that allow resolving the Kuiper belt in extra-solar planetary systems, or the filamentary scale in star forming clouds all the way to the Galactic Center, or the Narrow Line Region in Active Galactic Nuclei of the Local Group, or breaking the confusion limit to resolve the Cosmic Infrared Background. Equipping this telescope with detectors capable of imaging polarimetry offers as well the extremely interesting perspective to study the influence of the magnetic field in structuring the interstellar medium. We will then present simulations of the optical performance of such a telescope. The main feature of an annular telescope is the small amount of energy contained in the main beam, around 30% for the studied configuration, and the presence of bright diffraction rings. Using simulated point spread functions for realistic broad-band filters, we study the observing performance of TALC in typical situations, i.e a field of point sources, and fields with emission power at every physical scales, taken to represent an extragalactic deep field observation and an interstellar medium observation. We investigate different inversion techniques to try and recover the information present in the input field. We show that techniques combining a forward modeling of the observation process and a reconstruction algorithm exploiting the concept of sparsity (i.e. related to the more general field of compressed sensing) represent a promising avenue to reach the angular resolution promised by the main beam of TALC.

  9. Telescope beam-profile diagnostics and the solar limb

    SciTech Connect

    Lindsey, C.A.; Roellig, T.L. (Hawaii, University, Honolulu (USA) NASA, Ames Research Center, Moffett Field, CA (USA))

    1991-07-01

    The basic method is described for determining the solar limb brightness profile properly corrected for spurious limb darkening caused by the far wings of the resolving beams encountered in large far-infrared and radio telescopes. When the far wings of the beam can be independently measured this problem is usually amenable to standard deconvolution procedures. Under a broad range of well-defined cases, solutions to the deconvolution problem are unique to within the discrimination provided by the core of the beam profile. The theory is applied to solar limb scans made recently on the James Clerk Maxwell Telscope to show solar limb brightening in 850 micron radiation. 16 refs.

  10. Investigation of small solar system objects with the space telescope

    NASA Technical Reports Server (NTRS)

    Morrison, D.

    1979-01-01

    The application of the space telescope (ST) to study small objects in the solar system in order to understand the birth and the early evolution of the solar system is discussed. The upper size limit of the small bodies is defined as approximately 5000 km and includes planetary satellites, planetary rings, asteroids, and comets.The use of the astronomical instruments aboard the ST, such as the faint object camera, ultraviolet and infrared spectrometers, and spectrophotometers, to study the small solar system objects is discussed.

  11. Telescope beam-profile diagnostics and the solar limb

    NASA Technical Reports Server (NTRS)

    Lindsey, Charles A.; Roellig, Thomas L.

    1991-01-01

    The basic method is described for determining the solar limb brightness profile properly corrected for spurious limb darkening caused by the far wings of the resolving beams encountered in large far-infrared and radio telescopes. When the far wings of the beam can be independently measured this problem is usually amenable to standard deconvolution procedures. Under a broad range of well-defined cases, solutions to the deconvolution problem are unique to within the discrimination provided by the core of the beam profile. The theory is applied to solar limb scans made recently on the James Clerk Maxwell Telscope to show solar limb brightening in 850 micron radiation.

  12. PISCES: A Wide-Field, 1-2.5 mum Camera for Large-Aperture Telescopes

    Microsoft Academic Search

    D. W. McCarthy Jr.; J. Ge; J. L. Hinz; R. A. Finn; R. S. de Jong

    2001-01-01

    Wide-field-of-view infrared cameras, operating on the new generation of large telescopes, offer unprecedented gains in the detection of faint sources and in observing efficiency for both direct imaging and spectroscopy. With a 1024×1024 pixel, 1-2.5 mum detector, the PISCES camera provides 8.5' and 3.16' fields at the 2.3 m Bok telescope and 6.5 m Multiple Mirror Telescope, respectively. Its refractive

  13. Limiting sensitivities of coded-aperture telescopes for gamma-ray astronomy: Balloon-Borne fixed-mask systems

    NASA Astrophysics Data System (ADS)

    Owens, Alan

    1990-07-01

    The limiting sensitivities of coded-aperture imaging telescopes employing fixed masks are derived for continuum and line emission from cosmic point sources. The sensitivities are calculated for a single-source observation and do not take into consideration the many advantages offered by a multiplex system; for instance, low susceptibility to secular background changes and the ability to observe more than one source during an observation period. For the nuclear transition energy region, it is shown that the utilization of a coded-aperture mask by a particular detection system does not significantly degrade its performance relative to conventional, sequential scanning instruments. It is further shown that for short source observation times (e.g., typical of those obtained from stratospheric balloons), the coded-aperture imaging technique can be particularly advantageous. The effects of a non-uniform instrumental background on the imaging process are discussed and a correction procedure suggested. It is found that by careful planning of the observing program coupled with a stable instrument design, image degradation due to background non-uniformities can be made arbitrarily small and the resulting performance made to approach that predicted for an equivalent mask-antimask system. Present address: Laboratory for High Energy Astrophysics, Code 661, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.

  14. Solar tests of aperture plate materials for solar thermal dish collectors

    NASA Technical Reports Server (NTRS)

    Jaffe, L. D.

    1984-01-01

    If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fail apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

  15. Solar tests of aperture plate materials for solar thermal dish collectors

    NASA Technical Reports Server (NTRS)

    Jaffe, L. D.

    1984-01-01

    If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluoroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fall apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

  16. Solar Tests of Aperture Plate Materials for Solar Thermal Dish Collectors

    NASA Technical Reports Server (NTRS)

    Jaffe, L. D.

    1984-01-01

    If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the Sun, motion of the concentrator may stop. As the Sun moves relative to the Earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluoroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fall apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

  17. Search for Solar Axions with the CCD Detector and X-ray Telescope at CAST Experiment

    E-print Network

    Rosu, Madalin Mihai; Zioutas, Konstantin

    2015-06-09

    The CERN Axion Solar Telescope (CAST) is an experiment that uses the world’s highest sensitivity Helioscope to date for solar Axions searches. Axions are weakly interacting pseudoscalar particles proposed to solve the so-called Strong Charge-Parity Problem of the Standard Model. The principle of detection is the inverse Primakoff Effect, which is a mechanism for converting the Axions into easily detectable X-ray photons in a strong transverse magnetic field. The solar Axions are produced due to the Primakoff effect in the hot and dense core of from the coupling of a real and a virtual photon. The solar models predict a peak Axion luminosity at an energy of 3 keV originating mostly from the inner 20% of the solar radius. Thus an intensity peak at an energy of 3 keV is also expected in the case of the X-ray radiation resulting from Axion conversion. CAST uses a high precision movement system for tracking the Sun twice a day with a LHC dipole twin aperture prototype magnet, 9.26 meters long and with a field of...

  18. Spectrograph capabilities of the European Solar Telescope

    NASA Astrophysics Data System (ADS)

    Calcines, A.; Collados, M.; Feller, A.; Grauf, B.; Grivel-Gelly, C.; Hirzberger, J.; López Ariste, A.; López López, R.; Mein, P.; Sayčde, F.

    2010-07-01

    EST is a project for a 4-meter class telescope to be located in the Canary Islands. EST will be optimized for studies of the magnetic coupling between the photosphere and the chromosphere. This requires high spatial and temporal resolution diagnostics tools of properties of the plasma, by using multiple wavelength spectropolarimetry. To achieve these goals, visible and near-IR multi-purpose spectrographs are being designed to be compatible with different modes of use: LsSS (Long-slit Standard Spectrograph), multi-slit multi-wavelength spectrograph with an integral field unit, TUNIS (Tunable Universal Narrow-band Imaging Spectrograph), and new generation MSDP (Multi-channel Subtractive Double-pass Spectrograph). In this contribution, these different instrumental configurations are described.

  19. First Results from the CERN Axion Solar Telescope

    Microsoft Academic Search

    K. Zioutas; S. Andriamonje; V. Arsov; S. Aune; D. Autiero; F. T. Avignone; K. Barth; A. Belov; B. Beltrán; H. Bräuninger; J. M. Carmona; S. Cebrián; E. Chesi; J. I. Collar; R. Creswick; T. Dafni; M. Davenport; L. di Lella; C. Eleftheriadis; J. Englhauser; G. Fanourakis; H. Farach; E. Ferrer; H. Fischer; J. Franz; P. Friedrich; T. Geralis; I. Giomataris; S. Gninenko; N. Goloubev; M. D. Hasinoff; F. H. Heinsius; D. H. Hoffmann; I. G. Irastorza; J. Jacoby; D. Kang; K. Königsmann; R. Kotthaus; M. Krcmar; K. Kousouris; M. Kuster; B. Lakic; C. Lasseur; A. Liolios; A. Ljubicic; G. Lutz; G. Luzón; D. W. Miller; A. Morales; J. Morales; M. Mutterer; A. Nikolaidis; A. Ortiz; T. Papaevangelou; A. Placci; G. Raffelt; J. Ruz; H. Riege; M. L. Sarsa; I. Savvidis; W. Serber; P. Serpico; Y. Semertzidis; L. Stewart; J. D. Vieira; J. Villar; L. Walckiers; K. Zachariadou

    2005-01-01

    Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field (``axion helioscope''), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from

  20. The Advanced Technology Large Aperture Space Telescope (ATLAST): Science Drivers, Technology Developments, and Synergies with Other Future Facilities

    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 that define the main performance requirements for ATLAST (8 to 16 milliarcsec 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 will also discuss the synergy between ATLAST and other anticipated future facilities (e.g., TMT, EELT, ALMA) and the priorities for technology development that will enable the construction for a cost that is comparable to current generation observatory-class space missions.

  1. On the co-alignment of solar telescopes. A new approach to solar pointing

    NASA Astrophysics Data System (ADS)

    Staiger, J.

    2013-06-01

    Helioseismological measurements require long observing times and thus may be adversely affected by lateral image drifts as caused by pointing instabilities. At the Vacuum Tower Telescope VTT, Tenerife we have recorded drift values of up to 5" per hour under unstable thermal conditions (dome opening, strong day-to-day thermal gradients). Typically drifts of 0.5" - 1.0" per hour may be encountered under more favorable conditions. Past experience has shown that most high-resolution solar telescopes may be affected by this problem to some degree. This inherent shortcoming of solar pointing is caused by the fact that the guiding loop can be closed only within the guiding beam but not within the telescope's main beam. We have developed a new approach to this problem. We correlate continuum brightness patterns observed from within the telescope main beam with patterns originating from a full disk telescope. We show that brightness patterns of sufficient size are unique with respect to solar location at any instant of time and may serve as a location identifier. We make use of the fact that averaged location information of solar structures is invariant with respect to telescope resolution. We have carried out tests at the VTT together with SDO. We have used SDO as a full disk reference. We were able to reduce lateral image drifts by an order of magnitude.

  2. High-resolution Imaging of the Upper Solar Chromosphere: First Light Performance of the Very-high-Resolution Advanced ULtraviolet Telescope

    NASA Astrophysics Data System (ADS)

    Korendyke, C. M.; Vourlidas, A.; Cook, J. W.; Dere, K. P.; Howard, R. A.; Morrill, J. S.; Moses, J. D.; Moulton, N. E.; Socker, D. G.

    2001-05-01

    The Very-high-resolution Advanced ULtraviolet Telescope (VAULT) experiment was successfully launched on 7 May 1999 on a Black Brant sounding rocket vehicle from White Sands Missile Range. The instrument consists of a 30 cm UV diffraction limited telescope followed by a two-grating, zero-dispersion spectroheliograph tuned to isolate the solar L? emission line. During the flight, the instrument successfully obtained a series of images of the upper chromosphere with a limiting resolution of ~0.33 arc sec. The resulting observations are the highest-resolution images of the solar atmosphere obtained from space to date. The flight demonstrated that sub-arc second ultraviolet images of the solar atmosphere are achievable with a high-quality, moderate-aperture space telescope and associated optics. Herein, we describe the payload and its in-flight performance.

  3. Extra Solar Planetary Imaging Coronagraph and Science Requirements for the James Webb Telescope Observatory

    NASA Technical Reports Server (NTRS)

    Clampin, Mark

    2004-01-01

    1) Extra solar planetary imaging coronagraph. Direct detection and characterization of Jovian planets, and other gas giants, in orbit around nearby stars is a necessary precursor to Terrestrial Planet Finder 0 in order to estimate the probability of Terrestrial planets in our stellar neighborhood. Ground based indirect methods are biased towards large close in Jovian planets in solar systems unlikely io harbor Earthlike planets. Thus to estimate the relative abundances of terrestrial planets and to determine optimal observing strategies for TPF a pathfinder mission would be desired. The Extra-Solar Planetary Imaging Coronagraph (EPIC) is such a pathfinder mission. Upto 83 stellar systems are accessible with a 1.5 meter unobscured telescope and coronagraph combination located at the Earth-Sun L2 point. Incorporating radiometric and angular resolution considerations show that Jovians could be directly detected (5 sigma) in the 0.5 - 1.0 micron band outside of an inner working distance of 5/D with integration times of -10 - 100 hours per observation. The primary considerations for a planet imager are optical wavefront quality due to manufacturing, alignment, structural and thermal considerations. pointing stability and control, and manufacturability of coronagraphic masks and stops to increase the planetary-to- stellar contrast and mitigate against straylight. Previously proposed coronagraphic concepts are driven to extreme tolerances. however. we have developed and studied a mission, telescope and coronagraphic detection concept, which is achievable in the time frame of a Discovery class NASA mission. 2) Science requirements for the James Webb Space Telescope observatory. The James Webb Space Observatory (JWST) is an infrared observatory, which will be launched in 201 1 to an orbit at L2. JWST is a segmented, 18 mirror segment telescope with a diameter of 6.5 meters, and a clear aperture of 25 mA2. The telescope is designed to conduct imaging and spectroscopic observations from 0.6-27 microns. The primary mirror find and understand predicted first light objects, observe galaxies back to their earliest precursors so that we can understand their growth and evolution, unravel the birth and early evolution of stars and planetary systems, and study planetary systems and the origins of life. In this paper we discuss the science goals for JWST in the context of the performance requirements they levy on the observatory.

  4. Observing Solar System Targets with the James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Norwood, James; Hammel, Heidi; Milam, Stefanie; Stansberry, John; Lunine, Jonathan; Chanover, Nancy; Hines, Dean; Sonneborn, George; Tiscareno, Matthew; Brown, Michael; Ferruit, Pierre

    2014-11-01

    With its anticipated launch date in October 2018, the James Webb Space Telescope will tremendously advance astronomy in the near- and mid-infrared, offering sensitivity and spatial/spectral resolution greatly surpassing its predecessors. We have developed a white paper that explores observations of Solar System targets with JWST, with the goals of highlighting anticipated Solar System capabilities, motivation of potential observers, and encouragement of further interest and discussion. This paper presents the most current information available concerning JWST instrument properties and observing techniques relevant to planetary science. It also illustrates example observing scenarios for a wide variety of Solar System objects, including the giant planets, Kuiper Belt objects, Europa, Titan, and more. We are also collaborating with a set of focus groups that have expanded upon this work, producing a series of further white papers dealing with individual subdisciplines. This work has been supported by NASA Grant NAG5-12457.

  5. Hubble Space Telescope solar cell module thermal cycle test

    NASA Technical Reports Server (NTRS)

    Douglas, Alexander; Edge, Ted; Willowby, Douglas; Gerlach, Lothar

    1992-01-01

    The Hubble Space Telescope (HST) solar array consists of two identical double roll-out wings designed after the Hughes flexible roll-up solar array (FRUSA) and was developed by the European Space Agency (ESA) to meet specified HST power output requirements at the end of 2 years, with a functional lifetime of 5 years. The requirement that the HST solar array remain functional both mechanically and electrically during its 5-year lifetime meant that the array must withstand 30,000 low Earth orbit (LEO) thermal cycles between approximately +100 and -100 C. In order to evaluate the ability of the array to meet this requirement, an accelerated thermal cycle test in vacuum was conducted at NASA's Marshall Space Flight Center (MSFC), using two 128-cell solar array modules which duplicated the flight HST solar array. Several other tests were performed on the modules. The thermal cycle test was interrupted after 2,577 cycles, and a 'cold-roll' test was performed on one of the modules in order to evaluate the ability of the flight array to survive an emergency deployment during the dark (cold) portion of an orbit. A posttest static shadow test was performed on one of the modules in order to analyze temperature gradients across the module. Finally, current in-flight electrical performance data from the actual HST flight solar array will be tested.

  6. Site-seeing measurements for the European Solar Telescope

    NASA Astrophysics Data System (ADS)

    Berkefeld, Th.; Bettonvil, F.; Collados, M.; López, R.; Martín, Y.; Peńate, J.; Pérez, A.; Scharmer, G. B.; Sliepen, G.; Soltau, D.; Waldmann, T. A.; van Werkhoven, T.

    2010-07-01

    Seeing measurements are crucial for the optimum design of (multi-conjugate) adaptive optics systems operating at solar telescopes. For the design study of the 4-meter European Solar Telescope, to be located in the Canary Islands, several instruments have been constructed and operated, at the Observatorio del Roque de los Muchachos (La Palma) and at the Observatorio del Teide (Tenerife), to measure the properties of the ground layer and medium-high altitude turbulence. Several units of short (42.34 cm) and two long (323.06 cm) scintillometer bars are, or are to be, installed at both observatories. In addition to them, two wide-field wavefront sensors will be attached to the optical beams of the Swedish tower, on La Palma, and of the German VTT, on Tenerife, simultaneously used with the normal operation of the telescopes. These wavefront sensors are of Shack-Hartmann type with ~1 arcminute field of view. In this contribution, the instruments setup and their performance are described.

  7. High-contrast imager for Complex Aperture Telescopes (HiCAT): APLC/shaped-pupil hybrid coronagraph designs

    NASA Astrophysics Data System (ADS)

    N'Diaye, Mamadou; Choquet, Elodie; Carlotti, Alexis; Pueyo, Laurent; Egron, Sylvain; Leboulleux, Lucie; Levecq, Olivier; Perrin, Marshall D.; Wallace, J. Kent; Long, Chris; Lajoie, Rachel; Lajoie, Charles-Philippe; Eldorado Riggs, A. J.; Zimmerman, Neil T.; Groff, Tyler Dean; Kasdin, N. Jeremy; Vanderbei, Robert J.; Mawet, Dimitri; Macintosh, Bruce; Shaklan, Stuart; Soummer, Remi

    2015-01-01

    HiCAT is a high-contrast imaging testbed designed to provide complete solutions in wavefront sensing, control and starlight suppression with complex aperture telescopes. Primary mirror segmentation, central obstruction and spiders in the pupil of an on-axis telescope introduces additional diffraction features in the point spread function, which make high-contrast imaging very challenging. The testbed alignment was completed in the summer of 2014, exceeding specifications with a total wavefront error of 12nm rms with a 18mm pupil. Two deformable mirrors are to be installed for wavefront control in the fall of 2014. In this communication, we report on the first testbed results using a classical Lyot coronagraph. We have developed novel coronagraph designs combining an Apodized Pupil Lyot Coronagraph (APLC) with shaped-pupil type optimizations. We present the results of these new APLC-type solutions with two-dimensional shaped-pupil apodizers for the HiCAT geometry. These solutions render the system quasi-insensitive to jitter and low-order aberrations, while improving the performance in terms of inner working angle, bandpass and contrast over a classical APLC.

  8. Fibered nulling telescope for extra-solar coronagraphy.

    PubMed

    Hénault, François

    2009-04-01

    A family of fibered nulling telescopes is described, based on the joint use of several recent suggested or demonstrated techniques, namely, pupil densification, multiaxial recombination and single-mode fiber modal filtering, and the use of a fully symmetric beam splitter arrangement. The concept seems appropriate for the realization of a spaceborne nulling telescope, searching for Jupiter-like extra-solar planets and a precursor of future missions, such as Darwin or terrestrial planet finder interferometer (TPF-I). However, it is generally not possible to satisfy at the same time two major requirements, being the depth and size of the central nulling area, and the global throughput for the observed planet. PMID:19340231

  9. Detection of Small-scale Granular Structures in the Quiet Sun with the New Solar Telescope

    NASA Astrophysics Data System (ADS)

    Abramenko, V. I.; Yurchyshyn, V. B.; Goode, P. R.; Kitiashvili, I. N.; Kosovichev, A. G.

    2012-09-01

    Results of a statistical analysis of solar granulation are presented. A data set of 36 images of a quiet-Sun area on the solar disk center was used. The data were obtained with the 1.6 m clear aperture New Solar Telescope at Big Bear Solar Observatory and with a broadband filter centered at the TiO (705.7 nm) spectral line. The very high spatial resolution of the data (diffraction limit of 77 km and pixel scale of 0farcs0375) augmented by the very high image contrast (15.5% ± 0.6%) allowed us to detect for the first time a distinct subpopulation of mini-granular structures. These structures are dominant on spatial scales below 600 km. Their size is distributed as a power law with an index of -1.8 (which is close to the Kolmogorov's -5/3 law) and no predominant scale. The regular granules display a Gaussian (normal) size distribution with a mean diameter of 1050 km. Mini-granular structures contribute significantly to the total granular area. They are predominantly confined to the wide dark lanes between regular granules and often form chains and clusters, but different from magnetic bright points. A multi-fractality test reveals that the structures smaller than 600 km represent a multi-fractal, whereas on larger scales the granulation pattern shows no multi-fractality and can be considered as a Gaussian random field. The origin, properties, and role of the population of mini-granular structures in the solar magnetoconvection are yet to be explored.

  10. DETECTION OF SMALL-SCALE GRANULAR STRUCTURES IN THE QUIET SUN WITH THE NEW SOLAR TELESCOPE

    SciTech Connect

    Abramenko, V. I.; Yurchyshyn, V. B.; Goode, P. R. [Big Bear Solar Observatory, 40386 N. Shore Lane, Big Bear City, CA 92314 (United States); Kitiashvili, I. N.; Kosovichev, A. G. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2012-09-10

    Results of a statistical analysis of solar granulation are presented. A data set of 36 images of a quiet-Sun area on the solar disk center was used. The data were obtained with the 1.6 m clear aperture New Solar Telescope at Big Bear Solar Observatory and with a broadband filter centered at the TiO (705.7 nm) spectral line. The very high spatial resolution of the data (diffraction limit of 77 km and pixel scale of 0.''0375) augmented by the very high image contrast (15.5% {+-} 0.6%) allowed us to detect for the first time a distinct subpopulation of mini-granular structures. These structures are dominant on spatial scales below 600 km. Their size is distributed as a power law with an index of -1.8 (which is close to the Kolmogorov's -5/3 law) and no predominant scale. The regular granules display a Gaussian (normal) size distribution with a mean diameter of 1050 km. Mini-granular structures contribute significantly to the total granular area. They are predominantly confined to the wide dark lanes between regular granules and often form chains and clusters, but different from magnetic bright points. A multi-fractality test reveals that the structures smaller than 600 km represent a multi-fractal, whereas on larger scales the granulation pattern shows no multi-fractality and can be considered as a Gaussian random field. The origin, properties, and role of the population of mini-granular structures in the solar magnetoconvection are yet to be explored.

  11. Engineering Specification for Large-aperture UVO Space Telescopes Derived from Science Requirements

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Postman, Mark; Smith, W. Scott

    2013-01-01

    The Advance Mirror Technology Development (AMTD) project is a three year effort initiated in FY12 to mature by at least a half TRL step six critical technologies required to enable 4 to 8 meter UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. To provide the science community with options, we are pursuing multiple technology paths. We have assembled an outstanding team from academia, industry, and government with extensive expertise in astrophysics and exoplanet characterization, and in the design/manufacture of monolithic and segmented space telescopes. A key accomplishment is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints.

  12. POlarization Emission of Millimeter Activity at the Sun (POEMAS): New Circular Polarization Solar Telescopes at Two Millimeter Wavelength Ranges

    NASA Astrophysics Data System (ADS)

    Valio, Adriana; Kaufmann, P.; Giménez de Castro, C. G.; Raulin, J.-P.; Fernandes, L. O. T.; Marun, A.

    2013-04-01

    We present a new system of two circular polarization solar radio telescopes, POEMAS, for observations of the Sun at 45 and 90 GHz. The novel characteristic of these instruments is the capability to measure circular right- and left-hand polarizations at these high frequencies. The two frequencies were chosen so as to bridge the gap at radio frequencies between 20 and 200 GHz of solar flare spectra. The telescopes, installed at CASLEO Observatory (Argentina), observe the full disk of the Sun with a half power beam width of 1.4?, a time resolution of 10 ms at both frequencies, a sensitivity of 2 - 4 K that corresponds to 4 and 20 solar flux unit (=104 Jy), considering aperture efficiencies of 50±5 % and 75±8 % at 45 and 90 GHz, respectively. The telescope system saw first light in November 2011 and is satisfactorily operating daily since then. A few flares were observed and are presented here. The millimeter spectra of some flares are seen to rise toward higher frequencies, indicating the presence of a new spectral component distinct from the microwave one.

  13. Adjustment of a tower solar telescope and spectrograph: A method manual

    NASA Astrophysics Data System (ADS)

    Stepanian, N. N.; Sunitsa, G. A.; Malashchuk, V. M.

    2014-06-01

    Questions of the mounting and adjustment of a tower solar telescope are considered through the example of the TST-2 telescope of the Crimean Astrophysical Observatory Scientific Research Institute. The authors describe the optical circuits of the telescope and spectrograph and list the basic requirements for the mutual arrangement of individual components of the telescope. Simple methods for adjusting elements of the telescope and spectrograph are described.

  14. Development of multilayer coatings for solar orbiter EUV imaging telescopes

    NASA Astrophysics Data System (ADS)

    Delmotte, Franck; Meltchakov, Evgueni; de Rossi, Sébastien; Bridou, Françoise; Jérome, Arnaud; Varničre, François; Mercier, Raymond; Auchčre, Frédéric; Zhang, Xueyan; Borgo, Bruno; Dumesnil, Cydalise; François, Serge; Roulliay, Marc; Strauch, Udo

    2013-09-01

    Since more than 20 years, Laboratoire Charles Fabry and Institut d'Astrophysique Spatiale are involved in development of the EUV multilayer coating for solar imaging. Previous instruments, such as the SOHO EIT and STEREO EUVI telescopes, employed the Mo/Si multilayer coatings, which offered at that time the best efficiency and stability. We present here recent results of the development of highly efficient EUV multilayers coatings at 17.4 nm and 30.4 nm for the Solar Orbiter mission. New multilayer structures, based on a combination of three materials including aluminum, have been optimized both theoretically and experimentally. We have succeeded to reduce interfacial roughness of Albased multilayers down to 0.5 nm via optimization of the multilayer design and the deposition process. The EUV peak reflectance of Al/Mo/SiC and Al/Mo/B4C multilayer coatings reaches 56% at 17.4 nm, the highest value reported up to now for this wavelength. We have also optimized specific bi-periodic structures that possess two reflection bands in the EUV range with high spectral selectivity. The EUV reflectivity of these Al-based dual-band coatings are compared with the Si/Mo/B4C baseline coating for Solar Orbiter. Since the stability of reflecting multilayer coating is an important issue for space missions, we have also studied the temporal stability as well as the resistivity of the coatings to thermal cycling and to proton irradiation. Experimental results confirm that Al/Mo/SiC and Al/Mo/B4C multilayer coatings are good candidates for the Solar Orbiter EUV imaging telescopes.

  15. High Resolution Observations of Solar Quiescent Prominences with the Hinode Solar Optical Telescope: an Open Challenge to 21st Century Ground-based Solar Telescopes (Invited)

    NASA Astrophysics Data System (ADS)

    Berger, T. E.

    2009-12-01

    The Solar Optical Telescope (SOT) on the Japanese Hinode satellite is a 0.5-meter diameter Gregorian solar telescope in a 600 km Sun-synchronous orbit. The telescope achieves diffraction-limited imaging with no atmospheric seeing in a wavelength range from 380 nm to 660 nm. Using both the Broadband Filter Imager (BFI) Ca II H-line channel at 389.6 nm and the tunable Narrowband Filter Imager (NFI) H-alpha channel at 656.3 nm we have observed many quiescent solar prominences since the satellite launch in September 2006. The excellent optical quality and low scattering of the SOT telescope combined with the lack of atmospheric scattering and seeing enables us to capture multi-hour diffraction-limited movies of quiescent prominences above the limb that achieve 200 km spatial resolution and 15--30 second temporal resolution. These SOT observations have led to the discovery of new flows in the solar outer atmosphere in the form of buoyant small-scale (2--6 Mm) plumes and large-scale (10--50 Mm) "bubbles" or arches that originate below quiescent prominences and rise with speeds of 10--30 km/sec to heights of 10--30+ Mm above the solar limb. In this talk we review the kinematic properties of these new flows in combination with the long-observed filamentary downflows to show that quisecent prominences are not magnetostatic structures "suspended against gravity" but are rather entirely dynamic structures in which mass is continually drained in the downflows while being resupplied largely by condensation from the coronal cavity above and episodic buoyant flows from below. The Hinode/SOT instrument has definitively shown the value of flying high-resolution visible-light solar telescopes in space by acheiving in its first six months what had been a long-standing goal of ground-based solar prominence research for the past 50 years. However many key quiescent prominence characteristics cannot be measured by the limited instrumentation on the Hinode satellite. Primary among these is vector magnetic field in prominences at high spatial and temporal resolution and the thermodynamic and magnetic characteristics of the new plume and bubble flows. It is hoped that the new generation of adaptive-optics ground-based telescopes such as the 1.6-m NST can make progress in these areas while we await the next solar space telescope missions.

  16. Solar multiconjugate adaptive optics at the Dunn Solar Telescope: preliminary results

    Microsoft Academic Search

    Maud Langlois; Gil Moretto; Kit Richards; Steve Hegwer; Thomas R. Rimmele

    2004-01-01

    We report here the preliminary results obtained with the multi-conjugate adaptive optics (MCAO) system at the Dunn Solar Telescope (DST\\/NSO MCAO) and the optical setup and performances are presented in more details in Moretto et al. in this proceeding. This system relies on the tomography technique, in which three WFS are used, each of them coupled to extended images of

  17. 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.

  18. Solar System Observing with the Space Infrared Telescope Facility (SIRTF)

    NASA Technical Reports Server (NTRS)

    Cleve, J. Van; Meadows, V. S.; Stansberry, J.

    2003-01-01

    SIRTF is NASA's Space Infrared Telescope Facility. Currently planned for launch on 15 Apr 2003, it is the final element in NASA's Great Observatories Program. SIRTF has an 85 cm diameter f/12 lightweight beryllium telescope, cooled to lekss than 5.5K. It is diffraction-limited at 6.5 microns, and has wavelengthcoverage from 3-180 microns. Its estimated lifetime (limited by cryogen) is 2.5 years at minimum, with a goal of 5+ years. SIRTF has three instruments, IRAC, IRS, and MIPS. IRAC (InfraRed Array Camera) provides simultaneous images at wavelengths of 3.6, 4.5, 5.8, and 8.0 microns. IRS (InfraRed Spectrograph) has 4 modules providing low-resolution (R=60-120) spectra from 5.3 to 40 microns, high-resolution (R=600) spectra from 10 to 37 microns, and an autonomous target acquisition system (PeakUp) which includes small-field imaging at 15 microns. MIPS (Multiband Imaging Photometer for SIRTF)} does imaging photometry at 24, 70, and 160 m and low-resolution (R=15-25) spectroscopy (SED) between 55 and 96 microns. The SIRTF Guaranteed Time Observers (GTOs) are planning to observe Outer Solar System satellites and planets, extinct comets and low-albedo asteroids, Centaurs and Kuiper Belt Objects, cometary dust trails, and a few active short-period comets. The GTO programs are listed in detail in the SIRTF Reserved Observations Catalog (ROC). We would like to emphasize that there remain many interesting subjects for the General Observers (GO). Proposal success for the planetary observer community in the first SIRTF GO proposal cycle (GO-1) determines expectations for future GO calls and Solar System use of SIRTF, so we would like promote a strong set of planetary GO-1 proposals. Towards that end, we present this poster, and we will convene a Solar System GO workshop 3.5 months after launch.

  19. Lupus I Observations from the 2010 Flight of the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry

    NASA Astrophysics Data System (ADS)

    Matthews, Tristan G.; Ade, Peter A. R.; Angilč, Francesco E.; Benton, Steven J.; Chapin, Edward L.; Chapman, Nicholas L.; Devlin, Mark J.; Fissel, Laura M.; Fukui, Yasuo; Gandilo, Natalie N.; Gundersen, Joshua O.; Hargrave, Peter C.; Klein, Jeffrey; Korotkov, Andrei L.; Moncelsi, Lorenzo; Mroczkowski, Tony K.; Netterfield, Calvin B.; Novak, Giles; Nutter, David; Olmi, Luca; Pascale, Enzo; Poidevin, Frédérick; Savini, Giorgio; Scott, Douglas; Shariff, Jamil A.; Soler, Juan Diego; Tachihara, Kengo; Thomas, Nicholas E.; Truch, Matthew D. P.; Tucker, Carole E.; Tucker, Gregory S.; Ward-Thompson, Derek

    2014-04-01

    The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was created by adding polarimetric capability to the BLAST experiment that was flown in 2003, 2005, and 2006. BLASTPol inherited BLAST's 1.8 m primary and its Herschel/SPIRE heritage focal plane that allows simultaneous observation at 250, 350, and 500 ?m. We flew BLASTPol in 2010 and again in 2012. Both were long duration Antarctic flights. Here we present polarimetry of the nearby filamentary dark cloud Lupus I obtained during the 2010 flight. Despite limitations imposed by the effects of a damaged optical component, we were able to clearly detect submillimeter polarization on degree scales. We compare the resulting BLASTPol magnetic field map with a similar map made via optical polarimetry. (The optical data were published in 1998 by J. Rizzo and collaborators.) The two maps partially overlap and are reasonably consistent with one another. We compare these magnetic field maps to the orientations of filaments in Lupus I, and we find that the dominant filament in the cloud is approximately perpendicular to the large-scale field, while secondary filaments appear to run parallel to the magnetic fields in their vicinities. This is similar to what is observed in Serpens South via near-IR polarimetry, and consistent with what is seen in MHD simulations by F. Nakamura and Z. Li.

  20. Lupus I Observations from the 2010 Flight of the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry

    E-print Network

    Matthews, Tristan G; Angilč, Francesco E; Benton, Steven J; Chapin, Edward L; Chapman, Nicholas L; Devlin, Mark J; Fissel, Laura M; Fukui, Yasuo; Gandilo, Natalie N; Gundersen, Joshua O; Hargrave, Peter C; Klein, Jeffrey; Korotkov, Andrei L; Moncelsi, Lorenzo; Mroczkowski, Tony K; Netterfield, Calvin B; Novak, Giles; Nutter, David; Olmi, Luca; Pascale, Enzo; Poidevin, Frédérick; Savini, Giorgio; Scott, Douglas; Shariff, Jamil A; Soler, Juan Diego; Tachihara, Kengo; Thomas, Nicholas E; Truch, Matthew D P; Tucker, Carole E; Tucker, Gregory S; Ward-Thompson, Derek

    2013-01-01

    The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was created by adding polarimetric capability to the BLAST experiment that was flown in 2003, 2005, and 2006. BLASTPol inherited BLAST's 1.8 m primary and its Herschel/SPIRE heritage focal plane that allows simultaneous observation at 250, 350, and 500 {\\mu}m. We flew BLASTPol in 2010 and again in 2012. Both were long duration Antarctic flights. Here we present polarimetry of the nearby filamentary dark cloud Lupus I obtained during the 2010 flight. Despite limitations imposed by the effects of a damaged optical component, we were able to clearly detect submillimeter polarization on degree scales. We compare the resulting BLASTPol magnetic field map with a similar map made via optical polarimetry (The optical data were published in 1998 by J. Rizzo and collaborators.). The two maps partially overlap and are reasonably consistent with one another. We compare these magnetic field maps to the orientations of filaments in Lupus I,...

  1. Searching for extra-solar planets using the PIRATE telescope Third Year Project: May 2009

    E-print Network

    Kolb, Ulrich

    Searching for extra-solar planets using the PIRATE telescope Third Year Project: May 2009 Samantha Supervisor: Dr. M. Burleigh Abstract PIRATE (Physics Innovations Robotic Astronomical Telescope Explorer to discover that it was possible to do this kind of science with the PIRATE telescope. A light curve

  2. Hubble Space Telescope solar array change-out, mission anomalies and returned flight hardware

    Microsoft Academic Search

    Cindy Winslow

    1995-01-01

    During the successful First Servicing Mission on the Hubble Space Telescope the two solar arrays were replaced with new and improved solar arrays. An electrical short and four solar array mechanical system anomalies occurred: (1) the upper outer bistem on the +V2 wing had developed kinks and then failed to retract; (2) additional friction between the solar array latch fitting

  3. The Solar Optical Telescope for the Hinode Mission: An Overview

    Microsoft Academic Search

    S. Tsuneta; K. Ichimoto; Y. Katsukawa; S. Nagata; M. Otsubo; T. Shimizu; Y. Suematsu; M. Nakagiri; M. Noguchi; T. Tarbell; R. Shine; W. Rosenberg; C. Hoffmann; B. Jurcevich; G. Kushner; M. Levay; B. Lites; D. Elmore; T. Matsushita; N. Kawaguchi; H. Saito; I. Mikami; L. D. Hill; J. K. Owens

    2008-01-01

    The Solar Optical Telescope (SOT) aboard the Hinode satellite (formerly called Solar-B) consists of the Optical Telescope Assembly (OTA) and the Focal Plane Package (FPP). The OTA is a 50-cm diffraction-limited\\u000a Gregorian telescope, and the FPP includes the narrowband filtergraph (NFI) and the broadband filtergraph (BFI), plus the Stokes\\u000a Spectro-Polarimeter (SP). The SOT provides unprecedented high-resolution photometric and vector magnetic

  4. First results from the CERN axion solar telescope.

    PubMed

    Zioutas, K; Andriamonje, S; Arsov, V; Aune, S; Autiero, D; Avignone, F T; Barth, K; Belov, A; Beltrán, B; Bräuninger, H; Carmona, J M; Cebrián, S; Chesi, E; Collar, J I; Creswick, R; Dafni, T; Davenport, M; Di Lella, L; Eleftheriadis, C; Englhauser, J; Fanourakis, G; Farach, H; Ferrer, E; Fischer, H; Franz, J; Friedrich, P; Geralis, T; Giomataris, I; Gninenko, S; Goloubev, N; Hasinoff, M D; Heinsius, F H; Hoffmann, D H H; Irastorza, I G; Jacoby, J; Kang, D; Königsmann, K; Kotthaus, R; Krcmar, M; Kousouris, K; Kuster, M; Laki?, B; Lasseur, C; Liolios, A; Ljubici?, A; Lutz, G; Luzón, G; Miller, D W; Morales, A; Morales, J; Mutterer, M; Nikolaidis, A; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, G; Ruz, J; Riege, H; Sarsa, M L; Savvidis, I; Serber, W; Serpico, P; Semertzidis, Y; Stewart, L; Vieira, J D; Villar, J; Walckiers, L; Zachariadou, K

    2005-04-01

    Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses. PMID:15903903

  5. Solar System Studies with the Space Infrared Telescope Facility (SIRTF)

    NASA Technical Reports Server (NTRS)

    Cruikshank, Dale P.; DeVincenzi, Donald L. (Technical Monitor)

    1998-01-01

    SIRTF (Space Infrared Telescope Facility) is the final element in NASA's 'Great Observatories' program. It consists of an 85-cm cryogenically-cooled observatory for infrared astronomy from space. SIRTF is scheduled for launch in late 2001 or early 2002 on a Delta rocket into a heliocentric orbit trailing the Earth. Data from SIRTF will be processed and disseminated to the community through the SIRTF Science Center (SSC) located at the Infrared Processing and Analysis Center (IPAC) at Caltech. Some 80/% of the total observing time (estimated at a minimum of 7500 hours of integration time per year for the mission lifetime of about 4 years) will be available to the scientific community at large through a system of refereed proposals. Three basic instruments are located in the SIRTF focal plane. The Multiband Imaging Photometer (MIPS), the Infrared Array Camera (IRAC), and the Infrared Spectrometer (IRS), taken together, provide imaging and spectroscopy from 3.5 to 160 microns. Among the solar system studies suited to SIRTF are the following: 1) spectroscopy and radiometry of small bodies from the asteroid main belt, through the Trojan clouds, to the Kuiper Disk; 2) dust distribution in the zodiacal cloud and the Earth's heliocentric dust ring; 3) spectroscopy and radiometry of comets; and 4) spectroscopy and radiometry of planets and their satellites. Searches for, and studies of dust disks around other stars, brown dwarfs, and superplanets will also be conducted with SIRTF. The SORTIE web site (http://ssc.ipac.caltech.edu/sirtf) contains important details and documentation on the project, the spacecraft, the telescope, instruments, and observing procedures. A community-wide workshop for solar system studies with SIRTF is in the planning stages by the author and Martha S. Hanner for the summer of 1999.

  6. Next-generation Solar Data and Data Services from the Daniel K. Inouye Solar Telescope

    NASA Astrophysics Data System (ADS)

    Berukoff, S. J.; Reardon, K.; Rimmele, T.

    2014-12-01

    The Daniel K. Inouye Solar Telescope (DKIST), when completed in 2019, will be the largest, most capable, solar telescope in the world. Currently under construction on the summit of Haleakal? on Maui, the DKIST will enable foundational insights into the physics of the Sun's photosphere, chromosphere, and corona. Its suite of first-light instruments will produce approximately 25 TB of raw data per day, with occasional bursts of 50TB per day. These high data rates will require a scalable, flexible data and computing architecture that enables and promotes scientific inquiry and discovery. We briefly describe the DKIST data stream and then provide an overview of the proposed data-center architecture and resources that will allow users to fully exploit this world-class facility.

  7. Future Diagnostic Capabilities: The 4-meter Daniel K. Inouye Solar Telescope

    NASA Astrophysics Data System (ADS)

    Berger, Thomas; Reardon, Kevin; Elmore, David; Woeger, Friedrich; Tritschler, Alexandra; Rimmele, Thomas

    We discuss the observational capabilities of the Daniel K. Inouye Solar Telescope (DKSIT), formerly known as the Advanced Technology Solar Telescope (ATST), currently under construction on Haleakala Mountain on the island of Maui, Hawaii, with first light anticipated in mid-2019. The DKIST will be a 4-meter aperture Gregorian telescope with advanced environmental control and adaptive optics capable of producing diffraction-limited resolution in visible light of 0.03" or about 20 km in the solar photosphere. The first light instrument suite will include the Visible Broadband Imager (VBI), an interference filter-based instrument capable of 30 Hz imaging of photospheric and chromospheric magnetic structures in the 380 to 800 nm wavelength range. All VBI images will be reconstructed in near-real-time using the KISIP speckle reconstruction algorithm adapted to the DKIST optical and AO configuration. The Visible Spectropolarimeter (ViSP) instrument being fabricated by the High Altitude Observatory (HAO) will enable high-precision slit-spectropolarimetery in any three spectral regions from 380 to 900 nm. The ViSP instrument will be the highest precision spectropolarimeter ever produced with a spatial resolution of approximately 40 km at 600 nm and temporal resolution of 10s to achieve 1e-03 polarimetric precision. The Visible Tunable Filter (VTF) instrument under fabrication at the Kiepenheuer Institute for Solar Physics (KIS) is a triple-etalon Fabry-Perot imaging spectropolarimeter instrument capable of diffraction limited measurements of the Fe I 630.2 nm and Ca II 854.2 nm spectral lines for Doppler and magnetic measurements in the photosphere and chromosphere, respectively. The VTF will also enable the highest spatial and temporal resolution observations yet achieved in the H-alpha line for detailed studies of chromospheric dynamics in response to photospheric magnetic drivers. The Diffraction-Limited Near-IR Spectropolarimeter (DL-NiRSP) and the Cryogenic Near-IR Spectropolarimeter (Cryo-NiRSP) instruments, both under fabrication at the University of Hawaii, will enable polarimetric and spectroscopic investigations in the largely unexplored infra-red spectral region. The DL-NiRSP will span 900 nm to 2.5 microns in wavelength and include a novel fiber-optic "Integral Field Unit" (IFU) for true imaging spectropolarimetry in three simultaneous spectral regions over a variable field of view. This instrument will enable revolutionary measurements of prominence magnetic fields and will also, in the wider field mode, enable coronal polarimetric studies. The Cryo-NiRSP instrument spans the 1--5 micron wavelength range and will make near-diffraction limited 0.3" resolution slit-scan measurements of the coronal magnetic field out to 1.3 solar radii with temporal resolution measured in minutes. The DKIST facility will undergo extensive polarimetric calibration to ensure that the ultimate goal of 5e-04 polarimetic precision is obtainable under the best conditions. All of the data from the DKIST will be transmitted to the central DKIST data center in Boulder, Colorado where automated reduction and calibration pipelines will rapidly provide the community with calibrated data products for use in science investigations. The DKIST will also be operated in a "Service Mode" access model in which investigators will not be required to travel to the telescope to accomplish their science observations.

  8. Distributed aperture active imaging

    Microsoft Academic Search

    Joseph C. Marron; Richard L. Kendrick

    2007-01-01

    With a distributed aperture imaging system, one creates a large imaging aperture by combining the light from a series of distributed telescopes. In doing this, one can construct a fine-resolution imaging system with reduced volume. In this paper we present work on distributed aperture, active imaging systems that use coherent detection and digital image formation. In such a system, the

  9. A Large Sparse Aperture Densified Pupil Hypertelescope Concept for Ground Based Detection of Extra-Solar Earth-Like Planets

    NASA Technical Reports Server (NTRS)

    Gezari, D.; Lyon, R.; Woodruff, R.; Labeyrie, A.; Oegerle, William (Technical Monitor)

    2002-01-01

    A concept is presented for a large (10 - 30 meter) sparse aperture hyper telescope to image extrasolar earth-like planets from the ground in the presence of atmospheric seeing. The telescope achieves high dynamic range very close to bright stellar sources with good image quality using pupil densification techniques. Active correction of the perturbed wavefront is simplified by using 36 small flat mirrors arranged in a parabolic steerable array structure, eliminating the need for large delat lines and operating at near-infrared (1 - 3 Micron) wavelengths with flats comparable in size to the seeing cells.

  10. Multi-conjugate AO for the European Solar Telescope

    NASA Astrophysics Data System (ADS)

    Montilla, I.; Béchet, C.; Le Louarn, M.; Tallon, M.; Sánchez-Capuchino, J.; Collados Vera, M.

    2012-07-01

    The European Solar Telescope (EST) will be a 4-meter diameter world-class facility, optimized for studies of the magnetic coupling between the deep photosphere and upper chromosphere. It will specialize in high spatial resolution observations and therefore it has been designed to incorporate an innovative built-in Multi-Conjugate Adaptive Optics system (MCAO). It combines a narrow field high order sensor that will provide the information to correct the ground layer and a wide field low order sensor for the high altitude mirrors used in the MCAO mode. One of the challenging particularities of solar AO is that it has to be able to correct the turbulence for a wide range of observing elevations, from zenith to almost horizon. Also, seeing is usually worse at day-time, and most science is done at visible wavelengths. Therefore, the system has to include a large number of high altitude deformable mirrors. In the case of the EST, an arrangement of 4 high altitude DMs is used. Controlling such a number of mirrors makes it necessary to use fast reconstruction algorithms to deal with such large amount of degrees of freedom. For this reason, we have studied the performance of the Fractal Iterative Method (FriM) and the Fourier Transform Reconstructor (FTR), to the EST MCAO case. Using OCTOPUS, the end-to-end simulator of the European Southern Observatory, we have performed several simulations with both algorithms, being able to reach the science requirement of a homogeneous Strehl higher that 50% all over the 1 arcmin field of view.

  11. ATST telescope pier

    NASA Astrophysics Data System (ADS)

    Jeffers, Paul; Manuel, Eric; Dreyer, Oliver; Kärcher, Hans

    2012-09-01

    The Advanced Technology Solar Telescope (ATST) will be the largest solar telescope in the world with a 4m aperture primary mirror. The off axis nature of the telescope optical layout, has the proportions of an 8 metre class telescope. Accordingly the instrumentation for solar observations a 16m diameter co-rotating laboratory (Coude Rotator) is also located within the telescope pier. The pier has a lower cylindrical profile with an upper conical section to support both the telescope mount with a 9m bearing diameter and contain the 16m diameter Coudé rotator. The performance of this pier cannot be considered in isolation but must account for ancillary equipment, access and initial installation. The Coude rotator structure and bearing system are of similar size to the telescope base structure and therefore this is the proverbial 'ship in a bottle' problem. This paper documents the competing requirements on the pier design and the balancing of these as the design progresses. Also summarized is the evolution of the design from a conceptual traditional reinforced concrete pier to a composite concrete and steel framed design. The stiffness requirements of the steel frame was a unique challenge for both the theoretical performance and overall design strategy considering constructability. The development of design acceptance criteria for the pier is discussed along with interfacing of the AandE firm responsible for the pier design and the telescope designer responsible for the telescope performance.

  12. The large solar vacuum telescope: The optical system, and first spectral observations

    Microsoft Academic Search

    V. I. Skomorovsky; N. M. Firstova

    1996-01-01

    The performance of the optics of the Large Solar Vacuum Telescope (LSVT) and examples of the spectrograms taken with the spectrograph are presented. A new pneumo-mechanical support system for the siderostat mirror and monitoring system of the telescope optics is described.

  13. Large bearings with incorporated gears, high stiffness and precision for the Swedish Solar Telescope (SST) on La Palma

    E-print Network

    Rutten, Rob

    Telescope (SST) on La Palma SPIE vol. 6273, Optomechanical Technologies for Astronomy, paper 119, 2006 Solar Telescope (SST) obtains images of the solar surface with an unprecedented resolution of 0.1 arcsec, seeing, telescope optics 1. INTRODUCTION The SST1 is located at the Observatorio del Roque de los

  14. Opportunities for Follow-Up Observations of Solar System Objects with 50/70 cm Schmidt Telescope

    E-print Network

    Boyer, Edmond

    Opportunities for Follow-Up Observations of Solar System Objects with 50/70 cm Schmidt Telescope, akostov@astro.bas.bg Introduction The 50/70 cm Schmidt telescope is one of the four telescopes in National are obtained every clear dark night, for exceptional events moon nights are used, also. Telescopes schedules

  15. Concept of a 60-cm domeless solar telescope

    Microsoft Academic Search

    C. Kuehne

    1978-01-01

    The design and operating characteristics of the new 60-cm domeless tower telescope at the observatory of the University of Kyoto are described. Attention is given to such functions of the telescope as monochromatic spectroscopy and magnetography, spectroheliography, simultaneous polychromatic spectrography of transient phenomena, and photography in H-alpha light and in integral light; such design features as the optical system, tower

  16. DOT++: The Dutch Open Telescope with 1.4-m aperture Felix C.M. Bettonvil*a,b

    E-print Network

    Rutten, Rob

    as transversal pupil shift introducing the possibility to use obstruction free apertures up to 65cm. The design for removing atmospheric turbulence 6 . The resulting DOT movies are world famous (see the DOT-website http details visible have a resolution of 0.2", corresponding to 140km. For more DOT images and movies s

  17. SUAVE: a UV telescope for space weather and solar variability studies

    NASA Astrophysics Data System (ADS)

    Damé, L.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Keckhut, P.; Quémerais, E.

    2014-07-01

    SUAVE (Solar Ultraviolet Advanced Variability Experiment) is a far ultraviolet (FUV) imaging solar telescope of novel design for ultimate thermal stability and long lasting performances. SUAVE is a 90 mm Ritchey- Chrétien telescope with SiC (Silicon Carbide) mirrors and no entrance window for long and uncompromised observations in the UV (no coatings of mirrors, flux limited to less than a solar constant on filters to avoid degradation), associated with an ultimate thermal control (heat evacuation, focus control, stabilization). Design of the telescope and early thermal modeling leading to a representative breadboard (a R and T program supported by CNES) will be presented. SUAVE is the main instrument of the SUITS (Solar Ultraviolet Influence on Troposphere/Stratosphere) microsatellite mission, a small-size mission proposed to CNES and ESA.

  18. The Galactic Exoplanet Survey Telescope: A Proposed Space-Based Microlensing Survey for Terrestrial Extra-Solar Planets

    E-print Network

    David P. Bennett; Sun Hong Rhie

    2000-03-08

    We present a conceptual design for a space based Galactic Exoplanet Survey Telescope (GEST) which will use the gravitational microlensing technique to detect extra solar planets with masses as low as that of Mars at all separations >~ 1 AU. The microlensing data would be collected by a diffraction limited, wide field imaging telescope of ~ 1.5m aperture equipped with a large array of red-optimized CCD detectors. Such a system would be able to monitor $\\sim 2\\times 10^8$ stars in $\\sim 6$ square degrees of the Galactic bulge at intervals of 20-30 minutes, and it would observe $\\sim 12000$ microlensing events in three bulge seasons. If planetary systems like our own are common, GEST should be able to detect $\\sim 5000$ planets over a 2.5 year lifetime. If gas giants like Jupiter and Saturn are rare, then GEST would detect $\\sim 1300$ planets in a 2.5 year mission if we assume that most planetary systems are dominated by planets of about Neptune's' mass. Such a mission would also discover $\\sim 100$ planets of an Earth mass or smaller if such planets are common. This is a factor of $\\sim 50$ better than the most ambitious ground based programs that have been proposed. GEST will also be sensitive to planets which have been separated from their parent stars.

  19. Data from the Precision Solar Photometric Telescope (PSPT) in Hawaii from March 1998 to March 1999

    Microsoft Academic Search

    Oran R. White; Peter A. Fox; Randy Meisner; Mark P. Rast; Eric Yasukawa; Koon Darryl; Crystal Rice; Haosheng Lin; Jeff Kuhn; Roy Coulter

    \\u000a Two Precision Solar Photometric Telescopes (PSPT) designed and built at the U.S. National Solar Observatory (NSO) are in operation\\u000a in Rome and Hawaii. A third PSPT is now in operation the NSO at Sunspot, NM. The PSPT system records full disk solar images\\u000a at three wavelengths: K line at 393.3 nm and two continua at 409 nm and 607 nm

  20. Data From the Precision Solar Photometric Telescope (Pspt) in Hawaii From March 1998 to March 1999

    Microsoft Academic Search

    Oran R. White; Peter A. Fox; Randy Meisner; Mark P. Rast; Eric Yasukawa; Darryl Koon; Crystal Rice; Haosheng Lin; Jeff Kuhn; Roy Coulter

    2000-01-01

    Two Precision Solar Photometric Telescopes (PSPT) designed and built at the U.S. National Solar Observatory (NSO) are in operation in Rome and Hawaii. A third PSPT is now in operation the NSO at Sunspot, NM. The PSPT system records full disk solar images at three wavelengths: K line at 393.3 nm and two continua at 409 nm and 607 nm throughout the observing

  1. Filters for soft X-ray solar telescopes

    NASA Technical Reports Server (NTRS)

    Spiller, Eberhard; Grebe, Kurt; Golub, Leon

    1990-01-01

    Soft X-ray telescopes require filters that block visible and infrared light and have good soft X-ray transmission. The optical properties of possible materials are discussed, and the fabrication and testing methods for the filters used in a 10-inch normal incidence telescope for 63 A are described. The best performances in the 44-114-A wavelength range are obtained with foils of carbon and rhodium.

  2. 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.

  3. ATST telescope mount: telescope of machine tool

    NASA Astrophysics Data System (ADS)

    Jeffers, Paul; Stolz, Günter; Bonomi, Giovanni; Dreyer, Oliver; Kärcher, Hans

    2012-09-01

    The Advanced Technology Solar Telescope (ATST) will be the largest solar telescope in the world, and will be able to provide the sharpest views ever taken of the solar surface. The telescope has a 4m aperture primary mirror, however due to the off axis nature of the optical layout, the telescope mount has proportions similar to an 8 meter class telescope. The technology normally used in this class of telescope is well understood in the telescope community and has been successfully implemented in numerous projects. The world of large machine tools has developed in a separate realm with similar levels of performance requirement but different boundary conditions. In addition the competitive nature of private industry has encouraged development and usage of more cost effective solutions both in initial capital cost and thru-life operating cost. Telescope mounts move relatively slowly with requirements for high stability under external environmental influences such as wind buffeting. Large machine tools operate under high speed requirements coupled with high application of force through the machine but with little or no external environmental influences. The benefits of these parallel development paths and the ATST system requirements are being combined in the ATST Telescope Mount Assembly (TMA). The process of balancing the system requirements with new technologies is based on the experience of the ATST project team, Ingersoll Machine Tools who are the main contractor for the TMA and MT Mechatronics who are their design subcontractors. This paper highlights a number of these proven technologies from the commercially driven machine tool world that are being introduced to the TMA design. Also the challenges of integrating and ensuring that the differences in application requirements are accounted for in the design are discussed.

  4. Direct imaging of extra-solar planets with stationary occultations viewed by a space telescope

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.

    1978-01-01

    The use of a telescope in space to detect planets outside the solar system by means of imaging at optical wavelengths is discussed. If the 'black' limb of the moon is utilized as an occulting edge, a hypothetical Jupiter-Sun system could be detected at a distance as great as 10 pc, and a signal-to-noise ratio of 9 could be achieved in less than 20 min with a 2.4 m telescope in space. An orbit for the telescope is proposed; this orbit could achieve a stationary lunar occultation of any star for a period of nearly two hours.

  5. STS-31 Hubble Space Telescope (HST) solar array (SA) mockup at MSFC, Alabama

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A close-up shot shows an extravehicular mobility unit (EMU)-suited astronaut inspecting a solar array (SA) on the Hubble Space Telescope (HST) mockup in the Neutral Buoyancy Simulator (NBS) at the Marshall Space Flight Center (MSFC) in Huntsville, Alabama. MSFC managed the design and development of the telescope. The weightlessness simulator was used to practice SA contingency procedures that might be used in space. Astronauts also practiced SA servicing missions in the simulator which they will perform on the telescope in space. The solar arrays which supply electrical power to the space telescope were developed and contributed by the European Space Agency (ESA). ESA's two prime contractors were British Aerospace in England and AEG in West Germany. The two wing-like solar arrays contain 48,000 solar cells. They convert the sun's energy to electricity during that portion of an orbit when they are exposed to sunlight. The power is stored in six batteries to support the telescope during

  6. The Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

    NASA Technical Reports Server (NTRS)

    Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B. C., Jr.; Allen, Max J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C.

    1992-01-01

    We have developed seven compact soft X-ray/EUV (XUV) multilayer coated and two compact FUV interference film coated Cassegrain and Ritchey-Chretien telescopes for a rocket borne observatory, the Multi-Spectral Solar Telescope Array. We report here on extensive measurements of the efficiency and spectral bandpass of the XUV telescopes carried out at the Stanford Synchrotron Radiation Laboratory.

  7. Solar Wind observations using the Mexican Array Radio Telescope (MEXART)

    NASA Astrophysics Data System (ADS)

    Romero-Hernandez, E.; Gonzalez-Esparza, A.; Villanueva, P.; Aguilar-Rodriguez, E.; Mejia-Ambriz, J. C.; Mexart

    2013-05-01

    The Mexican Array Radiotelescope (MEXART) is an instrument devoted to observations of radio sources to study large-scale structures in the solar wind employing the Interplanetary Scintillation (IPS) technique. We report recent IPS observations, from January to April of 2013, including an analysis of the scintillation index and the estimation of solar wind velocities for a set of radio sources. We track the first ICMEs registered by the MEXART. We are initiating a continuos operation for a complete monitoring of IPS radio sources that will complement solar wind studies based on in-situ observations.

  8. Impacts on Hubble Space Telescope solar arrays: discrimination between natural and man-made particles

    Microsoft Academic Search

    A. T. Kearsley; G. Drolshagen; J. A. M. McDonnell; J.-C. Mandeville; A. Moussi

    2004-01-01

    A Post-Flight Investigation was initiated by the European Space Agency to analyze impact fluxes on solar arrays of the Hubble Space Telescope (HST), exposed to space for 8.25 years at approximately 600 km altitude. The solar cells were deployed during servicing mission SM-1 (December 1993), and retrieved by shuttle orbiter Columbia in March 2002 (SM-3B). A sub-panel of 2 m2

  9. Extracting Information from the Data Flood of New Solar Telescopes: Brainstorming

    NASA Astrophysics Data System (ADS)

    Asensio Ramos, A.

    2012-12-01

    Extracting magnetic and thermodynamic information from spectropolarimetric observations is a difficult and time consuming task. The amount of science-ready data that will be generated by the new family of large solar telescopes is so large that we will be forced to modify the present approach to inference. In this contribution, I propose several possible ways that might be useful for extracting the thermodynamic and magnetic properties of solar plasmas from such observations quickly.

  10. The Soft X-ray Telescope for the SOLAR-A mission

    Microsoft Academic Search

    S. Tsuneta; L. Acton; M. Bruner; J. Lemen; W. Brown; R. Caravalho; R. Catura; S. Freeland; B. Jurcevich; M. Morrison; Y. Ogawara; T. Hirayama; J. Owens

    1991-01-01

    The Soft X-ray Telescope (SXT) of the SOLAR-A mission is designed to produce X-ray movies of flares with excellent angular and time resolution as well as full-disk X-ray images for general studies. A selection of thin metal filters provide a measure of temperature discrimination and aid in obtaining the wide dynamic range required for solar observing. The co-aligned SXT aspect

  11. The Siberian Solar Radio Telescope: the current state of the instrument, observations, and data

    Microsoft Academic Search

    V. V. Grechnev; S. V. Lesovoi; G. Ya. Smolkov; B. B. Krissinel; V. G. Zandanov; A. T. Altyntsev; N. N. Kardapolova; R. Y. Sergeev; A. M. Uralov; V. P. Maksimov; B. I. Lubyshev

    2003-01-01

    The Siberian Solar Radio Telescope (SSRT) is one of the world's largest solar radio heliographs. It commenced operation in\\u000a 1983, and since then has undergone several upgrades. The operating frequency of the SSRT is 5.7 GHz. Since 1992 the instrument\\u000a has had the capability to make one-dimensional scans with a high time resolution of 56 ms and an angular resolution of 15 arc sec.

  12. PET: a proton\\/electron telescope for studies of magnetospheric, solar, and galactic particles

    Microsoft Academic Search

    W. R. Cook; A. C. Cummings; J. R. Cummings; T. L. Garrard; B. Kecman; R. A. Mewaldt; R. S. Selesnick; E. C. Stone; D. N. Baker; T. T. von Rosenvinge; J. B. Blake; L. B. Callis

    1993-01-01

    The proton\\/electron telescope (PET) on SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) is designed to provide measurements of energetic electrons and light nuclei from solar, Galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from ~1 to ~30 MeV and H and He nuclei from ~20 to ~300 MeV\\/nucleon, with

  13. The daytime use of Adaptive Optics for solar and stellar Extremely Large Telescopes

    Microsoft Academic Search

    Jacques Beckers

    2002-01-01

    Now Single Conjugate Adaptive Optics (SCAO) has been successfully implemented on both nighttime and solar telescopes, there is a rapidly growing interest in developing, what will be the next step in astronomical adaptive optics, Multi-Conjugate Adaptive Optics (MCAO). MCAO aims at breaking the small field-of-view barrier inherent in SCAO. MCAO is considered an essential component for both future solar and

  14. The chemical composition of micrometeoroids impacting upon the solar arrays of the Hubble Space Telescope

    Microsoft Academic Search

    A. T. Kearsley; G. A. Graham; J. A. M. McDonnell; E. A. Taylor; G. Drolshagen; R. J. Chater; D. McPhail; M. J. Burchell

    2007-01-01

    Analytical scanning electron microscopy of solar cells returned from the Hubble Space Telescope (HST) at the end of HST Service Missions SM-1 (1993) and SM-3B (2002) has revealed abundant remains of micrometeoroids. We have documented the most common residue compositions, and in this paper we suggest how they relate to mineral phases, and show how it is possible to estimate

  15. On-orbit Performance of the Solar Optical Telescope aboard Hinode

    Microsoft Academic Search

    K. Ichimoto; Y. Katsukawa; T. Tarbell; R. A. Shine; C. Hoffmann; T. Berger; T. Cruz; Y. Suematsu; S. Tsuneta; T. Shimizu; B. W. Lites

    2008-01-01

    On-orbit performance of the Solar Optical Telescope (SOT) aboard Hinode is described with some attention to its unpredicted aspects. In general, SOT reveals an excellent performance and has been providing outstanding data. Some unexpected features exist, however, in behaviours of the focus position, throughput and structural stability. Most of them are recovered by the daily operation i.e., frequent focus adjustment,

  16. The Astrometric Imaging Telescope - A space-based observatory for extra-solar planet detection

    NASA Technical Reports Server (NTRS)

    Pravdo, Steven H.

    1991-01-01

    The paper describes the objectives, techniques, instrumentation, and mission of the planned Astrometric Imaging Telescope. This space-based observatory is designed to detect and characterize extra-solar planetary systems. Results will contribute to the understanding of the astrophysics of stellar and planetary formation and provide an impetus for the study of exobiology.

  17. Seeing the Deep Sky: Telescopic Astronomy Projects Beyond the Solar System

    NASA Astrophysics Data System (ADS)

    Schaaf, Fred

    1992-03-01

    Packed with a vast array of telescopic projects involving different kind of stars, star clusters, nebulae and galaxies which lie beyond our solar system. Takes a look at stars of diverse chemical or atomic ``brew'', old and new, tiny or vast, dense or tenuous; the ways in which they behave and much more.

  18. Detecting Life-bearing Extra-solar Planets with Space Telescopes

    E-print Network

    Beckwith, Steven V W

    2007-01-01

    One of the promising methods to search for life on extra-solar planets (exoplanets) is to detect life's signatures in their atmospheres. Spectra of exoplanet atmospheres at the modest resolution needed to search for oxygen, carbon dioxide, water, and methane will demand large collecting areas and large diameters to capture and isolate the light from planets in the habitable zones around the stars. For telescopes using coronagraphs to isolate the light from the planet, each doubling of telescope diameter will increase the available sample of stars by an order of magnitude, indicating a high scientific return if the technical difficulties of constructing very large space telescopes can be overcome. For telescopes detecting atmospheric signatures of transiting planets, the sample size increases only linearly with diameter, and the available samples are probably too small to guarantee detection of life-bearing planets. Using samples of nearby stars suitable for exoplanet searches, this paper shows that the demand...

  19. EIT: Solar corona synoptic observations from SOHO with an Extreme-ultraviolet Imaging Telescope

    NASA Technical Reports Server (NTRS)

    Delaboudiniere, J. P.; Gabriel, A. H.; Artzner, G. E.; Michels, D. J.; Dere, K. P.; Howard, R. A.; Catura, R.; Stern, R.; Lemen, J.; Neupert, W.

    1988-01-01

    The Extreme-ultraviolet Imaging Telescope (EIT) of SOHO (solar and heliospheric observatory) will provide full disk images in emission lines formed at temperatures that map solar structures ranging from the chromospheric network to the hot magnetically confined plasma in the corona. Images in four narrow bandpasses will be obtained using normal incidence multilayered optics deposited on quadrants of a Ritchey-Chretien telescope. The EIT is capable of providing a uniform one arc second resolution over its entire 50 by 50 arc min field of view. Data from the EIT will be extremely valuable for identifying and interpreting the spatial and temperature fine structures of the solar atmosphere. Temporal analysis will provide information on the stability of these structures and identify dynamical processes. EIT images, issued daily, will provide the global corona context for aid in unifying the investigations and in forming the observing plans for SOHO coronal instruments.

  20. Concept study of an Extremely Large Hyper Telescope (ELHyT) with 1200m sparse aperture for direct imaging at 100 micro-arcsecond resolution

    NASA Astrophysics Data System (ADS)

    Labeyrie, Antoine; Mourard, Denis; Allouche, Fatmé; Chakraborthy, Rijuparna; Dejonghe, Julien; Surya, Arun; Bresson, Yves; Aime, Claude; Mary, David; Carlotti, Alexis

    2012-07-01

    The hypertelescope construction initiated in the Southern Alps (Labeyrie et al., this conference) has provided some preliminary operating experience indicating that larger versions, up to perhaps 1200m, are probably feasible at suitable sites. The Arecibo-like architecture of such instruments does not require the large mount and dome which dominate the cost of a 40m ELT. For the same cost, an "Extremely Large Hyper Telescope” ( ELHyT) may therefore have a larger collecting area. It may thus in principle reach higher limiting magnitudes, both for seeing-limited and, if equipped with a Laser Guide Star and adaptive phasing, for high-resolution imaging with gain as the size ratio, i.e. about 30 with respect to a 40m ELT. Like the radio arrays of antennas, such instruments can be grown progressively. Also, they can be up-graded with several focal gondolas, independently tracking different sources. Candidate sites have been identified in the Himalaya and the Andes. We describe several design options and compare the science achievable for both instruments, ELTs and ELHyTs. The broad science addressed by an ELHyT covers stellar chromospheres, transiting exoplanets and those requiring a high dynamic range, achieved by array apodization or coronagraphy. With a Laser Guide Star, it extends to faint compact sources beyond the limits of telescopes having a smaller collecting area, supernovae, active galactic nuclei, gamma ray bursts. The sparse content of remote galaxies seen in the Hubble Deep Field appears compatible with the crowding limitations of an ELHyT having 1000 apertures.

  1. Detection of Solar Wind Disturbances: Mexican Array Radio Telescope IPS Observations at 140 MHz

    NASA Astrophysics Data System (ADS)

    Romero-Hernandez, E.; Gonzalez-Esparza, J. A.; Aguilar-Rodriguez, E.; Ontiveros-Hernandez, V.; Villanueva-Hernandez, P.

    2015-05-01

    The interplanetary scintillation (IPS) technique is a remote-sensing method for monitoring solar-wind perturbations. The Mexican Array Radio Telescope (MEXART) is a single-station instrument operating at 140 MHz, fully dedicated to performing solar-wind studies employing the IPS technique. We report MEXART solar-wind measurements (scintillation indices and solar-wind velocities) using data obtained during the 2013 and 2014 campaigns. These solar-wind measurements were calculated employing a new methodology based on the wavelet transform (WT) function. We report the variation of the scintillation indices versus the heliocentric distance for two IPS sources (3C48 and 3C147). We found different average conditions of the solar-wind density fluctuations in 2013 and 2014. We used the fittings of the radial dependence of the scintillation index to calculate g-indices. Based on the g-index value, we identified 17 events that could be associated with strong compression regions in the solar wind. We present the first ICME identifications in our data. We associated 14 IPS events with preceding CME counterparts by employing white-light observations from the Large Angle and Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO) spacecraft. We found that most of the IPS events, detected during the solar maximum of Cycle 24 were associated with complex CME events. For the IPS events associated with single CME counterparts, we found a deceleration tendency of the CMEs as they propagate in the interplanetary medium. These results show that the instrument detects solar-wind disturbances, and the WT methodology provides solar-wind information with good accuracy. The MEXART observations will complement solar-wind IPS studies using other frequencies, and the tracking of solar-wind disturbances by other stations located at different longitudes.

  2. The solar array-induced disturbance of the Hubble Space Telescope pointing system

    NASA Technical Reports Server (NTRS)

    Foster, C. L.; Tinker, M. L.; Nurre, G. S.; Till, W. A.

    1995-01-01

    The investigation of the vibrational disturbances of the Hubble Space Telescope that were discovered soon after deployment in orbit is described in detail. It was found that the disturbances were particularly evident during orbital day-night crossings, and that the magnitudes of the disturbances were considerably larger than the design jitter requirements. This paper describes the process by which the vibrations were characterized and isolated to a particular mechanism. The analysis of the flight data and comparisons with computer simulation results showed that the source of the disturbances was the thermally driven deformation of the solar arrays in conjunction with frictional effects in the array mechanisms. The control system was successfully modified to attenuate the disturbances to tolerable levels pending mechanical and thermal redesign of the solar arrays. The new arrays were installed during the first space telescope servicing mission and, in combination with the enhanced control system algorithm, reduced the disturbances to satisfactory levels.

  3. Solar-Array-Induced Disturbance of the Hubble Space Telescope Pointing System

    NASA Technical Reports Server (NTRS)

    Foster, Carlton L.; Tinker, Michael L.; Nurre, Gerald S.; Till, William A.

    1995-01-01

    The investigation of the vibrational disturbances of the Hubble Space Telescope that were discovered soon after deployment in orbit is described in detail. It was found that the disturbances were particularly evident during orbital day-night crossings, and that the magnitude of the disturbances was considerably larger than the design jitter requirement. This paper describes the process by which the vibrations were characterized and isolated to a particular mechanism. The analysis of the flight data and comparisons with computer simulation results showed that the source of the disturbances was the thermally driven deformation of the solar arrays in conjunction with frictional effects in the array mechanisms. The control system was successfully modified to attenuate the disturbances to tolerable levels pending mechanical and thermal redesign of the solar arrays. The new arrays were installed during the first Space Telescope servicing mission, and in combination with the enhanced control system algorithm reduced the disturbances to satisfactory levels.

  4. X-ray photographs of a solar active region with a multilayer telescope at normal incidence

    NASA Technical Reports Server (NTRS)

    Underwood, J. H.; Bruner, M. E.; Haisch, B. M.; Brown, W. A.; Acton, L. W.

    1987-01-01

    An astronomical photograph was obtained with a multilayer X-ray telescope. A 4-cm tungsten-carbon multilayer mirror was flown as part of an experimental solar rocket payload, and successful images were taken of the sun at normal incidence at a wavelength of 44 A. Coronal Si XII emission from an active region was recorded on film; as expected, the structure is very similar to that observed at O VIII wavelengths by the Solar Maximum Mission flat-crystal spectrometer at the same time. The small, simple optical system used in this experiment appears to have achieved a resolution of 5 to 10 arcsec.

  5. Multi-purpose grating spectrograph for the 4-meter European Solar Telescope

    NASA Astrophysics Data System (ADS)

    Calcines, A.; Collados, M.; Feller, A.; Gelly, B.; Grauf, B.; Hirzberger, J.; López Ariste, A.; Lopez, R. L.; Mein, P.; Sayéde, F.

    2012-09-01

    This communication presents a family of spectrographs designed for the European Solar Telescope. They can operate in four different configurations: a long slit standard spectrograph (LsSS), two devices based on subtractive double pass (TUNIS and MSDP) and one based on an integral field, multi-slit, multi-wavelength configuration. The combination of them composes the multi-purpose grating spectrograph of EST, focused on supporting the different science cases of the solar photosphere and chromosphere in the spectral range from 3900 Ĺ to 23000 Ĺ. The different alternatives are made compatible by using the same base spectrographs and different selectable optical elements corresponding to specific subsystems of each configuration.

  6. Features of the solar array drive mechanism for the space telescope

    NASA Technical Reports Server (NTRS)

    Hostenkamp, R. G.

    1985-01-01

    The solar array drive mechanism for the Space Telescope embodies several features not customarily found on solar array drives. Power and signal transfer is achieved by means of a flexible wire harness for which the chosen solution, consisting of 168 standard wires, is described. The torque performance data of the harness over its temperature range are presented. The off load system which protects the bearings from the launch loads is released by a trigger made from Nitinol, the memory alloy. The benefits of memory alloy and the caveats for the design are briefly discussed. The design of the off load system is described and test experience is reported.

  7. The Robotically Controlled Telescope and the Search for Extra-Solar Planets

    NASA Astrophysics Data System (ADS)

    Davis, D. R.; Howell, S. B.; Everett, M. E.; Gelderman, R.; Guinan, E.; Mattox, J. R.; McGruder, C. H.; Walter, D. K.

    2003-05-01

    The 1.3 m telescope on Kitt Peak has been refurbished by the Robotically Controlled Telescope (RCT) consortium (Western Kentucky University, Planetary Science Institute, South Carolina State University, and Villanova University). This telescope will be operated as a robotically controlled observatory where the observing parameters for various science programs are entered into a master scheduler which then carries out the observations in an optimal fashion. The scheduler allows for rapid response to transient events such as Gamma-ray bursters, CV flares or AGN eruptions. The consortium plans to commence a full program of science and educational activities beginning in the fall, 2003. High-precision photometry is one of the principal capabilities of this telescope and we anticipate carrying out a photometric search for extra-solar planets as one of the main science programs. Photometric precision of 1 mmag per 180-sec exposure has been demonstrated in preliminary tests. The photometric capabilities and extra-solar planet search strategy for the RCT will be presented. Refurbishment of the RCT has been made possible by NASA grant NAG5-8762.

  8. The chemistry of micrometeoroid and space debris remnants captured on hubble space telescope solar cells

    Microsoft Academic Search

    G. A. Graham; N. McBride; A. T. Kearsley; G. Drolshagen; S. F. Green; J. A. M. McDonnell; M. M. Grady; I. P. Wright

    2001-01-01

    Prior to the retrieval in 1993 from low Earth orbit (LEO), the “—V2” Solar Array wing of the Hubble Space Telescope was exposed to hypervelocity impacts (micrometre to millimetre scale) from both micrometeoroids and space debris. The initial survey of the damage (100–3500?m diameter sized craters) identified that micrometeoroid remnants dominated the flux in the 100–1000?m size regime, with debris

  9. The Hard X-ray Telescope (HXT) for the SOLAR-A mission

    Microsoft Academic Search

    T. Kosugi; K. Makishima; T. Murakami; T. Sakao; T. Dotani; M. Inda; K. Kai; S. Masuda; H. Nakajima; Y. Ogawara; M. Sawa; K. Shibasaki

    1991-01-01

    The Hard X-ray Telescope (HXT) is a Fourier-synthesis imager; a set of spatially-modulated photon count data are taken from 64 independent subcollimators and are Fourier-transformed into an image by using procedures such as the maximum entropy method (MEM) or CLEAN. The HXT takes images of solar flares simultaneously in four energy bands, nominally 15 (or 19)–24, 24–35, 35–57, and 57–100

  10. Prototype tests for the CELESTE solar array gamma-ray telescope.

    NASA Astrophysics Data System (ADS)

    Giebels, B.; Bazer-Bachi, R.; Bergeret, H.; Cordier, A.; Debiais, G.; Denaurois, M.; Dezalay, J. P.; Dumora, D.; Eschstruth, P.; Espigat, P.; Fabre, B.; Fleury, P.; Ghesquiere, C.; Herault, N.; Malet, I.; Merkel, B.; Meynadier, C.; Palatka, M.; Pare, E.; Procureur, J.; Punch, M.; Quebert, J.; Ragan, K.; Rob, L.; Schovanek, P.; Smith, D. A.; Vrana, J.

    1998-08-01

    The CELESTE experiment will be an atmospheric Cherenkov detector designed to bridge the gap in energy sensitivity between current satellite and ground-based gamma-ray telescopes, 20 - 300 GeV. The authors present test results made at the former solar power plant, Themis, in the French Pyrenees. The tests confirm the viability of using a central tower heliostat array for Cherenkov wavefront sampling.

  11. Tilt-correction adaptive optical system for solar telescope of Nanjing University

    Microsoft Academic Search

    Chang-Hui Rao; Wen-Han Jiang; Cheng Fang; Ning Ling; Wei-Chao Zhou; Ming-De Ding; Xue-Jun Zhang; Dong-Hong Chen; Mei Li; Xiu-Fa Gao; Tian Mi

    2003-01-01

    A tilt-correction adaptive optical system installed at 430mm Solar Telescope at Nanjing University has been in operation. It is made up of a tip-tile mirror, a correlation tracker and an imaging CCD camera. The Absolute Difference algorithm is used in order to detect image motion in the correlation tracker. The sampling frequency of the system is 419Hz. In this paper,

  12. Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

    NASA Technical Reports Server (NTRS)

    Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B.; Allen, Maxwell J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C., Jr.

    1991-01-01

    The Multispectral Solar Telescope Array is a rocket-borne observatory which encompasses seven compact soft X-ray/EUV, multilayer-coated, and two compact far-UV, interference film-coated, Cassegrain and Ritchey-Chretien telescopes. Extensive measurements are presented on the efficiency and spectral bandpass of the X-ray/EUV telescopes. Attention is given to systematic errors and measurement errors.

  13. Detecting Life-bearing Extra-solar Planets with Space Telescopes

    E-print Network

    Steven V. W. Beckwith

    2008-03-29

    One of the promising methods to search for life on extra-solar planets (exoplanets) is to detect life's signatures in their atmospheres. Spectra of exoplanet atmospheres at the modest resolution needed to search for oxygen, carbon dioxide, water, and methane will demand large collecting areas and large diameters to capture and isolate the light from planets in the habitable zones around the stars. For telescopes using coronagraphs to isolate the light from the planet, each doubling of telescope diameter will increase the available sample of stars by an order of magnitude, indicating a high scientific return if the technical difficulties of constructing very large space telescopes can be overcome. For telescopes detecting atmospheric signatures of transiting planets, the sample size increases only linearly with diameter, and the available samples are probably too small to guarantee detection of life-bearing planets. Using samples of nearby stars suitable for exoplanet searches, this paper shows that the demands of searching for life with either technique will require large telescopes, with diameters of order 10m or larger in space.

  14. Photogrammetric Assessment of the Hubble Space Telescope Solar Arrays During the Second Servicing Mission

    NASA Technical Reports Server (NTRS)

    Sapp, C. A.; Dragg, J. L.; Snyder, M. W.; Gaunce, M. T.; Decker, J. E.

    1998-01-01

    This report documents the photogrammetric assessment of the Hubble Space Telescope (HST) solar arrays conducted by the NASA c Center Image Science and Analysis Group during Second Servicing Mission 2 (SM-2) on STS-82 in February 1997. Two type solar array analyses were conducted during the mission using Space Shuttle payload bay video: (1) measurement of solar array motion due to induced loads, and (2) measurement of the solar array static or geometric twist caused by the cumulative array loading. The report describes pre-mission planning and analysis technique development activities conducted to acquire and analyze solar array imagery data during SM-2. This includes analysis of array motion obtained during SM-1 as a proof-of-concept of the SM-2 measurement techniques. The report documents the results of real-time analysis conducted during the mission and subsequent analysis conducted post-flight. This report also provides a summary of lessons learned on solar array imagery analysis from SM-2 and recommendations for future on-orbit measurements applicable to HST SM-3 and to the International Space Station. This work was performed under the direction of the Goddard Space Flight Center HST Flight Systems and Servicing Project.

  15. High-performance parallel image reconstruction for the New Vacuum Solar Telescope

    NASA Astrophysics Data System (ADS)

    Li, Xue-Bao; Liu, Zhong; Wang, Feng; Jin, Zhen-Yu; Xiang, Yong-Yuan; Zheng, Yan-Fang

    2015-06-01

    Many technologies have been developed to help improve spatial resolution of observational images for ground-based solar telescopes, such as adaptive optics (AO) systems and post-processing reconstruction. As any AO system correction is only partial, it is indispensable to use post-processing reconstruction techniques. In the New Vacuum Solar Telescope (NVST), a speckle-masking method is used to achieve the diffraction-limited resolution of the telescope. Although the method is very promising, the computation is quite intensive, and the amount of data is tremendous, requiring several months to reconstruct observational data of one day on a high-end computer. To accelerate image reconstruction, we parallelize the program package on a high-performance cluster. We describe parallel implementation details for several reconstruction procedures. The code is written in the C language using the Message Passing Interface (MPI) and is optimized for parallel processing in a multiprocessor environment. We show the excellent performance of parallel implementation, and the whole data processing speed is about 71 times faster than before. Finally, we analyze the scalability of the code to find possible bottlenecks, and propose several ways to further improve the parallel performance. We conclude that the presented program is capable of executing reconstruction applications in real-time at NVST.

  16. Reflectivity, polarization properties, and durability of metallic mirror coatings for the European Solar Telescope

    NASA Astrophysics Data System (ADS)

    Feller, A.; Krishnappa, N.; Pleier, O.; Hirzberger, J.; Jobst, P. J.; Schürmann, M.

    2012-09-01

    In the context of the conceptual design study for the European Solar Telescope (EST) we have investigated different metallic mirror coatings in terms of reflectivity, polarization properties and durability. Samples of the following coating types have been studied: bare aluminum, silver with different dielectric layers for protection and UV enhancement, and an aluminum-silver combination. From 2009 to 2011 we have carried out a long-term durability test under realistic observing conditions at the VTT solar telescope of the Observatorio del Teide (Tenerife, Spain), accompanied by repeated reflectivity measurements in the EST spectral working range (0.3 - 20 ?m), and by polarization measurements in the visible range. The test results allow us to find the optimum coatings for the different mirrors in the EST beampath and to eventually assess aging effects and re-coating cycles. The results of the polarization measurements are a valuable input for an EST telescope polarization model, helping to meet the stringent requirements on polarimetric accuracy.

  17. The Kilodegree Extremely Little Telescope (KELT): A Small Robotic Telescope for Large-Area Synoptic Surveys

    E-print Network

    Joshua Pepper; Richard W. Pogge; D. L. DePoy; J. L. Marshall; K. Z. Stanek; Amelia M. Stutz; Shawn Poindexter; Robert Siverd; Thomas P. O'Brien; Mark Trueblood; Patricia Trueblood

    2007-07-30

    The Kilodegree Extremely Little Telescope (KELT) project is a survey for planetary transits of bright stars. It consists of a small-aperture, wide-field automated telescope located at Winer Observatory near Sonoita, Arizona. The telescope surveys a set of 26 x 26 degree fields, together covering about 25% of the Northern sky, targeting stars in the range of 8solar-type main sequence stars.

  18. MAST: a mass spectrometer telescope for studies of the isotopic composition of solar, anomalous, and galactic cosmic ray nuclei

    Microsoft Academic Search

    W. R. Cook; A. C. Cummings; J. R. Cummings; T. L. Garrard; B. Kecman; R. A. Mewaldt; R. S. Selesnick; E. C. Stone; T. T. von Rosenvinge

    1993-01-01

    The mass spectrometer telescope (MAST) on SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) is designed to provide high-resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z=2 to 28) over the energy range from ~10 to several hundred MeV\\/nucleon. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly

  19. The thermal environment of the fiber glass dome for the new solar telescope at Big Bear Solar Observatory

    NASA Astrophysics Data System (ADS)

    Verdoni, A. P.; Denker, C.; Varsik, J. R.; Shumko, S.; Nenow, J.; Coulter, R.

    2007-09-01

    The New Solar Telescope (NST) is a 1.6-meter off-axis Gregory-type telescope with an equatorial mount and an open optical support structure. To mitigate the temperature fluctuations along the exposed optical path, the effects of local/dome-related seeing have to be minimized. To accomplish this, NST will be housed in a 5/8-sphere fiberglass dome that is outfitted with 14 active vents evenly spaced around its perimeter. The 14 vents house louvers that open and close independently of one another to regulate and direct the passage of air through the dome. In January 2006, 16 thermal probes were installed throughout the dome and the temperature distribution was measured. The measurements confirmed the existence of a strong thermal gradient on the order of 5° Celsius inside the dome. In December 2006, a second set of temperature measurements were made using different louver configurations. In this study, we present the results of these measurements along with their integration into the thermal control system (ThCS) and the overall telescope control system (TCS).

  20. Results of protective coating studies for the Hubble Space Telescope solar array

    NASA Technical Reports Server (NTRS)

    Linton, Roger C.; Gause, Raymond L.; Harwell, Roger J.; Dehaye, Robert F.; Burns, Howard Dewitt, Jr.; Reynolds, J. M.

    1989-01-01

    An account is given of the methods, results, and interpretive conclusions obtained by a series of comprehensive performance verification/qualification tests conducted on candidate coatings for the Hubble Space Telescope's (HST) solar array. These coatings are intended to minimize the effects of orbital atomic oxygen impingement on exposed materials. Attention was given to atomic oxygen exposure, UV exposure, thermal cycling, and electron and proton exposure. The V-10 and CVI-1140-1 candidate coatings were demonstrated to be adequately resistant to a five-year HST mission's environmental exposure.

  1. The ability of the space telescope to detect extra-solar planetary systems

    NASA Technical Reports Server (NTRS)

    Baum, W. A.

    1979-01-01

    The space telescope can plan a key role in searching for and investigating the contents of extra-solar planetary systems. For about 90 nearby stars, positional variations due to major planets would be well within the astrometric capability of the wide-field/planetary camera system. Since the centroids of star images will be determined to within a milliarcsecond down to 22d magnitude, there will be an abundance of reference stars at very small angular distances from each planetary system candidate, and they will have small enough motions of their own to provide a reference frame of the stability required.

  2. The multi-conjugate adaptive optics system of the New Solar Telescope at Big Bear Solar Observatory

    NASA Astrophysics Data System (ADS)

    Schmidt, Dirk; Gorceix, Nicolas; Zhang, Xianyu; Marino, Jose; Coulter, Roy; Shumko, Sergey; Goode, Phil; Rimmele, Thomas; Berkefeld, Thomas

    2014-07-01

    We report on the multi-conjugate adaptive optics (MCAO) system of the New Solar Telescope (NST) at Big Bear Solar Observatory which has been integrated in October 2013 and is now available for MCAO experiments. The NST MCAO system features three deformable mirrors (DM), and it is purposely flexible in order to offer a valuable facility for development of solar MCAO. Two of the deformable mirrors are dedicated to compensation of field dependent aberrations due to high-altitude turbulence, whereas the other deformable mirror compensates field independent aberrations in a pupil image. The opto-mechanical design allows for changing the conjugate plane of the two high-altitude DMs independently between two and nine kilometers. The pupil plane DM can be placed either in a pupil image upstream of the high-altitude DMs or downstream. This capability allows for performing experimental studies on the impact of the geometrical order of the deformable mirrors and the conjugate position. The control system is flexible, too, which allows for real-world analysis of various control approaches. This paper gives an overview of the NST MCAO system and reveals the first MCAO corrected image taken at Big Bear Solar Observatory.

  3. Solar-B X-ray Telescope (XRT) Concept Study Report

    NASA Technical Reports Server (NTRS)

    Golub, Leon

    1999-01-01

    The X-ray observations from the Yohkoh SXT provided the greatest step forward in our understanding of the solar corona in nearly two decades. Expanding on the accomplishments of Yohkoh, we believe that the scientific objectives of the Solar-B mission are achieved with a significantly improved X-ray telescope (XRT) similar to the SXT. The Solar-B XRT will have twice the spatial resolution and a broader temperature response, while building on the knowledge gained from the successful Yohkoh mission. We present the scientific justification for this view, discuss the instrumental requirements that flow from the scientific objectives, and describe the instrumentation to meet these requirements. We then provide a detailed discussion of the design activities carried out during Phase A, noting the conclusions that were reached in terms of their implications for the detailed design activities which are now commencing. Details of the instrument that have changed as a result of the Phase A studied are specifically noted, and areas of concern going into Phase B are highlighted. XRT is a grazing-incidence (GI) modified Wolter I X-ray telescope, of 35cm inner diameter and 2.7m focal length. The 2048x2048 back-illuminated CCD (now an ISAS responsibility) has 13.5 micron pixels, corresponding to 1.0 arcsec and giving full Sun field of view. This will be the highest resolution GI X-ray telescope ever flown for Solar coronal studies, and it has been designed specifically to observe both the high and low temperature coronal plasma. A small optical telescope provides visible light images for co-alignment with the Solar-B optical and EUV instruments. The XRT science team is working in close cooperation with our Japanese colleagues in the design and construction of this instrument. All of the expertise and resources of the High Energy and Solar/Stellar Divisions of the Center for Astrophysics are being made available to this program, and our team will carry its full share of responsibility for mission operations, data reduction and education and public outreach. All aspects of the XRT design were reviewed during Phase A. The study focussed particularly on those aspects that have the greatest affect on instrument performance and extended lifetime, on the image quality error budget, and on the camera (mechanical and electrical) interface and the instrument mounting interfaces. The present instrument design differs in some details from that originally proposed. Selection of the XRT for Phase A study was contingent upon the removal of the camera and its associated electronics, and the acceptance of a stringent cost cap. The removal of the electronics left the XRT without control electronics for the instrument mechanisms. A mechanism controller was therefore added. The removal of the camera resulted in major complications to the integration and test plan. After many discussions, it was decided that the system would be less expensive, and the risk of unacceptable performance lower, if we include a focus mechanism. The remainder of the XRT design baseline matches the proposed configuration. Data requirements for the XRT are driven by the science plans, which are based on the physical processes in the solar outer atmosphere. Discussions to date of the XRT observing plan, both alone and in conjunction with the other Solar-B instruments, shows that the XRT needs 2 Gbits of on-board storage, at least one circulating buffer of 640 Mbits, and twelve 10- minute downlinks per day in order to carry out its required programs.

  4. The spectrometer telescope for imaging x-rays on board the Solar Orbiter mission

    NASA Astrophysics Data System (ADS)

    Benz, A. O.; Krucker, S.; Hurford, G. J.; Arnold, N. G.; Orleanski, P.; Gröbelbauer, H.-P.; Klober, S.; Iseli, L.; Wiehl, H. J.; Csillaghy, A.; Etesi, L.; Hochmuth, N.; Battaglia, M.; Bednarzik, M.; Resanovic, R.; Grimm, O.; Viertel, G.; Commichau, V.; Meuris, A.; Limousin, O.; Brun, S.; Vilmer, N.; Skup, K. R.; Graczyk, R.; Stolarski, M.; Michalska, M.; Nowosielski, W.; Cichocki, A.; Mosdorf, M.; Seweryn, K.; Przepiórka, A.; Sylwester, J.; Kowalinski, M.; Mrozek, T.; Podgorski, P.; Mann, G.; Aurass, H.; Popow, E.; Onel, H.; Dionies, F.; Bauer, S.; Rendtel, J.; Warmuth, A.; Woche, M.; Plüschke, D.; Bittner, W.; Paschke, J.; Wolker, D.; Van Beek, H. F.; Farnik, F.; Kasparova, J.; Veronig, A. M.; Kienreich, I. W.; Gallagher, P. T.; Bloomfield, D. S.; Piana, M.; Massone, A. M.; Dennis, B. R.; Schwarz, R. A.; Lin, R. P.

    2012-09-01

    The Spectrometer Telescope for Imaging X-rays (STIX) is one of 10 instruments on board Solar Orbiter, a confirmed Mclass mission of the European Space Agency (ESA) within the Cosmic Vision program scheduled to be launched in 2017. STIX applies a Fourier-imaging technique using a set of tungsten grids (at pitches from 0.038 to 1 mm) in front of 32 pixelized CdTe detectors to provide imaging spectroscopy of solar thermal and non-thermal hard X-ray emissions from 4 to 150 keV. The status of the instrument reviewed in this paper is based on the design that passed the Preliminary Design Review (PDR) in early 2012. Particular emphasis is given to the first light of the detector system called Caliste-SO.

  5. Feasibility study of a layer-oriented wavefront sensor for solar telescopes.

    PubMed

    Marino, Jose; Wöger, Friedrich

    2014-02-01

    Solar multiconjugate adaptive optics systems rely on several wavefront sensors, which measure the incoming turbulent phase along several field directions to produce a tomographic reconstruction of the turbulent phase. In this paper, we explore an alternative wavefront sensing approach that attempts to directly measure the turbulent phase present at a particular height in the atmosphere: a layer-oriented cross-correlating Shack-Hartmann wavefront sensor (SHWFS). In an experiment at the Dunn Solar Telescope, we built a prototype layer-oriented cross-correlating SHWFS system conjugated to two separate atmospheric heights. We present the data obtained in the observations and complement these with ray-tracing computations to achieve a better understanding of the instrument's performance and limitations. The results obtained in this study strongly indicate that a layer-oriented cross-correlating SHWFS is not a practical design to measure the wavefront at a high layer in the atmosphere. PMID:24514185

  6. The soft x-ray photon-counting telescope for solar observations

    NASA Astrophysics Data System (ADS)

    Sakao, Taro; Narukage, Noriyuki; Suematsu, Yoshinori; Watanabe, Kyoko; Shimojo, Masumi; Imada, Shinsuke; Ishikawa, Shin-nosuke; DeLuca, Edward E.

    2014-07-01

    We present overview and development activities of a soft X-ray photon-counting spectroscopic imager for the solar corona that we conceive as a possible scientific payload for future space solar missions including Japanese Solar-C. The soft X-ray imager will employ a Wolter I grazing-incidence sector mirror with which images of the corona (1 MK to beyond 10 MK) will be taken with the highest-ever angular resolution (0.5"/pixel for a focal length of 4 m) as a solar Xray telescope. In addition to high-resolution imagery, we attempt to implement photon-counting capability for the imager by employing a backside-illuminated CMOS image sensor as the focal-plane device. Imaging-spectroscopy of the X-ray corona will be performed for the first time in the energy range from ~0.5 keV up to 10 keV. The imaging-spectroscopic observations with the soft X-ray imager will provide a noble probe for investigating mechanism(s) of magnetic reconnection and generation of supra-thermal (non-thermal) electrons associated with flares. Ongoing development activities in Japan towards the photon-counting imager is described with emphasis on that for sub-arcsecond-resolution grazing-incidence mirrors.

  7. Photometry's bright future: Detecting Solar System analogues with future space telescopes

    E-print Network

    Hippke, Michael

    2015-01-01

    Time-series transit photometry from the Kepler space telescope has allowed for the discovery of thousands of exoplanets. We explore the potential of yet improved future missions such as PLATO 2.0 in detecting solar system analogues. We use real-world solar data and end-to-end simulations to explore the stellar and instrumental noise properties. By injecting and retrieving planets, rings and moons of our own solar system, we show that the discovery of Venus- and Earth-analogues transiting G-dwarfs like our Sun is feasible at high S/N after collecting 6yrs of data, but Mars and Mercury will be difficult to detect due to stellar noise. In the best cases, Saturn's rings and Jupiter's moons will be detectable even in single transit observations. Through the high number (>1bn) of observed stars by PLATO 2.0, it will become possible to detect thousands of single-transit events by cold gas giants, analogue to our Jupiter, Saturn, Uranus and Neptune. Our own solar system aside, we also show, through signal injection a...

  8. Photon-counting soft x-ray telescope for the Solar-C mission

    NASA Astrophysics Data System (ADS)

    Sakao, Taro; Narukage, Noriyuki; Shimojo, Masumi; Tsuneta, Saku; Suematsu, Yoshinori; Miyazaki, Satoshi; Imada, Shinsuke; Nishizuka, Naoto; Watanabe, Kyoko; Dotani, Tadayasu; DeLuca, Edward E.; Ishikawa, Shin-nosuke

    2011-10-01

    We report instrument outline as well as science of the photon-counting soft X-ray telescope that we have been studying as a possible scientific payload for the Japanese Solar-C mission whose projected launch around 2019. Soft X-rays (~1- 10 keV) from the solar corona include rich information on (1) possible mechanism(s) for heating the bright core of active regions seen in soft X-rays (namely, the hottest portion in the non-flaring corona), (2) dynamics and magnetohydrodynamic structures associated with magnetic reconnection processes ongoing in flares, and even (3) generation of supra-thermal distributions of coronal plasmas associated with flares. Nevertheless, imaging-spectroscopic investigation of the soft X-ray corona has so far remained unexplored due to difficulty in the instrumentation for achieving this aim. With the advent of recent remarkable progress in CMOS-APS detector technology, the photon-counting X-ray telescope will be capable of, in addition to conventional photon-integration type exposures, performing imaging-spectroscopic investigation on active regions and flares, thus providing, for example, detailed temperature information (beyond the sofar- utilized filter-ratio temperature) at each spatial point of the observing target. The photon-counting X-ray telescope will emply a Wolter type I optics with a piece of a segmented mirror whose focal length 4 meters, combined with a focal-plane CMOS-APS detector (0.4-0.5"/pixel) whose frame read-out rate required to be as high as 1000 fps.

  9. Search for sub-eV mass solar axions by the CERN Axion Solar Telescope with 3He buffer gas.

    PubMed

    Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Ezer, C; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Gazis, E N; Geralis, T; Giomataris, I; Gninenko, S; Gómez, H; Gruber, E; Guthörl, T; Hartmann, R; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakov?i?, K; Karuza, M; Königsmann, K; Kotthaus, R; Kr?mar, M; Kuster, M; Laki?, B; Laurent, J M; Liolios, A; Ljubi?i?, A; Lozza, V; Lutz, G; Luzón, G; Morales, J; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Rashba, T; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J A; Vogel, J K; Yildiz, S C; Zioutas, K

    2011-12-23

    The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV?m(a)?0.64 eV. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g(a?)?2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)?1.15 eV, comfortably overlapping with cosmological hot dark matter bounds. PMID:22243149

  10. MAST - A mass spectrometer telescope for studies of the isotopic composition of solar, anomalous, and galactic cosmic ray nuclei

    NASA Technical Reports Server (NTRS)

    Cook, Walter R.; Cummings, Alan C.; Cummings, Jay R.; Garrard, Thomas L.; Kecman, Branislav; Mewaldt, Richard A.; Selesnick, Richard S.; Stone, Edward C.; Von Rosenvinge, T. T.

    1993-01-01

    The Mass Spectrometer Telescope (MAST) on SAMPEX is designed to provide high resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z = 2 to 28) over the energy range from about 10 to several hundred MeV/nuc. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona, while during solar quiet times MAST will study the isotopic composition of galactic cosmic rays. In addition, MAST will measure the isotopic composition of both interplanetary and trapped fluxes of anomalous cosmic rays, believed to be a sample of the nearby interstellar medium.

  11. Distributed synthetic apertures for digital holographic imaging

    Microsoft Academic Search

    Yue Gao; Da-Yong Wang; Hua-Kun Cui; Zhi-Wei Zhou; Yun-Xin Wang

    2011-01-01

    A key problem for the digital holography is to improve the resolution of digital holographic system. We present a system for long-range digital holographic imaging with improved resolution using synthetic aperture method. Imaging system is formed by three sub-apertures, and each sub-aperture receiver contains independently telescope lenses and a CCD device. Through every sub-aperture system, a hologram is obtained. Subsequently,

  12. Progress making the top end optical assembly (TEOA) for the 4-meter Advanced Technology Solar Telescope

    NASA Astrophysics Data System (ADS)

    Canzian, Blaise; Barentine, J.; Arendt, J.; Bader, S.; Danyo, G.; Heller, C.

    2012-09-01

    L-3 Integrated Optical Systems (IOS) Division has been selected by the National Solar Observatory (NSO) to design and produce the Top End Optical Assembly (TEOA) for the 4-meter Advanced Technology Solar Telescope (ATST) to operate at Haleakal', Maui. ATST will perform to a very high optical performance level in a difficult thermal environment. The TEOA, containing the 0.65-meter silicon carbide secondary mirror and support, mirror thermal management system, mirror positioning and fast tip-tilt system, field stop with thermally managed heat dump, thermally managed Lyot stop, safety interlock and control system, and support frame, operates in the "hot spot" at the prime focus of the ATST and so presents special challenges. In this paper, we describe progress in the L-3 technical approach to meeting these challenges, including silicon carbide off-axis mirror design, fabrication, and high accuracy figuring and polishing all within L-3; mirror support design; the design for stray light control; subsystems for opto-mechanical positioning and high accuracy absolute mirror orientation sensing; Lyot stop design; and thermal management of all design elements to remain close to ambient temperature despite the imposed solar irradiance load.

  13. Feasibility study of a layer-oriented wavefront sensor for solar telescopes: comment.

    PubMed

    Kellerer, Aglaé

    2014-11-10

    The future generation of telescopes will be equipped with multi-conjugate adaptive-optics (MCAO) systems in order to obtain high angular resolution over large fields of view. MCAO comes in two flavors: star- and layer-oriented. Existing solar MCAO systems rely exclusively on the star-oriented approach. Earlier we suggested a method to implement the layer-oriented approach, and in view of recent concerns by Marino and Wöger [Appl. Opt.53, 685 (2014)10.1364/AO.53.000685APOPAI1559-128X], we now explain the proposed scheme in further detail. We note that in any layer-oriented system one sensor is conjugated to the pupil and the others are conjugated to higher altitudes. For the latter, not all the sensing surface is illuminated by the entire field of view. The successful implementation of nighttime layer-oriented systems shows that the field reduction is no crucial limitation. In the solar approach the field reduction is directly noticeable because it causes vignetting of the Shack-Hartmann subaperture images. It can be accounted for by a suitable adjustment of the algorithms to calculate the local wavefront slopes. We discuss a further concern related to the optical layout of a layer-oriented solar system. PMID:25402984

  14. Fine-scale structures and material flows of quiescent filaments observed by New Vacuum Solar Telescope

    E-print Network

    Yan, X L; Xiang, Y Y; Yang, L H

    2015-01-01

    Study on the small-scale structures and material flows of solar quiescent filaments is very important for understanding the formation and equilibrium of solar filaments. Using the high resolution H{\\alpha} data observed by the New Vacuum Solar Telescope (NVST), we present the structures of the barbs and the material flows along the threads across the spine in two quiescent filaments on 2013 September 29 and on 2012 November 2, respectively. During the evolution of the filament barb, several parallel tube-shaped structures formed and the width of the structures ranges from about 2.3 Mm to 3.3 Mm. The parallel tube-shaped structures merged together accompanied with the material flows from the spine to the barb. Moreover, the boundary between the barb and surrounding atmosphere is very neat. The counter-streaming flows were not found to appear alternately in the adjacent threads of the filament. However, the large-scale patchy counter-streaming flows are detected in the filament. The flows in one patch of the fi...

  15. Current and Planned Solar Wind Observations Using the EISCAT and LOFAR Radio-Telescope Systems

    NASA Astrophysics Data System (ADS)

    Bisi, M. M.; Fallows, R. A.; Jensen, E. A.; Breen, A.; Xiong, M.; Jackson, B. V.

    2011-12-01

    Remote-sensing observations of the inner heliosphere using the technique of interplanetary scintillation (IPS) provide essential information on the velocity and density of developing solar wind structure. For many years, observations of IPS have been undertaken with the European Incoherent SCATter (EISCAT) radio telescopes based across Northern Scandinavia. We are presently developing the IPS experiment for use on new and upcoming cutting-edge instrumentation. Such instrumentation includes the LOw Frequency ARray (LOFAR) which is situated primarily in the Netherlands with additional stations currently sited across central Europe. Using data sets from various IPS-capable systems, the University of California, San Diego (UCSD) three-dimensional (3-D) tomographic-reconstruction and visualisation algorithms can yield reconstruction results for comparison with multi-point it{in-situ} measurements from spacecraft. This makes it possible to study the structure of the inner heliosphere as a whole, including the isolation of individual features or events such as interplanetary coronal mass ejections (ICMEs), stream interaction regions (SIRs), or their interactions with the ambient solar wind as well as the ambient wind itself. We are also testing the Faraday rotation (FR) response at low frequencies using LOFAR. Combined, these techniques have large implications and capabilities for space-weather forecasting. This work is focused on the global structure of the inner heliosphere during the minimum and rise phases of the current solar cycle.

  16. Eyes on the Sun: Solar Instrumentation

    NASA Astrophysics Data System (ADS)

    Uitenbroek, H.

    2013-01-01

    Solar Physics is at the threshold of a new era of high spatial resolution observations with a number of large aperture facilities coming on-line. These facilities will allow us to come closer to resolving phenomena that result from the interaction of plasma with magnetic fields at their natural spatial and temporal scales, an opportunity that is unique in astrophysics. In this paper I review what makes solar telescopes, special, what a typical solar telescope looks like, and how future facilities will be constructed. The design and development of the Utrecht built Dutch Open Telescope (DOT) has contributed significantly to the new directions that the designs of these new facilities have taken.

  17. Co-Alignment System (CAS) study. Report on task 1-3. [Solar Extreme Ultraviolet Telescope and Spectrometer pointing system

    NASA Technical Reports Server (NTRS)

    Anderson, N. T.

    1980-01-01

    The design of a suitable coalignment system (CAS) for the Solar Extreme Ultraviolet Telescope and Spectrometer (SEUTS) is presented. The CAS provides offset adjustment capabilities to SEUTS which will be mounted on a single large pointing system with other devices. The suitability of existing designs is determined and modifications are suggested.

  18. TURBULENT CHARACTERISTICS IN THE INTENSITY FLUCTUATIONS OF A SOLAR QUIESCENT PROMINENCE OBSERVED BY THE HINODE SOLAR OPTICAL TELESCOPE

    SciTech Connect

    Leonardis, E.; Chapman, S. C.; Foullon, C. [Centre for Fusion Space and Astrophysics, Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom)

    2012-02-01

    We focus on Hinode Solar Optical Telescope (SOT) calcium II H-line observations of a solar quiescent prominence (QP) that exhibits highly variable dynamics suggestive of turbulence. These images capture a sufficient range of scales spatially ({approx}0.1-100 arcsec) and temporally ({approx}16.8 s-4.5 hr) to allow the application of statistical methods used to quantify finite range fluid turbulence. We present the first such application of these techniques to the spatial intensity field of a long-lived solar prominence. Fully evolved inertial range turbulence in an infinite medium exhibits multifractal scale invariance in the statistics of its fluctuations, seen as power-law power spectra and as scaling of the higher order moments (structure functions) of fluctuations which have non-Gaussian statistics; fluctuations {delta}I(r, L) = I(r + L) - I(r) on length scale L along a given direction in observed spatial field I have moments that scale as ({delta}I(r, L){sup p}) {approx} L{sup {zeta}(p)}. For turbulence in a system that is of finite size, or that is not fully developed, one anticipates a generalized scale invariance or extended self-similarity (ESS) ({delta}I(r, L){sup p}) {approx} G(L){sup {zeta}(p)}. For these QP intensity measurements we find scaling in the power spectra and ESS. We find that the fluctuation statistics are non-Gaussian and we use ESS to obtain ratios of the scaling exponents {zeta}(p): these are consistent with a multifractal field and show distinct values for directions longitudinal and transverse to the bulk (driving) flow. Thus, the intensity fluctuations of the QP exhibit statistical properties consistent with an underlying turbulent flow.

  19. Long Expositions and Azimuth Aperture Synthesis of Radio Emission Sources at the Radio Telescope RATAN-600 when the Feed Moves Along the Circle Railways

    NASA Astrophysics Data System (ADS)

    Kajdanovskij, N. L.

    Expressions are presented determining an automatic setting of the RATAN-600 reflector profile at the source tracking. A scheme of four-gauge circular railway is described, providing many hours of exposition and an azimuth aperture synthesis of sources. The possible boundaries of zenith distances and azimuths, and also the exposition times for sources with declinations in the limits of ±40°, are determined.

  20. Hubble Space telescope thermal cycle test report for large solar array samples with BSFR cells (Sample numbers 703 and 704)

    NASA Technical Reports Server (NTRS)

    Alexander, D. W.

    1992-01-01

    The Hubble space telescope (HST) solar array was designed to meet specific output power requirements after 2 years in low-Earth orbit, and to remain operational for 5 years. The array, therefore, had to withstand 30,000 thermal cycles between approximately +100 and -100 C. The ability of the array to meet this requirement was evaluated by thermal cycle testing, in vacuum, two 128-cell solar cell modules that exactly duplicated the flight HST solar array design. Also, the ability of the flight array to survive an emergency deployment during the dark (cold) portion of an orbit was evaluated by performing a cold-roll test using one module.

  1. PROPERTIES OF UMBRAL DOTS AS MEASURED FROM THE NEW SOLAR TELESCOPE DATA AND MHD SIMULATIONS

    SciTech Connect

    Kilcik, A.; Yurchyshyn, V. B.; Abramenko, V.; Goode, P. R.; Cao, W. [Big Bear Solar Observatory, Big Bear City, CA 92314 (United States); Rempel, M. [High Altitude Observatory, NCAR, Boulder, CO 80307-3000 (United States); Kitai, R.; Watanabe, H. [Kwasan and Hida Observatories, Kyoto University, Kyoto 607-8417 (Japan)

    2012-02-01

    We studied bright umbral dots (UDs) detected in a moderate size sunspot and compared their statistical properties to recent MHD models. The study is based on high-resolution data recorded by the New Solar Telescope at the Big Bear Solar Observatory and three-dimensional (3D) MHD simulations of sunspots. Observed UDs, living longer than 150 s, were detected and tracked in a 46 minute long data set, using an automatic detection code. A total of 1553 (620) UDs were detected in the photospheric (low chromospheric) data. Our main findings are (1) none of the analyzed UDs is precisely circular, (2) the diameter-intensity relationship only holds in bright umbral areas, and (3) UD velocities are inversely related to their lifetime. While nearly all photospheric UDs can be identified in the low chromospheric images, some small closely spaced UDs appear in the low chromosphere as a single cluster. Slow-moving and long-living UDs seem to exist in both the low chromosphere and photosphere, while fast-moving and short-living UDs are mainly detected in the photospheric images. Comparison to the 3D MHD simulations showed that both types of UDs display, on average, very similar statistical characteristics. However, (1) the average number of observed UDs per unit area is smaller than that of the model UDs, and (2) on average, the diameter of model UDs is slightly larger than that of observed ones.

  2. Radiation concerns for the Solar-A soft x-ray telescope

    NASA Astrophysics Data System (ADS)

    Acton, Loren W.; Morrison, Mons D.; Janesick, James R.; Elliott, Tom S.

    1991-07-01

    The charge-coupled device (CCD) camera of the Soft X-ray Telescope (SXT) for the Japanese Solar-A Mission utilizes a 1024 X 1024 virtual phase CCD manufactured by Texas Instruments in Japan. This sensor will be subject to radiation in the form of trapped protons from the earth's radiation belts and soft x-rays (0.2-4 keV) in the solar image. Proton damage produces 'dark spikes' or pixels of enhanced dark current. This can be characterized in terms of the average increase in dark current as a function of proton fluence and predicted through proton transfer calculations. During the preparation of this camera it has been discovered that exposure to soft x-rays creates 'permanent' ionization damage in the gate insulator, resulting in flat-band shift, dark current increase, loss of charge transfer efficiency, and, ultimately, total unpinning of the sensor. It has been found that ultra-violet, and to a lesser degree, visible-light flooding photo-emits free electrons into the gate oxide which 'anneals' the damage, restoring proper operation of the CCD.

  3. Assembly of a large modular optical telescope (ALMOST)

    E-print Network

    Mohan, Swati

    Future space telescope programs need to assess in-space robotic assembly of large apertures at GEO and ESL2 to support ever increasing aperture sizes. Since such large apertures will not fit within a fairing, they must ...

  4. Dynamics in Sunspot Umbra as Seen in New Solar Telescope and Interface Region Imaging Spectrograph Data

    NASA Astrophysics Data System (ADS)

    Yurchyshyn, V.; Abramenko, V.; Kilcik, A.

    2015-01-01

    We analyze sunspot oscillations using Interface Region Imaging Spectrograph (IRIS) slit-jaw and spectral data and narrow-band chromospheric images from the New Solar Telescope (NST) for the main sunspot in NOAA AR 11836. We report that the difference between the shock arrival times as measured by the Mg II k 2796.35 Ĺ and Si IV 1393.76 Ĺ line formation levels changes during the observed period, and peak-to-peak delays may range from 40 s to zero. The intensity of chromospheric shocks also displays long-term (about 20 min) variations. NST's high spatial resolution H? data allowed us to conclude that, in this sunspot, umbral flashes (UFs) appeared in the form of narrow bright lanes stretched along the light bridges and around clusters of umbral bright points. The time series also suggested that UFs preferred to appear on the sunspot-center side of light bridges, which may indicate the existence of a compact sub-photospheric driver of sunspot oscillations. The sunspot's umbra as seen in the IRIS chromospheric and transition region data appears bright above the locations of light bridges and the areas where the dark umbra is dotted with clusters of umbral dots. Co-spatial and co-temporal data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory showed that the same locations were associated with bright footpoints of coronal loops suggesting that the light bridges may play an important role in heating the coronal sunspot loops. Finally, the power spectra analysis showed that the intensity of chromospheric and transition region oscillations significantly vary across the umbra and with height, suggesting that umbral non-uniformities and the structure of sunspot magnetic fields may play a role in wave propagation and heating of umbral loops.

  5. A Method for Measuring the Image Distortion in the GONG Solar Telescopes II

    NASA Astrophysics Data System (ADS)

    Sudol, J. J.; Harvey, J. W.; Toner, C. G.

    2002-12-01

    Knowledge of the distortion in an image is important in a number of applications. This is especially true in helioseismology where errors in either time or position degrade inferences about internal solar structure and dynamics. Previously (BAAS 34(2), 732, 2002), we proposed a method for measuring the distortion in the images obtained with the Global Oscillation Network Group solar telescopes. After running a number of simulations, we have made some critical modifications to our method. Our attempts to solve simultaneously for the image center and the distortion have proven to be unstable. We now solve first for the image center and then for the distortion. Methods that involve a large number of free parameters are imprecise because the solution space tends to be shallow and littered with local minima. The large number of calibration images and image points required to improve on this situation is impractical. In an effort to reduce the number of free parameters in our method, our error metric is now based on the differences in the distances between pairs of image points across all of the calibration images obtained. In addition to these modifications, we now register the calibration images before and after correcting the images for distortion. The scatter in the image point positions in the first case sets an upper limit on the distortion and in the second case sets an upper limit on the extent to which corrections for the distortion can be made. In simulations, we have been able to correct for distortion to 0.1 pixel, an order of magnitude above our desired correction of 0.01 pixel, which is comparable to the error in determining the positions of the image points.

  6. Progress Report of the new Solar Sub-Millimeter Telescope Installation

    NASA Astrophysics Data System (ADS)

    Kaufmann, P.; Magun, A.; Levato, H.; Rovira, M.; Arzner, K.; Correia, E.; Costa, J. E. R.; Gimenez de Castro, C. G.; Kaempfer, N.; Raulin, J. P.; Rolli, E.; Silva, A. V. R.

    1998-11-01

    The Sub-Millimeter Solar Telescope (SST) project is now in his final phase of construction and a definitive schedule has been established. The 1.5 m diameter reflector has been completed by Steward Observatory, University of Arizona, presenting an excellent surface with a deviation of 18 microns (r.m.s.). The delay of the reflector construction was the result of the new technology employed, and mainly due to the slumping of the reflector which needed additional technological research (Kingsley et al. 1998). The SST building, including one 3.4 m ESSCO gore-tex radom and a room for two complementary optical imaging spectrographs (from IAP, Bern and OV, UFRJ, Brazil), has been completed now by CASLEO at El Leoncito, San Juan, Argentina. Numerous electrical, electronical, mechanical tests, as well as softwares tests, have been performed at the IAP, Bern, Switzerland, and at Itapetinga, Brazil. The 1.5 m reflector is in Bern, already assembled to the other SST parts: four 210 and two 405 GHZ radiometers built by RPG, the ORBIT positionner, the interface box between the reflector and the radiometers, the counter-weights. Test and integration of the SST are being done at Bern, with a co-participation of researchers and technicians of CRAAE and CASLEO. The shipment of the SST to El Leoncito will be mid-October, and the final installation is scheduled for the period January-April of 1999. The first tests and solar observations are planned for May of 1999. The SST project received main financial support from FAPESP (Proc. 93/3321-7), complemented by funds from the IAP, Switzerland, and, IAFE and CASLEO/CONICET, Argentina.

  7. Precursor of Sunspot Penumbral Formation Discovered with Hinode Solar Optical Telescope Observations

    NASA Astrophysics Data System (ADS)

    Shimizu, Toshifumi; Ichimoto, Kiyoshi; Suematsu, Yoshinori

    2012-03-01

    We present observations of a precursory signature that would be helpful for understanding the formation process of sunspot penumbrae. The Hinode Solar Optical Telescope successfully captured the entire evolution of a sunspot from the pore to a large well-developed sunspot with penumbra in an emerging flux region appearing in NOAA Active Region 11039. We found an annular zone (width 3''-5'') surrounding the umbra (pore) in Ca II H images before the penumbra formed around the umbra. The penumbra developed as if to fill the annular zone. The annular zone shows weak magnetogram signals, meaning less magnetic flux or highly inclined fields there. Pre-existing ambient magnetic field islands were distributed at the outer edge of the annular zone and did not come into the zone. There are no strong systematic flow patterns in the zone, but we occasionally observed small magnetic flux patches streaming out. The observations indicate that the annular zone is different from the sunspot moat flow region and that it represents the structure in the chromosphere. We conclude that the annular zone reflects the formation of a magnetic canopy overlying the region surrounding the umbra at the chromospheric level, long before the formation of the penumbra at the photospheric level. The magnetic field structure in the chromosphere needs to be considered in the formation process of the penumbrae.

  8. PRECURSOR OF SUNSPOT PENUMBRAL FORMATION DISCOVERED WITH HINODE SOLAR OPTICAL TELESCOPE OBSERVATIONS

    SciTech Connect

    Shimizu, Toshifumi [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan); Ichimoto, Kiyoshi [Kwasan and Hida Observatories, Kyoto University, Kamitakara-cho, Takayama, Gifu 506-1314 (Japan); Suematsu, Yoshinori, E-mail: shimizu.toshifumi@isas.jaxa.jp [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

    2012-03-10

    We present observations of a precursory signature that would be helpful for understanding the formation process of sunspot penumbrae. The Hinode Solar Optical Telescope successfully captured the entire evolution of a sunspot from the pore to a large well-developed sunspot with penumbra in an emerging flux region appearing in NOAA Active Region 11039. We found an annular zone (width 3''-5'') surrounding the umbra (pore) in Ca II H images before the penumbra formed around the umbra. The penumbra developed as if to fill the annular zone. The annular zone shows weak magnetogram signals, meaning less magnetic flux or highly inclined fields there. Pre-existing ambient magnetic field islands were distributed at the outer edge of the annular zone and did not come into the zone. There are no strong systematic flow patterns in the zone, but we occasionally observed small magnetic flux patches streaming out. The observations indicate that the annular zone is different from the sunspot moat flow region and that it represents the structure in the chromosphere. We conclude that the annular zone reflects the formation of a magnetic canopy overlying the region surrounding the umbra at the chromospheric level, long before the formation of the penumbra at the photospheric level. The magnetic field structure in the chromosphere needs to be considered in the formation process of the penumbrae.

  9. Plate coil thermal test bench for the Daniel K. Inouye Solar Telescope (DKIST) carousel cooling system

    NASA Astrophysics Data System (ADS)

    Phelps, LeEllen; Murga, Gaizka; Montijo, Guillermo; Hauth, David

    2014-08-01

    Analyses have shown that even a white-painted enclosure requires active exterior skin-cooling systems to mitigate dome seeing which is driven by thermal nonuniformities that change the refractive index of the air. For the Daniel K. Inouye Solar Telescope (DKIST) Enclosure, this active surface temperature control will take the form of a system of water cooled plate coils integrated into the enclosure cladding system. The main objective of this system is to maintain the surface temperature of the enclosure as close as possible to, but always below, local ambient temperature in order to mitigate this effect. The results of analyses using a multi-layer cladding temperature model were applied to predict the behavior of the plate coil cladding system and ultimately, with safety margins incorporated into the resulting design thermal loads, the detailed designs. Construction drawings and specifications have been produced. Based on these designs and prior to procurement of the system components, a test system was constructed in order to measure actual system behavior. The data collected during seasonal test runs at the DKIST construction site on Haleakal? are used to validate and/or refine the design models and construction documents as appropriate. The test fixture was also used to compare competing hardware, software, components, control strategies, and configurations. This paper outlines the design, construction, test protocols, and results obtained of the plate coil thermal test bench for the DKIST carousel cooling system.

  10. Progress Report of the New Solar Submm-Wave Telescope (SST) Installation

    NASA Astrophysics Data System (ADS)

    Kaufman, P.; Magun, A.; Levato, H.; Rovira, M.; Arzner, K.; Correia, E.; Costa, J. E. R.; Giménez de Castro, C. G.; Kämpfer, N.; Raulin, J.-P.; Rolli, E.; Silva, A. V. R.

    1999-12-01

    The Solar Sub-Millimeter wave Telescope (SST) is now in its final stage of construction and a definite schedule has been established. The 1.5 m diameter reflector has been completed and presents an excellent surface with a deviation of 18 microns (r.m.s.). The reflector construction employed the new "slumping" technique (Martin et al. 1998). The SST building, including one 3.4 m gore-tex radome and a room for optical imaging spectrographs (from IAP, Bern and OV, UFRJ, Brasil), has been completed now at El Leoncito, San Juan, Argentina. Numerous electrical, electronical, mechanical tests, as well as software tests, have been performed at the IAP, Bern, Switzerland, and at Itapetinga, Brasil. The SST was assembled in Bern, consisting of the 1.5 m reflector, four 210 and two 405 GHz radiometers, the positioner, the interface box between the reflector and the radiometers, and the counter-weights. Part of the tests and integration of the SST is beeing done at Bern, with a co-participation of researchers and technicians of CRAAE and CASLEO. The shipment of the SST to El Leoncito will be in February 1999, and the final installation is scheduled for the period March-May 1999. The SST project received main financial support from the Brazilian Agency FAPESP (Proc. 93/3321-7), complemented by funds from the IAFE and CASLEO/CONICET, Argentina, and the IAP, Switzerland.

  11. The Planet Pipeline: Enabling Data Mining and Citizen Science with Hubble Space Telescope Solar System Images

    NASA Astrophysics Data System (ADS)

    Deustua, S.; Mutchler, M.; Conti, A.; Viana, A.; Wong, M. H.; Gay, P.

    2012-12-01

    In 15 years of service, the Wide Field Planetary Camera 2 (WFPC2) onboard the Hubble Space Telescope (HST) obtained over 10,000 frames of Solar System data. Since HST's standard data reduction pipelines are not optimized for moving target data, our "planet pipeline" will uniformly reprocess and catalog this WFPC2 image collection to make it more immediately science-ready. Some of our processing steps will utilize citizen scientists to perform visual inspections. Our "Planet Investigators" website, built on CosmoQuest infrastructure, will allow people to assist us in verifying our artifact rejections and assemble object catalogs. It is now easily possible to have each image inspected multiple times, and set up iterative processes that can converge on the optimal output with greater confidence. Our corresponding database will enable robust queries which are more specific to planetary science, helping archival researchers quickly find and utilize the prepared images within our collection for a wide range of scientific analyses. Our processed images and associated catalogs will be made available as High Level Science Products (HLSP) in the Multimission Archive at STScI (MAST): http://archive.stsci.edu/prepds/planetpipeline

  12. Witnessing magnetic twist with high-resolution observation from the 1.6-m New Solar Telescope

    NASA Astrophysics Data System (ADS)

    Wang, Haimin; Cao, Wenda; Liu, Chang; Xu, Yan; Liu, Rui; Zeng, Zhicheng; Chae, Jongchul; Ji, Haisheng

    2015-04-01

    Magnetic flux ropes are highly twisted, current-carrying magnetic fields. They are crucial for the instability of plasma involved in solar eruptions, which may lead to adverse space weather effects. Here we present observations of a flaring using the highest resolution chromospheric images from the 1.6-m New Solar Telescope at Big Bear Solar Observatory, supplemented by a magnetic field extrapolation model. A set of loops initially appear to peel off from an overall inverse S-shaped flux bundle, and then develop into a multi-stranded twisted flux rope, producing a two-ribbon flare. We show evidence that the flux rope is embedded in sheared arcades and becomes unstable following the enhancement of its twists. The subsequent motion of the flux rope is confined due to the strong strapping effect of the overlying field. These results provide a first opportunity to witness the detailed structure and evolution of flux ropes in the low solar atmosphere.

  13. Impacts on Hubble Space Telescope solar arrays: discrimination between natural and man-made particles.

    NASA Astrophysics Data System (ADS)

    Kearsley, A. T.; Drolshagen, G.; McDonnell, J. A. M.; Mandeville, J.-C.; Moussi, A.

    A Post-Flight Investigation was initiated by the European Space Agency to analyze impact fluxes on solar arrays of the Hubble Space Telescope (HST), exposed to space for 8.25 years at approximately 600 km altitude. The solar cells were deployed during servicing mission SM-1 (December 1993), and retrieved by shuttle orbiter Columbia in March 2002 (SM-3B). A sub-panel of 2 m2 was cut from the --V2 wing and cells were selected for in-depth analysis. Twelve cells (9.6x10-3 m2) were surveyed for flux of all craters of sizes greater than 5 microns Dco; six at the NHM, and six at ONERA. Cumulative flux plots reveal slightly greater abundance of very small craters than in a comparable survey of SM-1 cells. Analytical scanning electron microscopy was used to locate impact features and to analyse residues at the NHM. 103 features of 3 -- 4000 micron conchoidal detachment diameter (Dco) were located on a total of 17 solar cells. 78 features show identifiable residue: 36 are Space Debris impacts and 42 Micrometeoroid impacts. Of the remaining 25: 4 contain residue of ambiguous origin, 1 is a minor manufacturing flaw, 1 is obscured by contamination, and 19 are unresolved, lacking recognizable residue. Space debris impacts on the SM-3B cells are all less than 80 microns Dco, dominated by Al- rich residue, probably of solid rocket motor origin, some may be unburnt fuel. Three craters may be sodium metal droplet impacts. No residues from paint pigment, aluminium or ferrous alloys, or copper- and tin-bearing metal were found. All craters larger than 100 microns are of micrometeoroid origin, or unresolved. Most residues are magnesium-iron silicate or iron sulfide. A few craters show vesicular Mg, S, Fe and Ni residue. A single Fe Ni metal residue was found, as well as enigmatic Mg- and S-bearing residues, all considered of micrometeoroid origin. A few Fe-, O- and C-bearing residues were classified as of ambiguous origin. The quality and quantity of residue is clearly linked to the crater pit morphology, with oval pit features containing more identifiable residue, perhaps due to lower peak shock pressures experienced in these oblique-incidence impacts.

  14. Multi-Aperture 3D Imaging Systems

    Microsoft Academic Search

    Joseph C. Marron; R. L. Kendrick

    2008-01-01

    With a multi-aperture imaging system, one creates a large imaging aperture by combining the light from a series of distributed telescopes. In doing this, one can construct a fine-resolution imaging system with reduced volume. We present work on multi-aperture, active imaging systems that use coherent detection and digital image formation. In such a system, the image formation process incorporates digital

  15. Production of the 4.26 m ZERODUR mirror blank for the Advanced Technology Solar telescope (ATST)

    NASA Astrophysics Data System (ADS)

    Jedamzik, Ralf; Werner, Thomas; Westerhoff, Thomas

    2014-07-01

    The Daniel K. Inouye Solar Telescope (DKIST, formerly the Advanced Technology Solar Telescope, ATST) will be the most powerful solar telescope in the world. It is currently being built by the Association of Universities for Research in Astronomy (AURA) in a height of 3000 m above sea level on the mountain Haleakala of Maui, Hawaii. The primary mirror blank of diameter 4.26 m is made of the extremely low thermal expansion glass ceramic ZERODUR® of SCHOTT AG Advanced Optics. The DKIST primary mirror design is extremely challenging. With a mirror thickness of only 78 to 85 mm it is the smallest thickness ever machined on a mirror of 4.26 m in diameter. Additionally the glassy ZERODUR® casting is one of the largest in size ever produced for a 4 m class ZERODUR® mirror blank. The off axis aspherical mirror surface required sophisticated grinding procedures to achieve the specified geometrical tolerance. The small thickness of about 80 mm required special measures during processing, lifting and transport. Additionally acid etch treatment was applied to the convex back-surface and the conical shaped outer diameter surface to improve the strength of the blank. This paper reports on the challenging tasks and the achievements on the material property and dimensional specification parameter during the production of the 4.26 m ZERODUR® primary mirror blank for AURA.

  16. a Re-Evaluation of the Neutron Emission from the Solar Flare of September 07, 2005, Detected by the Solar Neutron Telescope at Sierra Negra.

    NASA Astrophysics Data System (ADS)

    González, Xavier

    The X17.0 solar flare of September 7, 2005 released high-energy neutrons, which were detected by the Solar Neutron Telescope (SNT) at Sierra Negra, Mexico. In three separate and independent studies of this solar neutron event, the energy spectra was calculated as a power law. In this paper, we present an alternative analysis, based on improved numerical simulations of the detector using GEANT4, and a different technique to process the SNT data. The results indicate that the spectral index which best fits the neutron flux is around 3, in agreement with previous works. Based on the numerically calculated neutron energy deposition on the SNT, we confirm that the neutrons detected had at least 1 GeV, this implies that the parent solar flare most probably produced 10 GeV protons; these could not be observed at Earth, as theit was an east limb event.

  17. High resolution telescope

    DOEpatents

    Massie, Norbert A. (San Ramon, CA); Oster, Yale (Danville, CA)

    1992-01-01

    A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employs speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by an electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activites. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.

  18. Small-Scale Magnetic-Flux Emergence Observed with Hinode Solar Optical Telescope

    NASA Astrophysics Data System (ADS)

    Otsuji, Kenichi; Shibata, Kazunari; Kitai, Reizaburo; Ueno, Satoru; Nagata, Shin'ichi; Matsumoto, Takuma; Nakamura, Tahei; Watanabe, Hiroko; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D.; Lites, Bruce; Shine, Richard A.; Title Alan M.

    2007-11-01

    We observed small-scale magnetic-flux emergence in a sunspot moat region by the Solar Optical Telescope (SOT) aboard the Hinode satellite. We analyzed filtergram images observed at wavelengths of Fe 6302Ĺ, G band, and CaII H. In Stokes I images of Fe 6302Ĺ, emerging magnetic flux was recognized as dark lanes. In the G band, they showed to be their shapes almost the same as in Stokes I images. These magnetic fluxes appeared as dark filaments in CaII H images. Stokes V images of Fe 6302Ĺ showed pairs of opposite polarities at footpoints of each filament. These magnetic concentrations were identified to correspond to bright points in G band/CaII H images. From an analysis of time-sliced diagrams, we derived the following properties of emerging flux, which are consistent with those of previous studies: (1) Two footpoints separate each other at a speed of 4.2kms-1 during the initial phase of evolution, and decrease to about 1kms-1 10minutes later. (2) CaII H filaments appear almost simultaneously with the formation of dark lanes in Stokes I in an observational cadence of 2minutes. (3) The lifetime of the dark lanes in the Stokes I and G band is 8minutes, while that of Ca filament is 12minutes. An interesting phenomena was observed, that an emerging flux tube expanded laterally in the photosphere with a speed of 3.8kms-1. A discussion on the horizontal expansion of the flux tube is given with refernce to previous simulation studies.

  19. Space telescope

    NASA Astrophysics Data System (ADS)

    Bulkin, B. R.

    1985-02-01

    The NASA 2.4-m aperture Space Telescope (ST) will be associated with the Space Shuttle, the Tracking and Data Relay System, the Communications Center at White Sands, the Space Telescope Operations Control Center at Goddard, and the Science Institute at Johns Hopkins University. Attention is presently given to the features of the Scientific Instruments and Optical Telescope Assembly, which encompasses the Wide Field/Planetary Camera, the Faint Object Camera, the Faint Object Spectrograph, the High Resolution Spectrograph, the High Speed Photometer, and the Fine Guidance System. The ST Support System Module and Subsystems is composed of the Thermal Control System, the Electrical Power System, the Pointing Control Subsystem, and the Onboard Instrumentation and Communication Subsystem.

  20. A normal incidence, high resolution X-ray telescope for solar coronal observations

    NASA Technical Reports Server (NTRS)

    Golub, L.

    1984-01-01

    A Normal Incidence high resolution X-ray Telescope is reported. The design of a telescope assembly which, after fabrication, will be integrated with the mirror fabrication process is described. The assembly is engineered to fit into the Black Brant rocket skin to survive sounding rocket launch conditions. A flight ready camera is modified and tested.

  1. LSST Telescope Design Developments

    Microsoft Academic Search

    V. L. Krabbendam; J. H. Burge; C. F. Claver; B. Cuerden; W. Davison; W. J. Gressler; J. Kingsley; H. M. Martin; D. R. Neill; S. Olivier; D. Phillion; J. Sebag; D. Sweeney

    2005-01-01

    The proposed Large Synoptic Survey Telescope (LSST) has an 8.4 meter aperture with a 3.5 degree diameter field of view and must meet the challenging cadence requirements necessary to perform the LSST survey mission. Several advances have been made in the concept design of the telescope. The telescope optical system is based on a Paul-Baker three element design with a

  2. Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.

    PubMed

    Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Da Riva, E; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Garza, J G; Gazis, E N; Geralis, T; Georgiopoulou, E; Giomataris, I; Gninenko, S; Gómez, H; Gómez Marzoa, M; Gruber, E; Guthörl, T; Hartmann, R; Hauf, S; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakov?i?, K; Karuza, M; Königsmann, K; Kotthaus, R; Kr?mar, M; Kuster, M; Laki?, B; Lang, P M; Laurent, J M; Liolios, A; Ljubi?i?, A; Luzón, G; Neff, S; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Shilon, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J; Vogel, J K; Yildiz, S C; Zioutas, K

    2014-03-01

    The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ? ma ? 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of ga? ? 3.3 × 10(-10)? GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of ga?, for example by the currently discussed next generation helioscope International AXion Observatory. PMID:24655238

  3. Performance of the SciBar cosmic ray telescope (SciCRT) toward the detection of high-energy solar neutrons in solar cycle 24

    NASA Astrophysics Data System (ADS)

    Sasai, Yoshinori; Nagai, Yuya; Itow, Yoshitaka; Matsubara, Yutaka; Sako, Takashi; Lopez, Diego; Itow, Tsukasa; Munakata, Kazuoki; Kato, Chihiro; Kozai, Masayoshi; Miyazaki, Takahiro; Shibata, Shoichi; Oshima, Akitoshi; Kojima, Hiroshi; Tsuchiya, Harufumi; Watanabe, Kyoko; Koi, Tatsumi; Valdés-Galicia, Jose Francisco; González, Luis Xavier; Ortiz, Ernesto; Musalem, Octavio; Hurtado, Alejandro; Garcia, Rocio; Anzorena, Marcos

    2014-12-01

    We plan to observe solar neutrons at Mt. Sierra Negra (4,600 m above sea level) in Mexico using the SciBar detector. This project is named the SciBar Cosmic Ray Telescope (SciCRT). The main aims of the SciCRT project are to observe solar neutrons to study the mechanism of ion acceleration on the surface of the sun and to monitor the anisotropy of galactic cosmic-ray muons. The SciBar detector, a fully active tracker, is composed of 14,848 scintillator bars, whose dimension is 300 cm × 2.5 cm × 1.3 cm. The structure of the detector enables us to obtain the particle trajectory and its total deposited energy. This information is useful for the energy reconstruction of primary neutrons and particle identification. The total volume of the detector is 3.0 m × 3.0 m × 1.7 m. Since this volume is much larger than the solar neutron telescope (SNT) in Mexico, the detection efficiency of the SciCRT for neutrons is highly enhanced. We performed the calibration of the SciCRT at Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) located at 2,150 m above sea level in Mexico in 2012. We installed the SciCRT at Mt. Sierra Negra in April 2013 and calibrated this detector in May and August 2013. We started continuous observation in March 2014. In this paper, we report the detector performance as a solar neutron telescope and the current status of the SciCRT.

  4. The James Webb Space Telescope

    NASA Technical Reports Server (NTRS)

    Mather, John

    2003-01-01

    The James Webb Space Telescope (JWST) will extend the discoveries of the Hubble Space Telescope by deploying a large cooled infrared telescope at the Sun-Earth Lagrange point L2. It will have a 6 m aperture and three instruments covering the wavelength range from 0.6 to 28 microns.

  5. Ultra high resolution images of the solar chromosphere and corona using coordinated rocket and balloon observations

    NASA Technical Reports Server (NTRS)

    Walker, Arthur B. C., Jr.; Timothy, J. G.; Hoover, Richard B.; Barbee, Troy W., Jr.

    1993-01-01

    A discussion is presented of the scientific objectives that can be pursued by simultaneous coronal/chromospheric observation with the Multi-Spectral Solar Telescope Array (MSSTA), and a new balloon-borne observatory called the Ultra-High Resolution Vacuum Ultraviolet Spectroheliograph (UHRVS). Attention is given to the proposed UHRVS observatory, which will incorporate two instruments, a 65-cm aperture telescope with narrowband filters for high resolution photographic and photoelectric spectroheliograms, and a very high resolution spectrograph which uses a 40-cm aperture telescope. The capabilities of the MSSTA, and the joint UHRVS/MSSTA observing program that is envisioned are reviewed.

  6. A normal incidence, high resolution X-ray telescope for solar coronal observations

    NASA Technical Reports Server (NTRS)

    Golub, L.

    1984-01-01

    Efforts directed toward the completion of an X-ray telescope assembly design, the procurement of major components, and the coordination of optical fabrication and X-ray multilayer testing are reported.

  7. Thermally Induced Vibrations of the Hubble Space Telescope's Solar Array 3 in a Test Simulated Space Environment

    NASA Technical Reports Server (NTRS)

    Early, Derrick A.; Haile, William B.; Turczyn, Mark T.; Griffin, Thomas J. (Technical Monitor)

    2001-01-01

    NASA Goddard Space Flight Center and the European Space Agency (ESA) conducted a disturbance verification test on a flight Solar Array 3 (SA3) for the Hubble Space Telescope using the ESA Large Space Simulator (LSS) in Noordwijk, the Netherlands. The LSS cyclically illuminated the SA3 to simulate orbital temperature changes in a vacuum environment. Data acquisition systems measured signals from force transducers and accelerometers resulting from thermally induced vibrations of the SAI The LSS with its seismic mass boundary provided an excellent background environment for this test. This paper discusses the analysis performed on the measured transient SA3 responses and provides a summary of the results.

  8. Receive Transmit Telescope Telescope

    E-print Network

    Receive Transmit Telescope Telescope Acquisition, Tracking, and Pointing Technology Development technologies. BRMS utilizes two optically coupled telescopes to relay a laser source from the ground telescope is attached to the spacecraft bus with navigation and attitude control subsystems. The BRMS

  9. Thermal Performance of the Hubble Space Telescope (HST) Solar Array-3 During the Disturbance Verification Test (DVT)

    NASA Technical Reports Server (NTRS)

    Nguyen, Daniel H.; Skladany, Lynn M.; Prats, Benito D.; Griffin, Thomas J. (Technical Monitor)

    2001-01-01

    The Hubble Space Telescope (HST) is one of NASA's most productive astronomical observatories. Launched in 1990, the HST continues to gather scientific data to help scientists around the world discover amazing wonders of the universe. To maintain HST in the fore front of scientific discoveries, NASA has routinely conducted servicing missions to refurbish older equipment as well as to replace existing scientific instruments with better, more powerful instruments. In early 2002, NASA will conduct its fourth servicing mission to the HST. This servicing mission is named Servicing Mission 3B (SM3B). During SM3B, one of the major refurbishment efforts will be to install new rigid-panel solar arrays as a replacement for the existing flexible-foil solar arrays. This is necessary in order to increase electrical power availability for the new scientific instruments. Prior to installing the new solar arrays on HST, the HST project must be certain that the new solar arrays will not cause any performance degradations to the observatory. One of the major concerns is any disturbance that can cause pointing Loss of Lock (LOL) for the telescope. While in orbit, the solar-array temperature transitions quickly from sun to shadow. The resulting thermal expansion and contraction can cause a "mechanical disturbance" which may result in LOL. To better characterize this behavior, a test was conducted at the European Space Research and Technology Centre (ESTEC) in the Large Space Simulator (LSS) thermal-vacuum chamber. In this test, the Sun simulator was used to simulate on-orbit effects on the solar arrays. This paper summarizes the thermal performance of the Solar Array-3 (SA3) during the Disturbance Verification Test (DVT). The test was conducted between 26 October 2000 and 30 October 2000. Included in this paper are: (1) brief description of the SA3's components and its thermal design; (2) a summary of the on-orbit temperature predictions; (3) pretest thermal preparations; (4) a description of the chamber and thermal monitoring sensors; and (6) presentation of test thermal data results versus flight predictions.

  10. Multiple instrument distributed aperture sensor (MIDAS) evolved design concept

    Microsoft Academic Search

    David Stubbs; Alan Duncan; Joseph T. Pitman; Robert Sigler; Rick Kendrick; Eric H. Smith; James Mason

    2004-01-01

    An innovative approach to future space telescopes that enables order of magnitude increased science return for astronomical, Earth-observing and planetary science missions is described. Our concept, called Multiple Instrument Distributed Aperture Sensor (MIDAS), provides a large-aperture, wide-field, diffraction-limited telescope at a fraction of the cost, mass and volume of conventional space telescopes. MIDAS integrates many optical interferometry advances as an

  11. The Advanced Solar Observatory

    NASA Astrophysics Data System (ADS)

    Walker, Arthur B. C., Jr.; Bailey, Wayne; Chupp, Edward L.; Hudson, Hugh S.; Moore, Ronald; Roberts, William; Hoover, Richard B.

    1990-10-01

    A conceptual plan for the development of a comprehensive long duration solar space observatory, The Advanced Solar Observatory (ASO) is described. The ASO is intended to provide solar astronomers with the observational power necessary to address fundamental problems relating to the solar convection zone and activity cycle; the thermal and nonthermal processes that control the transport of energy, mass, and magnetic flux in the solar atmosphere; the generation of the solar wind; and the dynamics of the inner heliosphere. The ASO concept encompasses three proposed Space Station-based instrument ensembles: (1) the High Resolution Telescope Cluster, which includes far ultraviolet, extreme ultraviolet, and X-ray telescopes; (2) the Pinhole/Occulter Facility, which includes Fourier transform and coded aperture hard X-ray and gamma ray telescopes and occulted ultraviolet and visible light coronagraphs; and (3) the High Energy Facility, which contains neutron, gamma ray, and low frequency radio spectrometers. Two other facilities, the Orbiting Solar Laboratory, and a package of Global Dynamics Instrumentation, will, with the Space Station ensembles, form a comprehensive capability for solar physics. The scientific program of the ASO, current instrument concepts for the Space Station based ASO instrument ensembles, and plans for their accommodation on the Space Station are described.

  12. Adaptive membrane for large lightweight space telescopes

    Microsoft Academic Search

    Dimitry Gorinevsky; T. Tupper Hyde

    2002-01-01

    Large, lightweight telescopes in space will enable future earth science, space science, and reconnaissance. The state of the art in space telescope is the Hubble Space Telescope launched in 1990 with its 2.4 m primary mirror. Missions within the decade such as the Next Generation Space Telescope will push this aperture diameter to over 6.5 m. But truly revolutionary observation

  13. NEAT: an astrometric space telescope to search for habitable exoplanets in the solar neighborhood

    NASA Astrophysics Data System (ADS)

    Crouzier, A.; Malbet, F.; Kern, P.; Feautrier, P.; Preiss, O.; Martin, G.; Henault, F.; Stadler, E.; Lafrasse, S.; Behar, E.; Saintpe, M.; Dupont, J.; Potin, S.; Lagage, P.-O.; Cara, C.; Leger, A.; Leduigou, J.-M.; Shao, M.; Goullioud, R.

    2014-03-01

    The last decade has witnessed a spectacular development of exoplanet detection techniques, which led to an exponential number of discoveries and a great diversity of known exoplanets. However, it must be noted that the quest for the holy grail of astrobiology, i.e. a nearby terrestrial exoplanet in habitable zone around a solar type star, is still ongoing and proves to be very hard. Radial velocities will have to overcome stellar noise if there are to discover habitable planets around stars more massive than M ones. For very close systems, transits are impeded by their low geometrical probability. Here we present an alternative concept: space astrometry. NEAT (Nearby Earth Astrometric Telescope) is a concept of astrometric mission proposed to ESA which goal is to make a whole sky survey of close (less then 20 pc) planetary systems. The detection limit required for the instrument is the astrometric signal of an Earth analog (at 10 pc). Differential astrometry is a very interesting tool to detect nearby habitable exoplanets. Indeed, for F, G and K main sequence stars, the astrophysical noise is smaller than the astrometric signal, contrary to the case for radial velocities. The difficulty lies in the fact that the signal of an exo-Earth around a G type star at 10 pc is a tiny 0.3 micro arc sec, which is equivalent to a coin on the moon, seen from the Earth: the main challenge is related to instrumentation. In order to reach this specification, NEAT consists of two formation flying spacecraft at a 40m distance, one carries the mirror and the other one the focal plane. Thus NEAT has a configuration with only one optical surface: an off-axis parabola. Consequently, beamwalk errors are common to the whole field of view and have a small effect on differential astrometry. Moreover a metrology system projects young fringes on the focal plane, which can characterize the pixels whenever necessary during the mission. NEAT has two main scientific objectives: combined with radial velocities and direct imaging, it will explore in a quasi systematic way the nearby planetary systems. The resulting catalog of planetary systems will be very useful to constrain planetary formation models. The second objective is to find very close Earth analogs. These will be top priority targets for a spectroscopic mission aimed at detecting biomarquers. The current activities related to NEAT revolve around 3 themes: i) a lab demonstration: an optical bench replicates the NEAT optical configuration and metrology system in order to demonstrate the feasibility of measuring centroids with a differential accuracy of 5 µpixels (corresponding to 0.3 micro arc sec on sky) ii) a definition phase study of the NEAT mission done by CNES (the "French Space Agency") iii) an end to end simulation of the NEAT data reduction pipeline: from astrometric and RVs measurements to planets All of these activities are focused on the need to answer the next ESA call for M class missions in 2014 with an improved NEAT concept.

  14. Direct imaging of extra-solar planetary systems with the Circumstellar Imaging Telescope (CIT)

    NASA Technical Reports Server (NTRS)

    Terrile, Richard J.

    1988-01-01

    In a joint study conducted by the Jet Propulsion Laboratory and the Perkin-Elmer Corporation it was found that an earth orbital, 1.5 meter diameter low scattered light coronagraphic telescope can achieve a broad range of scientific objectives including the direct detection of Jupiter-sized planets around the nearby stars. Recent major advances in the understanding of coronagraphic performance and in the field of super smooth mirror fabrication allow such an instrument to be designed and built within current technology. Such a project, called the Circumstellar Imaging Telescope (CIT), is currently being proposed.

  15. A normal incidence, high resolution X-ray telescope for solar coronal observations

    NASA Technical Reports Server (NTRS)

    Golub, L.

    1985-01-01

    The following major activities were advanced or completed: complete design of the entire telescope assembly and fabrication of all front-end components; specification of all rocket skin sections including bulkheads, feedthroughs and access door; fabrication, curing, and delivery of the large graphite-epoxy telescope tube; engineering analysis of the primary mirror vibration test was completed and a decision made to redesign the mirror attachment to a kinematic three-point mount; detail design of the camera control, payload and housekeeping electronics; and multilayer mirror flats with 2d spacings of 50 A and 60 A.

  16. Ion implantation for figure correction of high-resolution x-ray telescope mirrors

    E-print Network

    Chalifoux, Brandon D

    2014-01-01

    Fabricating mirrors for future high-resolution, large-aperture x-ray telescopes continues to challenge the x-ray astronomy instrumentation community. Building a large-aperture telescope requires thin, lightweight mirrors; ...

  17. AAVSO Solar Observers Worldwide

    NASA Astrophysics Data System (ADS)

    Howe, R.

    2013-06-01

    (Abstract only) For visual solar observers there has been no biological change in the "detector" (human eye) - at century scales (eye + visual cortex) does not change much over time. Our capacity to "integrate" seeing distortions is not just simple averaging! The visual cortex plays an essential role, and until recently only the SDO-HMI (Solar Dynamics Observatory, Helioseismic and Magnetic Imager) has had the capacity to detect the smallest sunspots, called pores. Prior to this the eye was superior to photography and CCD. Imaged data are not directly comparable or substitutable to counts by eye, as the effects of sensor/optical resolution and seeing will have a different influence on the resulting sunspot counts for images when compared to the human eye. Also contributing to the complex task of counting sunspots is differentiating between a sunspot (which is usually defined as having a darker center (umbra) and lighter outer ring (penumbra)) and a pore, made even more complex by the conflicting definitions of the word "pore" in the solar context: "pore" can mean a small spot without penumbra or "pore" can mean a random intergranular blemish that is not a true sunspot. The overall agreement is that the smallest spot size is near 2,000 km or ~3 arc sec, (Loughhead, R. E. and Bray, R. J. 1961, Australian J. Phys., 14, 347). Sunspot size is dictated by granulation dynamics rather than spot size (cancellation of convective motion), and by the lifetime of the pore, which averages from 10 to 30 minutes. There is no specific aperture required for AAVSO observers contributing sunspot observations. However, the detection of the smallest spots is influenced by the resolution of the telescope. Two factors to consider are the theoretical optical resolution (unobstructed aperture), Rayleigh criterion: theta = 138 / D(mm), and Dawes criterion: theta = 116 / D(mm) (http://www.telescope-optics.net/telescope_resolution.htm). However, seeing is variable with time; daytime range will be similar for all low-altitude sites, within the range of 1.5 to 3 arc sec, (typically = 2 arc sec equivalent diameter D = 45-90 mm, the typical solar scope = 70 mm aperture). Where large apertures are more affected by size of turbulent eddies ~8-12 cm, small-aperture telescopes reduce these differences, i.e. large aperture is not always beneficial.

  18. Characterisation of rear incident hypervelocity impact phenomena on hubble space telescope solar arrays

    Microsoft Academic Search

    M. K. Herbert

    1999-01-01

    Impact damage on glass faced HST solar cells generated by rear-incident impactors represent over one-third of the total damage on the retrieved solar array. Analysis of such space and laboratory generated morphologies has revealed a means of discriminating between front and rear incident impact sites and enabled characterization through either impactor energy or a simplified indentation fracture model. Morphology is

  19. The Spectrometer Telescope for Imaging X-rays (STIX) on board the Solar Orbiter mission

    E-print Network

    Northwestern Switzerland, Windisch, Switzerland; b Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, Villigen, Switzerland, c ETH ZĂĽrich, Switzerland; d CEA Saclay, France; e LESIA, France; f Space Republic, Austria, and Ireland, with Switzerland as the lead. Space Telescopes and Instrumentation 2012

  20. Submillimeter Telescopes

    NASA Astrophysics Data System (ADS)

    Phillips, Thomas G.; Padin, Stephen; Zmuidzinas, Jonas

    The submillimeter band is a critical one for astronomy. It contains spectral and spatial information on very distant newly formed galaxies and on the early stages of star formation within gas clouds. Yet it is one of the few regions of the electromagnetic spectrum still to be made fully available to astronomy. This is in part due to the general difficulties of construction of detectors, receivers, and telescopes for these wavelengths and in part to the attenuating nature of the Earth's atmosphere. In recent years, optical style telescopes have become available, either on high mountain sites, or in the case of the NASA Kuiper Airborne Observatory (KAO) or Stratospheric Observatory for Infrared Astronomy (SOFIA) on board a high-altitude airplane. The James Clerk Maxwell telescope at 15 m and the Caltech Submillimeter Observatory (CSO) telescope at 10.4 m are both large enough to have developed the field. However, the ESA satellite Herschel has now provided the required space platform for complete spectral coverage and the Atacama Large Millimeter/Submillimeter Array (ALMA) the high spatial resolution, aperture synthesis, high-sensitivity platform.

  1. Analysis of piston error of an optical sparse-aperture imaging system

    Microsoft Academic Search

    Juan Zhao; Dayong Wang; Zhiwei Zhou; Yuhong Wan; Zhuqing Jiang; Shiquan Tao

    2009-01-01

    With the development of Earth and Space missions, the quest for higher spatial resolution for telescopes will turn into urgent need. Optical sparse-aperture system can be designed to obtain high resolution in astronomical object imaging with several independent small-aperture telescopes. However, the images from separated telescopes are not only overlapped but also have same phase. The analysis and discussion on

  2. A Scanning Hartmann Focus Test for the EUVI Telescopes aboard STEREO

    NASA Technical Reports Server (NTRS)

    Ohl, Ray; Antonille, Scott; Aronstein, Dave; Dean, Bruce; Eichhorn, Bil; Frey, Brad; Kubalak, Dave; Shiri, Ron; Smith, Scott; Wilson, Mark; Redman, Kevin; Janssen, Douglas; d'Entremont, Joseph

    2007-01-01

    The Solar TErrestrial RElations Observatory (STEREO), the third mission in NASA's Solar Terrestrial Probes program, was launched in 2006 on a two year mission to study solar phenomena. STEREO consists of two nearly identical satellites, each carrying an Extreme Ultraviolet Imager (EUVI) telescope as part of the Sun Earth Connection Coronal and Heliospheric Investigation instrument suite. EUVI is a normal incidence, 98mm diameter, Ritchey-Chretien telescope designed to obtain wide field of view images of the Sun at short wavelengths (17.1-30.4nm) using a CCD detector. The telescope entrance aperture is divided into four quadrants by a mask near the secondary mirror spider veins. A mechanism that rotates another mask allows only one of these sub-apertures to accept light over an exposure. The EUVI contains no focus mechanism. Mechanical models predict a difference in telescope focus between ambient integration conditions and on-orbit operation. We describe an independent check of the ambient, ultraviolet, absolute focus setting of the EUVI telescopes after they were integrated with their respective spacecraft. A scanning Hartmann-like test design resulted from constraints implied by the EUVI aperture select mechanism. This inexpensive test was simultaneously coordinated with other NASA integration and test activities in a high-vibration, clean room environment. The total focus test error was required to be better than +/-0.05 mm. We describe the alignment and test procedure, sources of statistical and systematic error, and then the focus determination results using various algorithms. The results are consistent with other tests of focus alignment and indicate that the EUVI telescopes meet the ambient focus offset requirements. STEREO is functioning well on-orbit and the EUVI telescopes meet their on-orbit image quality requirements.

  3. Telescopes and space exploration

    NASA Technical Reports Server (NTRS)

    Brandt, J. C.; Maran, S. P.

    1976-01-01

    The necessity for different types of telescopes for astronomical investigations is discussed. Major findings in modern astronomy by ground-based and spaceborne telescopes are presented. Observations of the Crab Nebula, solar flares, interstellar gas, and the Black Hole are described. The theory of the oscillating universe is explored. Operating and planned telescopes are described.

  4. LSST Telescope Design

    Microsoft Academic Search

    V. Krabbendam; C. F. Claver; L. Daggert; J. Sebag; D. R. Neill; R. Gomez; J. H. Burge; R. Tessieries; W. Davison; B. Cuerden

    2004-01-01

    The proposed Large Synoptic Survey Telescope (LSST) has an 8.4 meter aperture with a 3.5 degree diameter field of view and must meet the challenging cadence requirements necessary to perform the LSST survey mission. The telescope optical system is based on a Paul-Baker three element design with a single captured focus for the dedicated instrument. The large mirrors, 8.4 m

  5. Search for Sub-eV Mass Solar Axions by the CERN Axion Solar Telescope with {sup 3}He Buffer Gas

    SciTech Connect

    Arik, M.; Cetin, S. A.; Ezer, C.; Yildiz, S. C. [Dogus University, Istanbul (Turkey); Aune, S.; Ferrer-Ribas, E.; Giomataris, I.; Papaevangelou, T. [IRFU, Centre d'Etudes Nucleaires de Saclay (CEA-Saclay), Gif-sur-Yvette (France); Barth, K.; Borghi, S.; Davenport, M.; Elias, N.; Haug, F.; Laurent, J. M.; Niinikoski, T.; Silva, P. S.; Stewart, L. [European Organization for Nuclear Research (CERN), Geneve (Switzerland); Belov, A.; Gninenko, S. [Institute for Nuclear Research (INR), Russian Academy of Sciences, Moscow (Russian Federation); Braeuninger, H. [Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany)

    2011-12-23

    The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using {sup 3}He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with {sup 4}He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV < or approx. m{sub a} < or approx. 0.64 eV. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g{sub a}{gamma} < or approx. 2.3x10{sup -10} GeV{sup -1} at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m{sub a} < or approx. 1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

  6. Comparison of monochromatic and polychromatic modeling of sparse-aperture image quality

    Microsoft Academic Search

    Robert E. Introne; Noah R. Block; John R. Schott

    2005-01-01

    Optical sparse-aperture (SA) telescopes are a promising new technology to increase the effective diameter of a telescope while reducing its weight and possibly decreasing its stowable size. An SA system is constituted of an array of sub-apertures that are phased to synthesize a telescope with a larger effective diameter than any of the constituent sub-apertures. SAs were first proposed in

  7. Ke Alahaka Program of the Advanced Technology Solar Telescope (ATST) Mitigation Initiative Provides STEM Workshops for Native Hawaiian Students

    NASA Astrophysics Data System (ADS)

    Coopersmith, A.; Cie, D. K.; Naho`olewa, D.; Chirico, J.

    2012-12-01

    The Advanced Technology Solar Telescope (ATST) Mitigation Initiative and the Kahikina O Ka L? Program are NSF-funded projects at the University of Hawai`i Maui College. These projects will provide instruction and activities intended to increase diversity in STEM or STEM-related careers. Ke Alahaka, the 2012 summer bridge program, was offered to Native Hawaiian high-school students who indicated an interest in STEM areas. Three STEM-content workshops were offered including Marine Science, Sustainable Energy Technology, and Computer Science and Engineering. Students attended hands-on classes three days a week for a month concentrating on only one of the three topics. On the other days, students participated in a Hawaiian Studies course designed to provide a cultural context for the STEM instruction. Focus groups and other program assessments indicate that 50% of the 60 students attending the workshops intend to pursue a STEM major during their undergraduate studies.

  8. In-flight performance of the Very high Angular resolution ULtraviolet Telescope sounding rocket payload

    NASA Astrophysics Data System (ADS)

    Korendyke, Clarence M.; Vourlidas, A.; Cook, John W.; Dere, Kenneth P.; Feldman, R.; Howard, Russell A.; Lilley, D. N.; Morrill, Jeff S.; Moses, J. Daniel; Moulton, Norman E.; Moye, Robert W.; Roberts, D. E.; Shepler, E. L.; Smith, J. K.; Socker, Dennis G.; Spears, T. R.; Waymire, R. S.; Brown, Wayne E.; Tarbell, Theodore D.; Berger, Tom; Handy, Brian N.

    2000-12-01

    The Very high Angular Resolution ULtraviolet Telescope experiment was successfully launched on May 7, 1999 on a Black Brant sounding rocket vehicle from White Sands Missile Range. The instrument consists of a 30 cm UV diffraction limited telescope followed by a double grating spectroheliograph tuned to isolate the solar Lyman (alpha) emission line. During the flight, the instrument successfully obtained a series of images of the upper chromosphere with a limiting resolution of approximately 0.33 arc-seconds. The resulting observations are the highest resolution images of the solar atmosphere obtained from space to date. The flight demonstrated that subarc-second ultraviolet images of the solar atmosphere are achievable with a high quality, moderate aperture space telescope and associated optics. Herein, we describe the payload and its in- flight performance.

  9. Lower bound on number and sizes of telescopes in an optical array receiver for deep space optical communication

    NASA Astrophysics Data System (ADS)

    Hashmi, Ali J.; Eftekhar, Ali A.; Adibi, Ali; Amoozegar, Farid

    2014-10-01

    Free-Space optical communication is expected to revolutionize the deep-space communication by providing the high bandwidth data support for future solar and planetary exploration missions. Due to the cost and up-gradation constraints, an earth-based receiver seems to be a viable option. A large telescope acting as an optical antenna is required at the receiver end to support the reasonable data rates (at least in 10s of Mbps range). An array of smaller telescopes connected to fabricate a larger photon-collecting aperture is an attractive architecture. In this research, performance analyses of different array architectures are evaluated for a deep-space interplanetary optical communication link between Mars and Earth with an objective to find a lower bound on the number and sizes of individual telescopes in the array receiver. The achievable data rates are calculated for opposition and conjunction phases of Mars-Earth orbit. Various deleterious factors, such as background noise and atmospheric turbulence are also modeled in the simulations. Total aperture size of various array architectures are kept at 10 m. The comparison of results for different array architectures show that the performance of a receiver employing an array comprising of 135 telescopes with 0.86 m aperture diameter each is almost equivalent to a single telescope with 10 m aperture diameter. Further, if the diameter is reduced below this limit, the performance degradation is substantial.

  10. Optica aperture synthesis

    NASA Astrophysics Data System (ADS)

    van der Avoort, Casper

    2006-05-01

    Optical long baseline stellar interferometry is an observational technique in astronomy that already exists for over a century, but is truly blooming during the last decades. The undoubted value of stellar interferometry as a technique to measure stellar parameters beyond the classical resolution limit is more and more spreading to the regime of synthesis imaging. With optical aperture synthesis imaging, the measurement of parameters is extended to the reconstruction of high resolution stellar images. A number of optical telescope arrays for synthesis imaging are operational on Earth, while space-based telescope arrays are being designed. For all imaging arrays, the combination of the light collected by the telescopes in the array can be performed in a number of ways. In this thesis, methods are introduced to model these methods of beam combination and compare their effectiveness in the generation of data to be used to reconstruct the image of a stellar object. One of these methods of beam combination is to be applied in a future space telescope. The European Space Agency is developing a mission that can valuably be extended with an imaging beam combiner. This mission is labeled Darwin, as its main goal is to provide information on the origin of life. The primary objective is the detection of planets around nearby stars - called exoplanets- and more precisely, Earth-like exoplanets. This detection is based on a signal, rather than an image. With an imaging mode, designed as described in this thesis, Darwin can make images of, for example, the planetary system to which the detected exoplanet belongs or, as another example, of the dust disk around a star out of which planets form. Such images will greatly contribute to the understanding of the formation of our own planetary system and of how and when life became possible on Earth. The comparison of beam combination methods for interferometric imaging occupies most of the pages of this thesis. Additional chapters will treat related subjects, being experimental work on beam combination optics, a description of a novel formalism for aberration retrieval and experimental work on nulling interferometry. The Chapters on interferometric imaging are organized in such a way that not only the physical principles behind a stellar interferometer are clear, but these chapters also form a basis for the method of analysis applied to the interferometers - -or rather beam combination methods- under consideration. The imaging process in a stellar interferometer will be treated as the inversion of a linear system of equations. The definition of interferometric imaging in this thesis can be stated to be the reconstruction of a luminosity distribution function on the sky, that is, in angular measure, larger than the angular diffraction limited spot size -or Point-Spread Function (PSF)- of a single telescope in the array and that contains, again in angular measure, spatial structure that is much smaller than the PSF of a single telescope. This reconstruction has to be based on knowledge of the dimensions of the telescope array and the detector. The detector collects intensity data that is formed by observation of the polychromatic luminosity distribution on the sky and is deteriorated by the quantum-nature of light and an imperfect electronic detection process. Therefore, the imaging study presented in this thesis can be regarded to be a study on the signal characteristics of various interferometers while imaging a polychromatic wide-field stellar source. The collection of beam combination methods under consideration consists of four types. Among these are two well-known types, having either co-axially combined beams as in the Michelson-Morley experiment to demonstrate the existence of ether, or beams that follow optical paths as if an aperture mask were placed in front of a telescope, making the beams combine in the focus of that telescope, as suggested by Fizeau. For separated apertures rather than an aperture mask, these optical paths are stated to be homothetic. In short, these two types wi

  11. Development of the tip-tilt mirror system for the solar XUV telescope

    NASA Astrophysics Data System (ADS)

    Kodeki, Kazuhide; Fukushima, Kazuhiko; Kashiwase, Toshio; Inoue, Masao; Shimizu, Toshifumi; Yoshida, Tsuyoshi; Sakao, Taro; Hara, Hirohisa; Nagata, Shin'ichi; Kano, Ryouhei; Tsuneta, Saku

    1998-08-01

    This paper describes the design and prelaunch performance of the tip-tilt mirror (TTM) system developed for the XUV Cassegrain telescope aboard the ISAS sounding rocket experiment. The spatial resolution of the telescope is about 5 arcsec, whereas the rocket pointing is only controlled to be within +/- 0.5 degree around the target without stability control. The TTM is utilized to stabilize the XUV image on the focal planes by tilting the secondary mirror with two-axes fixed-coil type actuators. The two position- sensitive detectors in the telescope optics and in the TTM mechanical structure from the normal and local closed-loop modes. The TTM has four grain modes with automatic transition among the modes. The low gain mode is used in the initial acquisition, and in case the TTM loses the tracking. The high gain mode is used in the normal tracking mode. This arrangement provides us with the wide initial acquisition angle with single TTM system as well as the high pointing accuracy once the tracking is established. The TTM has a launch-lock mechanism against the launch vibration of 16G. The closed-loop control with command and telemetry interface is done by the flight software against the launch vibration of 16G. The closed-loop control with command and telemetry interface is done by the flight software on the DSP processor. The use of the fast processor brings in the significant reduction in the weight and size of the control- electronics, more flexible control system, and shorter design and testing period.

  12. Feasibility study of a layer-oriented wavefront sensor for solar telescopes: reply.

    PubMed

    Marino, Jose; Wöger, Friedrich

    2014-11-10

    We appreciate the thoughtful comments by Kellerer [Appl. Opt.53, 7643 (2014)10.1364/AO.53.007643] to our recent study [Appl. Opt.53, 685 (2014)10.1364/AO.53.000685] in which we evaluate the practicability of a layer-oriented wavefront sensing approach suggested for use in solar multiconjugate adaptive optics. After careful review of Kellerer's comment, we remain cautious about the feasibility of a solar-layer-oriented Shack-Hartmann wavefront sensor. However, we strongly encourage further analysis and proof-of-concept work that addresses the difficulties outlined in our original paper and that demonstrates the operating principles behind such an instrument. PMID:25402985

  13. The Solar and the Lunar RFI Test for the 40m Radio Telescope

    NASA Astrophysics Data System (ADS)

    Gao, Guan-Nan; Zhang, Xi-Zhen; Su, Yan; Shi, Shuo-Biao; Jin, Wang; Wang, Min

    2008-03-01

    In this paper, the noise temperatures of the Sun and the Moon are measured using the calibrations of the standard radio sources and the standard noise. The authors' conclusions are: (1) If the 40m antenna is pointed to the Sun with the angle >=2°, it will not interfere the DAS (Data Acquisition Subsystem). (2) The lunar noise temperature for 40m telescope is 87.1K, that means, DAS can work normally even when 40m antenna pointing to the Moon exactly.

  14. Radio telescopes of large resolving power

    Microsoft Academic Search

    M. Ryle

    1975-01-01

    The method of aperture synthesis is discussed, and several facilities using the method, as well as some results obtained with them, are described. A brief historical view of the development leading up to the design of aperture synthesis telescopes is given. Apparatus described includes the one-arm, one-movable-point telescope built by Blythe in 1954 and the half-mile, one-mile, and 5-km telescopes.

  15. Doppler winds mapped around the lower thermospheric terminator of Venus: 2012 solar transit observations from the James Clerk Maxwell Telescope

    NASA Astrophysics Data System (ADS)

    Clancy, R. Todd; Sandor, Brad J.; Hoge, James

    2015-07-01

    Doppler shifts of sub-millimeter 12 CO (346 GHz) and 13 CO (330 GHz) and millimeter 12 CO (230 GHz) line absorptions were mapped around the circum-disk terminator of Venus before, during, and after the June 5, 2012 solar transit, employing the James Clerk Maxwell Telescope (JCMT). Radiative transfer analysis of the solar transit 12 CO thermal line absorptions yields cross-terminator winds in the Venus lower thermosphere (100-120 km) over the local time (LT) and latitude extent of the atmospheric limb presented by the inferior conjunction, nightside apparent disk of Venus. The unique solar transit geometry provides enhanced spatial resolution of the terminator (0.2 h in local time, LT) associated with solar illumination of this atmospheric limb region, and so provides the first characterization of the instantaneous distribution of cross terminator flow in the Venus lower thermosphere versus LT and latitude. Furthermore, by mapping Doppler winds over the nightside disk preceding and following the solar transit, we place the highly variable zonal and subsolar-to-antisolar (SSAS) circulation components of the nightside lower thermosphere (Clancy, R.T., Sandor, B.J., Moriarty-Schieven, G.H. [2012a]. Icarus 217, 794-812) in the context of the day-to-night cross terminator flow that drives this chaotic nightside dynamical regime. The solar transit observations indicate substantially supersonic (200-300 m/s) day-to-night cross terminator winds that are significantly (by 50-150 m/s) stronger over the evening versus the morning terminator. They also exhibit surprisingly large (50%) variations over a 1-2 h timescale that challenge explanation. These behaviors likely contribute to both the variability and the apparent retrograde zonal component of circulation in the Venus nightside upper atmosphere. Hence, these observations support dynamical arguments for preferential deceleration of the morning sector SSAS circulation (e.g., Alexander, M.J. [1992]. Geophys. Res. Lett. 19, 2207-2210), as recently simulated in the Venus thermospheric general circulation model of Hoshino et al. (Hoshinom, N. et al. [2013]. J. Geophys. Res. 118, 2004-2015).

  16. The Large Synoptic Survey Telescope

    E-print Network

    Ku?el, Petr

    Synoptic Survey Telescope (LSST) will be a large-aperture, wide-field, ground-based telescope designed interest for cosmology and fundamental physics, LSST will provide tight constraints on the nature of dark considerations that have led to the design of the LSST, and discuss a sampling of the exciting science

  17. The Local Seeing Environment at Big Bear Solar Observatory Angelo Verdoni and Carsten Denker1

    E-print Network

    Bear Lake, Lake Elsinore, Mount Pi~nos, and Lock- wood Valley. In general, the survey determined, Newark, NJ 07102 apv3@njit.edu and cdenker@adm.njit.edu ABSTRACT The site survey for the Advanced the best location for a 4-meter aperture solar telescope. At the end of a four year survey, three sites

  18. Observations of the structure and evolution of solar flares with a soft X-ray telescope

    NASA Technical Reports Server (NTRS)

    Vorpahl, J. A.; Gibson, E. G.; Landecker, P. B.; Mckenzie, D. L.; Underwood, J. M.

    1975-01-01

    Soft X ray flare events were observed with the S-056 X-ray telescope that was part of the ATM complement of instruments aboard SKYLAB. Analyses of these data are reported. The observations are summarized and a detailed discussion of the X-ray flare structures is presented. The data indicated that soft X-ray emitted by a flare come primarily from an intense well-defined core surrounded by a region of fainter, more diffuse emission. An analysis of flare evolution indicates evidence for preliminary heating and energy release prior to the main phase of the flare. Core features are found to be remarkably stable and retain their shape throughout a flare. Most changes in the overall configuration seem to be result of the appearance, disappearance or change in brightness of individual features, rather than the restructuring or reorientation of these features. Brief comparisons with several theories are presented.

  19. The spectrometer/telescope for imaging X-rays on board the ESA Solar Orbiter spacecraft

    NASA Astrophysics Data System (ADS)

    Krucker, S.; Benz, A. O.; Hurford, G. J.; Arnold, N. G.; Orlea?ski, P.; Gröbelbauer, H.-P.; Casadei, D.; Kobler, S.; Iseli, L.; Wiehl, H. J.; Csillaghy, A.; Etesi, L.; Hochmuth, N.; Battaglia, M.; Bednarzik, M.; Resanovic, R.; Grimm, O.; Viertel, G.; Commichau, V.; Howard, A.; Meuris, A.; Limousin, O.; Brun, S.; Vilmer, N.; Skup, K. R.; Graczyk, R.; Stolarski, M.; Michalska, M.; Nowosielski, W.; Cichocki, A.; Mosdorf, M.; Seweryn, K.; Bia?ek, A.; Sylwester, J.; Kowalinski, M.; Mrozek, T.; Podgorski, P.; Mann, G.; Önel, H.; Aurass, H.; Bauer, S.-M.; Bittner, W.; Dionies, F.; Paschke, J.; Plüschke, D.; Popow, E.; Rendtel, J.; Warmuth, A.; Woche, M.; Wolter, D.; Van Beek, H. F.; Farnik, F.; Lin, R. P.

    2013-12-01

    Solar Orbiter is a Sun-observing mission led by the European Space Agency, addressing the interaction between the Sun and the heliosphere. It will carry ten instruments, among them the X-ray imaging spectrometer STIX. STIX will determine the intensity, spectrum, timing, and location of thermal and accelerated electrons near the Sun through their bremsstrahlung X-ray emission. This report gives a brief overview of the STIX scientific goals and covers in more detail the instrument design and challenges.

  20. Cost Modeling for Space Telescope

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2011-01-01

    Parametric cost models are an important tool for planning missions, compare concepts and justify technology investments. This paper presents on-going efforts to develop single variable and multi-variable cost models for space telescope optical telescope assembly (OTA). These models are based on data collected from historical space telescope missions. Standard statistical methods are used to derive CERs for OTA cost versus aperture diameter and mass. The results are compared with previously published models.

  1. Cooling Technology for Large Space Telescopes

    Microsoft Academic Search

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

    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

  2. Aperture masking behind AO systems

    NASA Astrophysics Data System (ADS)

    Ireland, Michael J.

    2012-07-01

    Sparse Aperture-Mask Interferometry (SAM or NRM) behind Adaptive Optics (AO) has now come of age, with more than a dozen astronomy papers published from several 5-10m class telescopes around the world. I will describe the reasons behind its success in achieving relatively high contrasts ( 1000:1 at lambda/ D) and repeatable binary astronomy at the diffraction limit, even when used behind laser-guide star adaptive optics. Placed within the context of AO calibration, the information in an image can be split into pupil-plane phase, Fourier amplitude and closure-phase. It is the closure-phase observable, or its generalisation to Kernel phase, that is immune to pupil-plane phase errors at first and second-order and has been the reason for the technique's success. I will outline the limitations of the technique and the prospects for aperture-masking and related techniques in the future.

  3. Discovery of Finely Structured Dynamic Solar Corona Observed in the Hi-C Telescope

    NASA Technical Reports Server (NTRS)

    Winebarger, A.; Cirtain, J.; Golub, L.; DeLuca, E.; Savage, S.; Alexander, C.; Schuler, T.

    2014-01-01

    In the summer of 2012, the High-resolution Coronal Imager (Hi-C) flew aboard a NASA sounding rocket and collected the highest spatial resolution images ever obtained of the solar corona. One of the goals of the Hi-C flight was to characterize the substructure of the solar corona. We therefore examine how the intensity scales from AIA resolution to Hi-C resolution. For each low-resolution pixel, we calculate the standard deviation in the contributing high-resolution pixel intensities and compare that to the expected standard deviation calculated from the noise. If these numbers are approximately equal, the corona can be assumed to be smoothly varying, i.e. have no evidence of substructure in the Hi-C image to within Hi-C's ability to measure it given its throughput and readout noise. A standard deviation much larger than the noise value indicates the presence of substructure. We calculate these values for each low-resolution pixel for each frame of the Hi-C data. On average, 70 percent of the pixels in each Hi-C image show no evidence of substructure. The locations where substructure is prevalent is in the moss regions and in regions of sheared magnetic field. We also find that the level of substructure varies significantly over the roughly 160 s of the Hi-C data analyzed here. This result indicates that the finely structured corona is concentrated in regions of heating and is highly time dependent.

  4. The Substructure of the Solar Corona Observed in the Hi-C Telescope

    NASA Technical Reports Server (NTRS)

    Winebarger, A.; Cirtain, J.; Golub, L.; DeLuca, E.; Savage, S.; Alexander, C.; Schuler, T.

    2014-01-01

    In the summer of 2012, the High-resolution Coronal Imager (Hi-C) flew aboard a NASA sounding rocket and collected the highest spatial resolution images ever obtained of the solar corona. One of the goals of the Hi-C flight was to characterize the substructure of the solar corona. We therefore calculate how the intensity scales from a low-resolution (AIA) pixels to high-resolution (Hi-C) pixels for both the dynamic events and "background" emission (meaning, the steady emission over the 5 minutes of data acquisition time). We find there is no evidence of substructure in the background corona; the intensity scales smoothly from low-resolution to high-resolution Hi-C pixels. In transient events, however, the intensity observed with Hi-C is, on average, 2.6 times larger than observed with AIA. This increase in intensity suggests that AIA is not resolving these events. This result suggests a finely structured dynamic corona embedded in a smoothly varying background.

  5. THERMAL PROPERTIES OF A SOLAR CORONAL CAVITY OBSERVED WITH THE X-RAY TELESCOPE ON HINODE

    SciTech Connect

    Reeves, Katharine K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St. MS 58, Cambridge, MA 02138 (United States); Gibson, Sarah E. [HAO/NCAR, P.O. Box 3000, Boulder, CO 80307-3000 (United States); Kucera, Therese A. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States); Hudson, Hugh S. [Space Sciences Laboratories, University of California, Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Kano, Ryouhei, E-mail: kreeves@cfa.harvard.edu [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2012-02-20

    Coronal cavities are voids in coronal emission often observed above high latitude filament channels. Sometimes, these cavities have areas of bright X-ray emission in their centers. In this study, we use data from the X-ray Telescope (XRT) on the Hinode satellite to examine the thermal emission properties of a cavity observed during 2008 July that contains bright X-ray emission in its center. Using ratios of XRT filters, we find evidence for elevated temperatures in the cavity center. The area of elevated temperature evolves from a ring-shaped structure at the beginning of the observation, to an elongated structure two days later, finally appearing as a compact round source four days after the initial observation. We use a morphological model to fit the cavity emission, and find that a uniform structure running through the cavity does not fit the observations well. Instead, the observations are reproduced by modeling several short cylindrical cavity 'cores' with different parameters on different days. These changing core parameters may be due to some observed activity heating different parts of the cavity core at different times. We find that core temperatures of 1.75 MK, 1.7 MK, and 2.0 MK (for July 19, July 21, and July 23, respectively) in the model lead to structures that are consistent with the data, and that line-of-sight effects serve to lower the effective temperature derived from the filter ratio.

  6. Mass and Energy of Erupting Solar Plasma Observed with the X-Ray Telescope on Hinode

    NASA Astrophysics Data System (ADS)

    Lee, Jin-Yi; Raymond, John C.; Reeves, Katharine K.; Moon, Yong-Jae; Kim, Kap-Sung

    2015-01-01

    We investigate seven eruptive plasma observations by Hinode/XRT. Their corresponding EUV and/or white light coronal mass ejection features are visible in some events. Five events are observed in several passbands in X-rays, which allows for the determination of the eruptive plasma temperature using a filter ratio method. We find that the isothermal temperatures vary from 1.6 to 10 MK. These temperatures are an average weighted toward higher temperature plasma. We determine the mass constraints of eruptive plasmas by assuming simplified geometrical structures of the plasma with isothermal plasma temperatures. This method provides an upper limit to the masses of the observed eruptive plasmas in X-ray passbands since any clumping causes the overestimation of the mass. For the other two events, we assume the temperatures are at the maximum temperature of the X-ray Telescope (XRT) temperature response function, which gives a lower limit of the masses. We find that the masses in XRT, ~3 × 1013-5 × 1014 g, are smaller in their upper limit than the total masses obtained by LASCO, ~1 × 1015 g. In addition, we estimate the radiative loss, thermal conduction, thermal, and kinetic energies of the eruptive plasma in X-rays. For four events, we find that the thermal conduction timescales are much shorter than the duration of eruption. This result implies that additional heating during the eruption may be required to explain the plasma observations in X-rays for the four events.

  7. Thermal Properties of A Solar Coronal Cavity Observed with the X-Ray Telescope on Hinode

    NASA Technical Reports Server (NTRS)

    Reeves, Katherine K.; Gibson, Sarah E.; Kucera, Theresa A.; Hudson, Hugh S.; Kano, Ryouhei

    2011-01-01

    Coronal cavities are voids in coronal emission often observed above high latitude filament channels. Sometimes, these cavities have areas of bright X-ray emission in their centers. In this study, we use data from the X-ray Telescope (XRT) on the Hinode satellite to examine the thermal emission properties of a cavity observed during July 2008 that contains bright X-ray emission in its center. Using ratios of XRT filters, we find evidence for elevated temperatures in the cavity center. The area of elevated temperature evolves from a ring-shaped structure at the beginning of the observation, to an elongated structure two days later, finally appearing as a compact round source four days after the initial observation. We use a morphological model to fit the cavity emission, and find that a uniform structure running through the cavity does not fit the observations well. Instead, the observations are reproduced by modeling several short cylindrical cavity "cores" with different parameters on different days. These changing core parameters may be due to some observed activity heating different parts of the cavity core at different times. We find that core temperatures of 1.75 MK, 1.7 MK and 2.0 MK (for July 19, July 21 and July 23, respectively) in the model lead to structures that are consistent with the data, and that line-of-sight effects serve to lower the effective temperature derived from the filter ratio.

  8. Toward Active X-ray Telescopes II

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Aldroft, Thomas L.; Atkins, Carolyn; Button, Timothy W.; Cotroneo, Vincenzo; Davis, William N.; Doel, Peter; Feldman, Charlotte H.; Freeman, Mark D.; Gubarev, Mikhail V.; Johnson-Wilke, Raegan L.; Kolodziejczak, Jeffery J.; Lillie, Charles F.; Michette, Alan G.; Ramsey, Brian D.; Reid, Paul B.; Sanmartin, Daniel Rodriguez; Saha, Timo T.; Schwartz, Daniel A.; Trolier-McKinstry, Susan E.; Ulmer, Melville P.; Wilke, Rudeger H. T.; Willingale, Richard; Zhang, William W.

    2012-01-01

    In the half century since the initial discovery of an astronomical (non-solar) x-ray source, the sensitivity for detection of cosmic x-ray sources has improved by ten orders of magnitude. Largely responsible for this dramatic progress has been the refinement of the (grazing-incidence) focusing x-ray telescope. The future of x-ray astronomy relies upon the development of x-ray telescopes with larger aperture areas (greater than 1 m2) and finer angular resolution (less than 1.). Combined with the special requirements of grazing-incidence optics, the mass and envelope constraints of space-borne telescopes render such advances technologically challenging.requiring precision fabrication, alignment, and assembly of large areas (greater than 100 m2) of lightweight (approximately 1 kg m2 areal density) mirrors. Achieving precise and stable alignment and figure control may entail active (in-space adjustable) x-ray optics. This paper discusses relevant programmatic and technological issues and summarizes progress toward active x-ray telescopes.

  9. Rantiga Osservatorio, Tincana (MPC-D03): Observations and searching for small Solar System bodies using a remotely controlled telescope

    NASA Astrophysics Data System (ADS)

    Zolnowski, M.; Kusiak, M.

    2014-07-01

    Rantiga Osservatorio is the first Polish project aimed at discovering and observing small solar-system objects, including near-Earth objects and comets. The observatory officially started in March 2012, as a result of cooperation between two amateur astronomers: Michal Zolnowski and Michal Kusiak. Subsequently, our station received official designation D03 assigned by the IAU's Minor Planet Center. The equipment is installed in northern Italy, on the border between Emilia-Romagna and Tuscany, in the small village of Tincana at an altitude of 643 m. The heart of the observatory is a 0.4-meter reflector f/3.8, mounted on Paramount ME and CCD camera SBIG STX-16803. The equipment is controlled by an industrial computer connected to the internet, and software allowing for automation and remote control of the telescope from Poland. It is also the first Polish amateur observatory which has been used for the discoveries of potentially new asteroids since 1949. Between 2012 and 2013, Rantiga Osservatorio made it possible to submit over 13,000 astrometric measurements of 3,500 asteroids, and we also reported 1,151 candidates for potentially unknown objects. During our presentation, we would like to introduce details of design and several enhancements to allow a convenient and safe way to control an observing session from anywhere in the world using a smartphone.

  10. The Change in Cosmic Ray Intensity Variation with the Solar Wind Velocity (Using GRAPES3 muon narrow angle telescopes and Kiel neutron monitor)

    Microsoft Academic Search

    H. Kojima; Y. Hayashi; K. Hayashi

    2008-01-01

    GRAPES-3 experiment is situated at Ooty in South India 76.7 East 11.4 North. Effective observation area of our muon telescopes is 560 m2. They are the largest detector in the world of its kind. There were several reports that increase of the solar wind velocity suppresses the intensity of cosmic rays. But there are few which studied qualitatively. We have

  11. SYSTEMATIC MOTION OF FINE-SCALE JETS AND SUCCESSIVE RECONNECTION IN SOLAR CHROMOSPHERIC ANEMONE JET OBSERVED WITH THE SOLAR OPTICAL TELESCOPE/HINODE

    SciTech Connect

    Singh, K. A. P.; Nishida, K.; Shibata, K. [Kwasan and Hida Observatories, Graduate School of Science, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Isobe, H., E-mail: singh@kwasan.kyoto-u.ac.jp [Unit for Synergetic Study for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

    2012-11-20

    The Solar Optical Telescope (SOT) on board Hinode allows observations with high spatiotemporal resolution and stable image quality. A {lambda}-shaped chromospheric anemone jet was observed in high resolution with SOT/Hinode. We found that several fine-scale jets were launched from one end of the footpoint to the other. These fine-scale jets ({approx}1.5-2.5 Mm) gradually move from one end of the footpoint to the other and finally merge into a single jet. This process occurs recurrently, and as time progresses the jet activity becomes more and more violent. The time evolution of the region below the jet in Ca II H filtergram images taken with SOT shows that various parts (or knots) appear at different positions. These bright knots gradually merge into each other during the maximum phase. The systematic motion of the fine-scale jets is observed when different knots merge into each other. Such morphology would arise due to the emergence of a three-dimensional twisted flux rope in which the axial component (or the guide field) appears in the later stages of the flux rope emergence. The partial appearance of the knots could be due to the azimuthal magnetic field that appears during the early stage of the flux rope emergence. If the guide field is strong and reconnection occurs between the emerging flux rope and an ambient magnetic field, this could explain the typical feature of systematic motion in chromospheric anemone jets.

  12. Sub-arcsec X-Ray Telescope for Imaging The Solar Corona In the 0.25 - 1.2 keV Band

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis; Cash, Webster; Jelsma, Schuyler; Farmer, Jason

    1996-01-01

    We have developed an X-ray telescope that uses a new technique for focusing X-rays with grazing incidence optics. The telescope was built with spherical optics for all of its components, utilizing the high quality surfaces obtainable when polishing spherical (as opposed to aspherical) optics. We tested the prototype X-ray telescope in the 300 meter vacuum pipe at White Sands Missile Range, NM. The telescope features 2 degee graze angles with tungsten coatings, yielding a bandpass of 0.25-1.5 keV with a peak effective area of 0.8 sq cm at 0.83 keV. Results from X-ray testing at energies of 0.25 keV and 0.93 keV (C-K and Cu-L) verify 0.5 arcsecond performance at 0.93 keV. Results from modeling the X-ray telescope's response to the Sun show that the current design would be capable of recording 10 half arcsecond images of a solar active region during a 300 second NASA sounding rocket flight.

  13. Electron microscope aperture system

    NASA Technical Reports Server (NTRS)

    Heinemann, K. (inventor)

    1976-01-01

    An electron microscope including an electron source, a condenser lens having either a circular aperture for focusing a solid cone of electrons onto a specimen or an annular aperture for focusing a hollow cone of electrons onto the specimen, and an objective lens having an annular objective aperture, for focusing electrons passing through the specimen onto an image plane are described. The invention also entails a method of making the annular objective aperture using electron imaging, electrolytic deposition and ion etching techniques.

  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. The Control System of a Distributed Aperture Imaging Testbed

    Microsoft Academic Search

    Mel Ni; Jean-Noel Aubrun; Mike Bishop; Eric Byler; Howard H. Hamilton; Kenneth R. Lorell; Don Roth; John Thatcher

    2010-01-01

    Star-9 is an experimental demonstration of distributed-aperture imaging built at the Lockheed Martin Advanced Technology Center. White light from a scene generator enters an array of nine telescopes and is combined at a focused image plane. Relative aberrations from each telescope are regulated by a control system using phase diversity and active relay mirrors. A Weiner filter is applied to

  16. High resolution imaging with the James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Clampin, M.

    The James Webb Space Telescope is a large 6 5 meter aperture cryogenic space telescope We discuss the design of the telescope and the primary science goals that motivate the design In particular we highlight the key elements of JWST s architecture and the capabilities of its instrument complement We contrast these capabilities with the next generation of ground-based telescopes

  17. The 5-km Radio Telescope at Cambridge

    Microsoft Academic Search

    Martin Ryle

    1972-01-01

    Radio astronomers can now map the sky with a resolution comparable to that of the best optical telescopes. This latest advance in aperture synthesis technology should yield important new evidence on the physics of radio galaxies, quasars and supernova remnants.

  18. The James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Clampin, M.

    The James Webb Space Telescope is a large 6 5 meter aperture cryogenic space telescope designed to undertake a range of key science observations It driving requirements are presented by the problem of detecting the earliest galaxies We will review the key science goals of JWST and discuss the design of the telescipe in this context We will highlight the key elements of JWST s architecture and the capabilities of its instrument complement and contrast these capabilities with the next generation of ground-based telescopes The current status of the telescope together with recent achievements are reviewed

  19. Parabolic Strip Telescope

    E-print Network

    Chadzitaskos, Goce

    2013-01-01

    We present a proposal of a new type of telescopes using a rotating parabolic strip as the primary mirror. It is the most principal modification of the design of telescopes from the times of Galileo and Newton. In order to demonstrate the basic idea, the image of an artificial constellation observed by this kind of telescope was reconstructed using the techniques described in this article. As a working model of this new telescope, we have used an assembly of the primary mirror---a strip of acrylic glass parabolic mirror 40 cm long and 10 cm wid shaped as a parabolic cylinder of focal length 1 m---and an artificial constellation, a set of 5 apertures in a distance of 5 m illuminated from behind. In order to reconstruct the image, we made a series of snaps, each after a rotation of the constellation by 15 degrees. Using Matlab we reconstructed the image of the artificial constellation.

  20. DAVINCI a Dilute Aperture Coronagraph

    NASA Astrophysics Data System (ADS)

    Shao, Michael

    2009-01-01

    The motivation for DAVINCI was originally to make use of the technology developed for space interferometers like SIM to build a coronagraph from four 1.1m telescopes that was dramatically lower in cost than a 4 5m filled aperture offaxis coronagraph. Our initial studies through team X have shown this cost savings to be real. But a more careful analysis showed that DAVINCI would have an inner working angle of 35mas a factor of 2 smaller than a 2 lambda/D 4 meter coronagraph or 70m external occulter, resulting in a 10X increase in the number of potential Earth-Clone targets. DAVINCI uses a nulling interferometer as a coronagraph, a nulling interferometer is one the few coronagraph architectures that are compatible with segmented and dilute aperture telescopes. Combined with a post coronagraph wavefront sensor several ultra-demanding tolerances of conventional coronagraphs can be relaxed by factors of 100. The post coronagraph wavefront sensor is also much less affected by local and exozodi background than wavefront sensors that use the science camera as the wavefront sensor. The post coronagraph interferometer is also used on ground based extreme AO coronagraphs, GPI, and P1640.

  1. GTC telescope mechanics design

    NASA Astrophysics Data System (ADS)

    Pan Fernandez, Jorge; Asenjo, Consolacion; Orden, Alfredo; Dilla, Angel

    2000-08-01

    The purpose of the Gran Telescopio de CANARIAS (GTC) project is the design, construction, erection and startup of a telescope with a segmented primary mirror equivalent to a circular aperture of 10 m in diameter. The GTC project was created to satisfy the needs of Spanish astronomers for more telescope time and larger telescopes. The GTC project does more than simply increment the list of `8-10 meter class' telescopes. Its requirement for higher specifications differentiates it from other telescopes of its generation. The GTC will combine a large collecting surface with excellent image quality and suitably optimized observation in both the visible and the infrared. The Gran Telescopio de CANARIAS Project Office Telescope Group, based in the Canary Islands, together with a joint venture of Spanish companies, are developing the telescope mechanics systems, taking into account the scientific requirements established. This paper summarizes the scientific requirements that have technically led the design process of the telescope mechanics and the features that have been incorporated to meet said requirements.

  2. The Chromosphere above the sunspot umbra as seen in the New Solar Telescope and Interface Region Imaging Spectrograph

    NASA Astrophysics Data System (ADS)

    Yurchyshyn, Vasyl; Goode, Phil; Abramenko, Valentyna; Kilcik, Ali

    2015-04-01

    Recent observations of sunspot's umbra suggested that it may be finely structured at a sub-arcsecond scale representing a mix of hot and cool plasma elements. In this study we report observations from the New Solar Telescope (NST) of the umbral spikes, which are cool jet-like structures seen in the chromosphere of an umbra. Our analysis indicates that the spikes are not associated with photospheric umbral dots and they tend to occur above darkest parts of the umbra, where magnetic fields are strongest. The spikes exhibit up and down oscillatory motions and their spectral evolution suggests that they might be driven by upward propagating shocks generated by photospheric oscillations.We analyze sunspot oscillations using Interface Region Imaging Spectrograph (IRIS) data and narrow-band NST images and found long term variations in the intensity of chromospheric shocks. Also, sunspot umbral flashes (UFs) appear as narrow bright lanes running along the light bridges (LBs) and clusters of umbral dots (UDs). Time series suggested that UFs preferred to appear on the sunspot-center side of LBs, which may indicate the existence of a compact sub-photospheric driver of sunspot oscillations. We find that the sunspot's umbra appears bright in IRIS images above LBs and UDs. Co-spatial and co-temporal SDO/AIA data showed that these locations were associated with bright footpoints of umbral loops suggesting that LBs may play an important role in heating these loops. The power spectra analysis showed that the intensity of umbral oscillations significantly varies across the umbra and with height, suggesting that umbral non-uniformities and the structure of sunspot magnetic fields may play a role in wave propagation and heating of umbral loops.

  3. Simulated Solar Flare X-Ray and Thermal Cycling Durability Evaluation of Hubble Space Telescope Thermal Control Candidate Replacement Materials

    Microsoft Academic Search

    Kim K. de Groll; Bruce A. Banks; Edward A. Sechkar; David A. Scheiman

    \\u000a During the Hubble Space Telescope (HST) second servicing mission (SM2), astronauts noticed that the multi-layer insulation\\u000a (MLI) covering the telescope was damaged. Large pieces of the outer layer of MLI (aluminized Teflon® fluorinated ethylene\\u000a propylene (Al-FEP)) were cracked in several locations around the telescope. A piece of curled-up Al-FEP was retrieved by the\\u000a astronauts and was found to be severely

  4. Space and lunar-based optical telescopes

    NASA Technical Reports Server (NTRS)

    Stockman, H. S.

    1988-01-01

    The growth of space observatories, especially at optical wavelengths, during the next several decades is considered. It is concluded that large aperture optical telescopes on the Moon, possibly constructed of lunar glasses, will be very competitive with and in some instances superior to Earth orbiting telescopes.

  5. Deployable optical telescope ground demonstration

    Microsoft Academic Search

    Kevin D. Bell; Ruth L. Moser; Michael K. Powers; R. Scott Erwin

    2000-01-01

    The deployable optical telescope, the second project of the Air Force Research Laboratory's Integrated Ground Demonstration Laboratory, will demonstrate critical integration technologies associated with the next generation of beam expanders for space-based laser systems and large apertures for tactical surveillance systems. AFRL's development will be carried in cooperation with the contractor community and have direct ties to the future program

  6. The James Webb Space Telescope

    NASA Technical Reports Server (NTRS)

    Mather, John C.

    2003-01-01

    The James Webb Space Telescope (JWST) will extend the discoveries of the Hubble Space Telescope by deploying a large cooled infrared telescope at the Sun-Earth Lagrange point L2. With a 6 m aperture and three instruments covering the wavelength range from 0.6 to 28 pm, it will provide sensitivities orders of magnitude better than any other facilities. It is intended to observe the light from the first galaxies and the first supernovae, the assembly of galaxies, and the formation and evolution of stars and planetary systems. In this talk I will review the scientific objectives, the hardware concepts and technology, and the predicted system performance.

  7. Rotating Aperture System

    SciTech Connect

    Rusnak, Brian; Hall, James M.; Shen, Stewart; Wood, Richard L.

    2005-01-18

    A rotating aperture system includes a low-pressure vacuum pumping stage with apertures for passage of a deuterium beam. A stator assembly includes holes for passage of the beam. The rotor assembly includes a shaft connected to a deuterium gas cell or a crossflow venturi that has a single aperture on each side that together align with holes every rotation. The rotating apertures are synchronized with the firing of the deuterium beam such that the beam fires through a clear aperture and passes into the Xe gas beam stop. Portions of the rotor are lapped into the stator to improve the sealing surfaces, to prevent rapid escape of the deuterium gas from the gas cell.

  8. THE INFRARED SPECTROGRAPH1 (IRS) ON THE SPITZER SPACE TELESCOPE

    E-print Network

    Galis, Frietson

    THE INFRARED SPECTROGRAPH1 (IRS) ON THE SPITZER SPACE TELESCOPE J. R. Houck,2 T. L. Roellig,3 J science instruments on the Spitzer Space Telescope. The IRS comprises four separate spectrograph modules sensitivity given the 85 cm aperture of the Spitzer Space Telescope (Werner et al. 2004) and the then

  9. Imaging interplanetary CMEs at radio frequency from solar polar orbit

    NASA Astrophysics Data System (ADS)

    Wu, Ji; Sun, Weiying; Zheng, Jianhua; Zhang, Cheng; Liu, Hao; Yan, Jingye; Wang, Chi; Wang, Chuanbing; Wang, Shui

    2011-09-01

    Coronal mass ejections (CMEs) represent a great concentration of mass and energy input into the lower corona. They have come to be recognized as the major driver of physical conditions change in the Sun-Earth system. Consequently, observations of CMEs are important for understanding and ultimately predicting space weather conditions. This paper discusses a proposed mission, the Solar Polar Orbit Radio Telescope (SPORT) mission, which will observe the propagation of interplanetary CMEs to distances of near 0.35 AU from the Sun. The orbit of SPORT is an elliptical solar polar orbit. The inclination angle between the orbit and ecliptic plane should be about 90°. The main payload on board SPORT will be an imaging radiometer working at the meter wavelength band (radio telescope), which can follow the propagation of interplanetary CMEs. The images that are obtained by the radio telescope embody the brightness temperature of the objectives. Due to the very large size required for the antenna aperture of the radio telescope, we adopt interferometric imaging technology to reduce it. Interferometric imaging technology is based on indirect spatial frequency domain measurements plus Fourier transformation. The SPORT spacecraft will also be equipped with a set of optical and in situ measurement instruments such as a EUV solar telescope, a solar wind ion instrument, an energetic particle detector, a magnetometer, a wave detector and a solar radio burst spectrometer.

  10. Hubble Space Telescope, Faint Object Spectrograph

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This drawing illustrates the Hubble Space Telescope's (HST's), Faint Object Spectrograph (FOS). The HST's two spectrographs, the Goddard High-Resolution Spectrograph and the FOS, can detect a broader range of wavelengths than is possible from the Earth because there is no atmosphere to absorb certain wavelengths. Scientists can determine the chemical composition, temperature, pressure, and turbulence of the stellar atmosphere producing the light, all from spectral data. The FOC can detect detail in very faint objects, such as those at great distances, and light ranging from ultraviolet to red spectral bands. Both spectrographs operate in essentially the same way. The incoming light passes through a small entrance aperture, then passes through filters and diffraction gratings, that work like prisms. The filter or grating used determines what range of wavelength will be examined and in what detail. Then the spectrograph detectors record the strength of each wavelength band and sends it back to Earth. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

  11. Sub-Aperture Interferometers

    NASA Technical Reports Server (NTRS)

    Zhao, Feng

    2010-01-01

    Sub-aperture interferometers -- also called wavefront-split interferometers -- have been developed for simultaneously measuring displacements of multiple targets. The terms "sub-aperture" and "wavefront-split" signify that the original measurement light beam in an interferometer is split into multiple sub-beams derived from non-overlapping portions of the original measurement-beam aperture. Each measurement sub-beam is aimed at a retroreflector mounted on one of the targets. The splitting of the measurement beam is accomplished by use of truncated mirrors and masks, as shown in the example below

  12. Neutrino Telescopes

    SciTech Connect

    Carr, John [Centre de Physiques des Particules de Marseille, IN2P3/CNRS (France)

    2005-02-21

    Neutrino telescopes complement gamma ray telescopes in the observations of energetic astronomical sources as well as in searching for the dark matter. This paper gives the status of the current generation neutrino telescopes projects: Baikal, AMANDA, NESTOR, NEMO and ANTARES with particular emphasis on the ANTARES telescope in the Mediterranean Sea.

  13. Space Telescope.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

    This pamphlet describes the Space Telescope, an unmanned multi-purpose telescope observatory planned for launch into orbit by the Space Shuttle in the 1980s. The unique capabilities of this telescope are detailed, the major elements of the telescope are described, and its proposed mission operations are outlined. (CS)

  14. Variable-aperture screen

    DOEpatents

    Savage, G.M.

    1991-10-29

    Apparatus is described for separating material into first and second portions according to size including a plurality of shafts, a plurality of spaced disks radiating outwardly from each of the shafts to define apertures and linkage interconnecting the shafts for moving the shafts toward or away from one another to vary the size of the apertures while the apparatus is performing the separating function. 10 figures.

  15. Did the 28 October 2003 solar flare accelerate protons to (greater-or-similar sign)20 GeV? A study of the subsequent Forbush decrease with the GRAPES3 tracking muon telescope

    Microsoft Academic Search

    T. Nonaka; Y. Hayashi; N. Ito; S. Kawakami; T. Matsuyama; A. Oshima; H. Tanaka; T. Yoshikoshi; S. K. Gupta; A. Jain; S. Karthikeyan; P. K. Mohanty; S. D. Morris; B. S. Rao; K. C. Ravindran; K. Sivaprasad; B. V. Sreekantan; S. C. Tonwar; K. Viswanathan; H. Kojima

    2006-01-01

    Solar flares accelerate charged particles through a variety of mechanisms, which may be constrained through observations at high energies (>10 GeV). We report here a search for direct emission of protons of energy (greater-or-similar sign)20 GeV in association with an X17 class solar flare that occurred on 28 October 2003, using a large area tracking muon telescope of the GRAPES-3

  16. Did the 28 October 2003 solar flare accelerate protons to ≳20GeV? A study of the subsequent Forbush decrease with the GRAPES3 tracking muon telescope

    Microsoft Academic Search

    T. Nonaka; Y. Hayashi; N. Ito; S. Kawakami; T. Matsuyama; A. Oshima; H. Tanaka; T. Yoshikoshi; S. K. Gupta; A. Jain; S. Karthikeyan; P. K. Mohanty; S. D. Morris; B. S. Rao; K. C. Ravindran; K. Sivaprasad; B. V. Sreekantan; S. C. Tonwar; K. Viswanathan; H. Kojima

    2006-01-01

    Solar flares accelerate charged particles through a variety of mechanisms, which may be constrained through observations at high energies (>10GeV). We report here a search for direct emission of protons of energy ≳20GeV in association with an X17 class solar flare that occurred on 28 October 2003, using a large area tracking muon telescope of the GRAPES-3 experiment at Ooty.

  17. Remote sensing space science enabled by the multiple instrument distributed aperture sensor (MIDAS) concept

    Microsoft Academic Search

    Joseph T. Pitman; Alan Duncan; David Stubbs; Robert D. Sigler; Richard L. Kendrick; Eric H. Smith; James E. Mason; Gregory Delory; Jere H. Lipps; Michael Manga; James R. Graham; Imke de Pater; Sarah Reiboldt; Edward Bierhaus; James B. Dalton; James R. Fienup; Jeffrey W. Yu

    2004-01-01

    The science capabilities and features of an innovative and revolutionary approach to remote sensing imaging systems aimed at increasing the return on future planetary science missions many fold are described. Our concept, called Multiple Instrument Distributed Aperture Sensor (MIDAS), provides a large-aperture, wide-field, diffraction-limited telescope at a fraction of the cost, mass and volume of conventional space telescopes, by integrating

  18. Remote Sensing Space Science With The Multiple Instrument Distributed Aperture Sensor (MIDAS) Concept

    Microsoft Academic Search

    J. Pitman; A. Duncan; D. Stubbs; R. Sigler; R. Kendrick; E. Smith; J. Mason; G. Delory; J. H. Lipps; M. Manga; J. Graham; I. dePater; S. Rieboldt; E. Bierhaus; J. B. Dalton; J. Fienup; J. Yu

    2004-01-01

    The science capabilities and features of an innovative and revolutionary approach to remote sensing imaging systems aimed at increasing the return on future planetary science missions like JIMO many fold are described. Our concept, called Multiple Instrument Distributed Aperture Sensor (MIDAS), provides a large-aperture, wide-field, diffraction-limited telescope at a fraction of the cost, mass and volume of conventional space telescopes,

  19. A Space-Based Near-Earth Object Survey Telescope in Support of Human Exploration, Solar System Science, and Planetary Defense

    NASA Technical Reports Server (NTRS)

    Abell, Paul A.

    2011-01-01

    Human exploration of near-Earth objects (NEOs) beginning in 2025 is one of the stated objectives of U.S. National Space Policy. Piloted missions to these bodies would further development of deep space mission systems and technologies, obtain better understanding of the origin and evolution of our Solar System, and support research for asteroid deflection and hazard mitigation strategies. As such, mission concepts have received much interest from the exploration, science, and planetary defense communities. One particular system that has been suggested by all three of these communities is a space-based NEO survey telescope. Such an asset is crucial for enabling affordable human missions to NEOs circa 2025 and learning about the primordial population of objects that could present a hazard to the Earth in the future.

  20. SOLAR MERIDIONAL CIRCULATION FROM DOPPLER SHIFTS OF THE Fe I LINE AT 5250 A AS MEASURED BY THE 150-FOOT SOLAR TOWER TELESCOPE AT THE MT. WILSON OBSERVATORY

    SciTech Connect

    Ulrich, Roger K. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1562 (United States)

    2010-12-10

    Doppler shifts of the Fe I spectral line at 5250 A from the full solar disk obtained over the period 1986 to 2009 are analyzed to determine the circulation velocity of the solar surface along meridional planes. Simultaneous measurements of the Zeeman splitting of this line are used to obtain measurements of the solar magnetic field that are used to select low field points and impose corrections for the magnetically induced Doppler shift. The data utilized is from a new reduction that preserves the full spatial resolution of the original observations so that the circulation flow can be followed to latitudes of 80{sup 0} N/S. The deduced meridional flow is shown to differ from the circulation velocities derived from magnetic pattern movements. A reversed circulation pattern is seen in polar regions for three successive solar minima. A surge in circulation velocity at low latitudes is seen during the rising phases of cycles 22 and 23.

  1. Hubble Space Telescope Optical Telescope Assembly

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This image illustrates the Hubble Space Telescope's (HST's) Optical Telescope Assembly (OTA). One of the three major elements of the HST, the OTA consists of two mirrors (a primary mirror and a secondary mirror), support trusses, and the focal plane structure. The mirrors collect and focus light from selected celestial objects and are housed near the center of the telescope. The primary mirror captures light from objects in space and focuses it toward the secondary mirror. The secondary mirror redirects the light to a focal plane where the Scientific Instruments are located. The primary mirror is 94.5 inches (2.4 meters) in diameter and the secondary mirror is 12.2 inches (0.3 meters) in diameter. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth Orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from the Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The spacecraft is 42.5 feet (13 meters) long and weighs 25,000 pounds (11,600 kilograms). The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

  2. High-energy Gamma-Ray Emission from Solar Flares: Summary of Fermi Large Area Telescope Detections and Analysis of Two M-class Flares

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Albert, A.; Allafort, A.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Bonamente, E.; Bottacini, E.; Bouvier, A.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chen, Q.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Dermer, C. D.; Desiante, R.; Digel, S. W.; Di Venere, L.; Silva, E. do Couto e.; Drell, P. S.; Drlica-Wagner, A.; Favuzzi, C.; Fegan, S. J.; Focke, W. B.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Hayashida, M.; Hays, E.; Horan, D.; Hughes, R. E.; Inoue, Y.; Jackson, M. S.; Jogler, T.; Jóhannesson, G.; Johnson, W. N.; Kamae, T.; Kawano, T.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Murphy, R.; Nemmen, R.; Nuss, E.; Ohno, M.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Perkins, J. S.; Pesce-Rollins, M.; Petrosian, V.; Piron, F.; Pivato, G.; Porter, T. A.; Rainň, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Ritz, S.; Schulz, A.; Sgrň, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Takahashi, H.; Takeuchi, Y.; Tanaka, Y.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tinivella, M.; Tosti, G.; Troja, E.; Tronconi, V.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Werner, M.; Winer, B. L.; Wood, D. L.; Wood, K. S.; Wood, M.; Yang, Z.

    2014-05-01

    We present the detections of 18 solar flares detected in high-energy ?-rays (above 100 MeV) with the Fermi Large Area Telescope (LAT) during its first 4 yr of operation. This work suggests that particle acceleration up to very high energies in solar flares is more common than previously thought, occurring even in modest flares, and for longer durations. Interestingly, all these flares are associated with fairly fast coronal mass ejections (CMEs). We then describe the detailed temporal, spatial, and spectral characteristics of the first two long-lasting events: the 2011 March 7 flare, a moderate (M3.7) impulsive flare followed by slowly varying ?-ray emission over 13 hr, and the 2011 June 7 M2.5 flare, which was followed by ?-ray emission lasting for 2 hr. We compare the Fermi LAT data with X-ray and proton data measurements from GOES and RHESSI. We argue that the ?-rays are more likely produced through pion decay than electron bremsstrahlung, and we find that the energy spectrum of the proton distribution softens during the extended emission of the 2011 March 7 flare. This would disfavor a trapping scenario for particles accelerated during the impulsive phase of the flare and point to a continuous acceleration process at play for the duration of the flares. CME shocks are known for accelerating the solar energetic particles (SEPs) observed in situ on similar timescales, but it might be challenging to explain the production of ?-rays at the surface of the Sun while the CME is halfway to the Earth. A stochastic turbulence acceleration process occurring in the solar corona is another likely scenario. Detailed comparison of characteristics of SEPs and ?-ray-emitting particles for several flares will be helpful to distinguish between these two possibilities.

  3. Telescopic limiting magnitudes

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.

    1990-01-01

    The prediction of the magnitude of the faintest star visible through a telescope by a visual observer is a difficult problem in physiology. Many prediction formulas have been advanced over the years, but most do not even consider the magnification used. Here, the prediction algorithm problem is attacked with two complimentary approaches: (1) First, a theoretical algorithm was developed based on physiological data for the sensitivity of the eye. This algorithm also accounts for the transmission of the atmosphere and the telescope, the brightness of the sky, the color of the star, the age of the observer, the aperture, and the magnification. (2) Second, 314 observed values for the limiting magnitude were collected as a test of the formula. It is found that the formula does accurately predict the average observed limiting magnitudes under all conditions.

  4. KAOS: kilo-aperture optical spectrograph

    NASA Astrophysics Data System (ADS)

    Barden, Samuel C.; Dey, Arjun; Boyle, Brian; Glazebrook, Karl

    2004-09-01

    A design is described for a potential new facility capable of taking detailed spectroscopy of millions of objects in the Universe to explore the complexity of the Universe and to answer fundamental questions relating to the equation of state of dark energy and to how the Milky Way galaxy formed. The specific design described is envisioned for implementation on the Gemini 8-meter telescopes. It utilizes a 1.5° field of view and samples that field with up to ~5000 apertures. This Kilo-Aperture Optical Spectrograph (KAOS) is mounted at prime focus with a 4-element corrector, atmospheric dispersion compensator (ADC), and an Echidna-style fiber optic positioner. The ADC doubles as a wobble plate, allowing fast guiding that cancels out the wind buffeting of the telescope. The fibers, which can be reconfigured in less than 10 minutes, feed to an array of 12 spectrographs located in the pier of the telescope. The spectrographs are capable of provided spectral resolving powers of a few thousand up to about 40,000.

  5. Fluorescence and hybrid detection aperture of the Pierre Auger Observatory

    SciTech Connect

    Bellido, J.A.; D'Urso, D.; Geenen, H.; Guarino, F.; Perrone, L.; Petrera, Sergio; Prado, L., Jr.; Salamida, F.

    2005-07-01

    The aperture of the Fluorescence Detector (FD) of the Pierre Auger Observatory is evaluated from simulated events using different detector configurations: mono, stereo, 3-FD and 4-FD. The trigger efficiency has been modeled using shower profiles with ground impacts in the field of view of a single telescope and studying the trigger response (at the different levels) by that telescope and by its neighbors. In addition, analysis cuts imposed by event reconstruction have been applied. The hybrid aperture is then derived for the Auger final extension. Taking into account the actual Surface Detector (SD) array configuration and its trigger response, the aperture is also calculated for a typical configuration of the present phase.

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

    E-print Network

    Rutten, Rob

    Large fully retractable telescope enclosures still closable in strong wind Felix C.M. Bettonvil a built for the high-resolution solar telescopes DOT (Dutch Open Telescope) and GREGOR, both located the telescopes are in operation. The telescopes and enclosures also operate in hard wind. The prototypes

  7. Design and fabrication of three 1.6-meter telescopes for the Korea Microlensing Telescope Network (KMTNet)

    NASA Astrophysics Data System (ADS)

    Poteet, W. M.; Cauthen, H. K.; Kappler, N.; Kappler, L. G.; Park, Byeong-Gon; Lee, Chung-Uk; Kim, Seung-Lee; Cha, Sang-Mok

    2012-09-01

    The KMTNet telescope Project, sponsored by The Korea Astronomy and Space Science Institute (KASI), is fabricating three wide-field equatorial mount telescopes of 1.6 meter aperture to conduct continuous observations of the Galactic bulge region to search for extra-solar planets. Southern latitude sites secured for these telescopes are SAAO (South Africa), CTIO (Chile), and SSO (Australia). A prime-focus configuration, along with a four-lens corrector achieves the 2.8 degree diagonal FOV. The basic mechanical design utilizes a scaled-up version of the successful 2MASS Telescopes built by the authors in the late 1990's. Scaling up of components has presented challenges requiring several iterations of the detailed mechanical analysis as well as the optical analysis due to interaction with mounting assemblies for the optical components. A flexure-style focus mechanism, driven by three precision actuators, moves the entire headring assembly and provides real-time focus capability, and active primary mirror cooling is implemented for the Zerodur primary. KMTNet engineering specifications are met with the current design, which uses Comsoft's Legacy PCTCS for control. A complete operational telescope and enclosure are scheduled for installation in Tucson, AZ prior to shipping the first hardware to CTIO in order to verify tracking, optical characteristics at various attitudes, and overall observatory functionality. The cameras, being fabricated by The Ohio State University Department of Astronomy, Imaging Sciences Laboratory (ISL), are proceeding in parallel with the telescope fabrication, and that interface is now fixed. Specifics of the mechanical and optical design are presented, along with the current fabrication progress and testing protocols.

  8. The Spitzer Space Telescope Mission

    Microsoft Academic Search

    M. W. Werner; T. L. Roellig; F. J. Low; G. H. Rieke; M. Rieke; W. F. Hoffmann; E. Young; J. R. Houck; B. Brandl; G. G. Fazio; J. L. Hora; R. D. Gehrz; G. Helou; B. T. Soifer; J. Stauffer; J. Keene; P. Eisenhardt; D. Gallagher; T. N. Gautier; W. Irace; C. R. Lawrence; L. Simmons; J. E. Van Cleve; M. Jura; E. L. Wright; D. P. Cruikshank

    2004-01-01

    The Spitzer Space Telescope, NASA's Great Observatory for infrared astronomy, was launched 2003 August 25 and is returning excellent scientific data from its Earth-trailing solar orbit. Spitzer combines the intrinsic sensitivity achievable with a cryogenic telescope in space with the great imaging and spectroscopic power of modern detector arrays to provide the user community with huge gains in capability for

  9. The spitzer space telescope mission

    Microsoft Academic Search

    M. W. Werner

    2005-01-01

    The Spitzer Space Telescope, NASA’s Great Observatory for infrared astronomy, was launched 2003 August 25 and is returning excellent scientific data from its Earth-trailing solar orbit. Spitzer combines the intrinsic sensitivity achievable with a cryogenic telescope in space with the great imaging and spectroscopic power of modern detector arrays to provide the user community with huge gains in capability for

  10. Apollo Telescope Mount Illustration

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Apollo Telescope Mount (ATM) served as the first marned astronomical observatory in space. It was designed for solar research from Earth orbit aboard the Skylab. This image is a cutaway illustration of the ATM canister with callouts and characteristics. The ATM was designed and developed by the Marshall Space Flight Center.

  11. Apollo Telescope Mount Illustration

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The Apollo Telescope Mount (ATM) served as the first marned astronomical observatory in space. It was designed for solar research from Earth orbit aboard the Skylab. This image is a cutaway illustration of the ATM canister. The ATM was designed and developed by the Marshall Space Flight Center.

  12. Apollo Telescope Mount Illustration

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The Apollo Telescope Mount (ATM) served as the first marned astronomical observatory in space. It was designed for solar research from Earth orbit aboard the Skylab. This image is a cutaway illustration of the ATM canister with callouts. The ATM was designed and developed by the Marshall Space Flight Center.

  13. Occultation studies with small telescopes

    NASA Astrophysics Data System (ADS)

    Millis, Robert L.

    The data which can be acquired by observing occultations of stars by asteroids, the Pluto-Charon system, and comets using small telescopes are reviewed. A network of small telescopes may be the only possible means of observing a few specific types of occultations. The occultations are usually sufficiently bright so that small aperture telescopes can easily obtain high signal/noise ratios. The techniques and equipment are accessible to both professional, amateur and student astronomers, which is a favorable situation since only a small percentage of the nearly-hourly occurrence of occultations of stars by minor and distant planetary bodies are ever observed. Techniques employed for measuring the dimensions of asteroids by combining chords measured by distributed small telescopes are described and examples are provided of asteroids for which complete or incomplete size/density mappings have been made.

  14. The James Webb Space Telescope

    NASA Technical Reports Server (NTRS)

    Mather, John C.

    2004-01-01

    The James Webb Space Telescope (JWST) will extend the discoveries of the Hubble Space Telescope (HST) and the Spitzer Space Telescope (SST) by deploying a large cooled infrared telescope around the Sun-Earth Lagrange point L2. With a 6 m aperture and three instruments covering the wavelength range from 0.6 to 28 microns, it will provide sensitivities orders of magnitude better than any other facilities. It is intended to observe the light from the first galaxies and the first supernovae, the assembly of galaxies, and the formation and evolution of stars and planetary systems. In this talk I will review the scientific objectives and the ability of the system to meet them. I will close with a summary of possible future IR space missions, ranging from the far IR to planet-finding coronagraphs and interferometers

  15. Radio telescopes

    Microsoft Academic Search

    J. Findlay

    1964-01-01

    A radio telescope is used in radio astronomy to measure the intensity of the radiation received from various parts of the sky. Such a telescope must be able both to detect and to locate faint radio sources of small angular size, and also to measure the brightness distribution across extended radio sources or over large sky areas. Ideally the telescope

  16. The Falcon Telescope Network

    NASA Astrophysics Data System (ADS)

    Chun, F.; Tippets, R.; Dearborn, M.; Gresham, K.; Freckleton, R.; Douglas, M.

    2014-09-01

    The Falcon Telescope Network (FTN) is a global network of small aperture telescopes developed by the Center for Space Situational Awareness Research in the Department of Physics at the United States Air Force Academy (USAFA). Consisting of commercially available equipment, the FTN is a collaborative effort between USAFA and other educational institutions ranging from two- and four-year colleges to major research universities. USAFA provides the equipment (e.g. telescope, mount, camera, filter wheel, dome, weather station, computers and storage devices) while the educational partners provide the building and infrastructure to support an observatory. The user base includes USAFA along with K-12 and higher education faculty and students. Since the FTN has a general use purpose, objects of interest include satellites, astronomical research, and STEM support images. The raw imagery, all in the public domain, will be accessible to FTN partners and will be archived at USAFA in the Cadet Space Operations Center. FTN users will be able to submit observational requests via a web interface. The requests will then be prioritized based on the type of user, the object of interest, and a user-defined priority. A network wide schedule will be developed every 24 hours and each FTN site will autonomously execute its portion of the schedule. After an observational request is completed, the FTN user will receive notification of collection and a link to the data. The Falcon Telescope Network is an ambitious endeavor, but demonstrates the cooperation that can be achieved by multiple educational institutions.

  17. Study of Rapid Formation of a ? Sunspot Associated with the 2012 July 2 C7.4 Flare Using High-resolution Observations of the New Solar Telescope

    NASA Astrophysics Data System (ADS)

    Wang, Haimin; Liu, Chang; Wang, Shuo; Deng, Na; Xu, Yan; Jing, Ju; Cao, Wenda

    2013-09-01

    Rapid, irreversible changes of magnetic topology and sunspot structure associated with flares have been systematically observed in recent years. The most striking features include the increase of the horizontal field at the polarity inversion line (PIL) and the co-spatial penumbral darkening. A likely explanation of the above phenomenon is the back reaction to the coronal restructuring after eruptions: a coronal mass ejection carries the upward momentum while the downward momentum compresses the field lines near the PIL. Previous studies could only use low-resolution (above 1'') magnetograms and white-light images. Therefore, the changes are mostly observed for X-class flares. Taking advantage of the 0.''1 spatial resolution and 15 s temporal cadence of the New Solar Telescope at the Big Bear Solar Observatory, we report in detail the rapid formation of sunspot penumbra at the PIL associated with the C7.4 flare on 2012 July 2. It is unambiguously shown that the solar granulation pattern evolves to an alternating dark and bright fibril structure, the typical pattern of penumbra. Interestingly, the appearance of such a penumbra creates a new ? sunspot. The penumbral formation is also accompanied by the enhancement of the horizontal field observed using vector magnetograms from the Helioseismic and Magnetic Imager. We explain our observations as being due to the eruption of a flux rope following magnetic cancellation at the PIL. Subsequently, the re-closed arcade fields are pushed down toward the surface to form the new penumbra. NLFFF extrapolation clearly shows both the flux rope close to the surface and the overlying fields.

  18. High-contrast imaging with an arbitrary aperture: Active compensation of aperture discontinuities

    SciTech Connect

    Pueyo, Laurent; Norman, Colin, E-mail: lap@pha.jhu.edu [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD (United States)

    2013-06-01

    We present a new method to achieve high-contrast images using segmented and/or on-axis telescopes. Our approach relies on using two sequential deformable mirrors (DMs) to compensate for the large amplitude excursions in the telescope aperture due to secondary support structures and/or segment gaps. In this configuration the parameter landscape of DM surfaces that yield high-contrast point-spread functions is not linear, and nonlinear methods are needed to find the true minimum in the optimization topology. We solve the highly nonlinear Monge-Ampere equation that is the fundamental equation describing the physics of phase-induced amplitude modulation. We determine the optimum configuration for our two sequential DM system and show that high-throughput and high-contrast solutions can be achieved using realistic surface deformations that are accessible using existing technologies. We name this process Active Compensation of Aperture Discontinuities (ACAD). We show that for geometries similar to the James Webb Space Telescope, ACAD can attain at least 10{sup –7} in contrast and an order of magnitude higher for both the future extremely large telescopes and on-axis architectures reminiscent of the Hubble Space Telescope. We show that the converging nonlinear mappings resulting from our DM shapes actually damp near-field diffraction artifacts in the vicinity of the discontinuities. Thus, ACAD actually lowers the chromatic ringing due to diffraction by segment gaps and struts while not amplifying the diffraction at the aperture edges beyond the Fresnel regime. This outer Fresnel ringing can be mitigated by properly designing the optical system. Consequently, ACAD is a true broadband solution to the problem of high-contrast imaging with segmented and/or on-axis apertures. We finally show that once the nonlinear solution is found, fine tuning with linear methods used in wavefront control can be applied to further contrast by another order of magnitude. Generally speaking, the ACAD technique can be used to significantly improve a broad class of telescope designs for a variety of problems.

  19. Aperture averaging analysis and aperture shape invariance of received scintillation in free-space optical communication links

    NASA Astrophysics Data System (ADS)

    Yuksel, Heba; Davis, Christopher C.

    2006-08-01

    Intensity scintillation and beam wander caused by atmospheric turbulence are two significant phenomena that affect free space optical (FSO) communication links. We have constructed an imaging system for measuring the effects of atmospheric turbulence and obscuration on FSO links. A He-Ne laser beam propagates over a range of 863 meters in atmospheric turbulence conditions that vary diurnally and seasonally from weak to strong. A high performance digital camera with a frame-grabbing computer interface is used to capture received laser intensity distributions at rates up to 30 frames per second and various short shutter speeds, down to 1/16,000s per frame. The captured image frames are analyzed in Labview to evaluate the turbulence index parameter, temporal and spatial intensity variances, and aperture averaging. The aperture averaging results demonstrate the expected reduction in intensity fluctuations with increasing aperture diameter, and show quantitatively the differences in behavior between various strengths of turbulence. This paper will present the most accurate empirical data to date for the weak and intermediate turbulence regime. Such results can help build upon existing empirical data and lead to the development of new theories. Aperture averaging of the received irradiance is also shown to be independent of the shape of the receiver aperture, and depends only on its area. This finding allows the use of refractive or catadioptric receivers, whichever is convenient, and the same amount of aperture averaging will be achieved for equal unobscured aperture areas. This can make the telescope design for an FSO receiver more compact.

  20. Bistatic synthetic aperture radar

    Microsoft Academic Search

    A. M. Horne; G. Yates

    2002-01-01

    Synthetic aperture radar (SAR) is becoming increasingly important in many military ground surveillance and targeting roles because of its ability to operate in all weather, day and night, and to detect, classify and geolocate objects at long stand-off ranges. Bistatic SAR, where the transmitter and receiver are on separate platforms, is seen as a potential means of countering vulnerability. This

  1. Synthetic aperture radiometer systems

    Microsoft Academic Search

    David M. Le Vine

    1999-01-01

    Aperture synthesis is an emerging technology for passive microwave remote sensing from space. It is an interferometric technique similar to earth rotation synthesis employed in radio astronomy in which pairs of small antennas and signal processing are used to obtain the resolution of a single large antenna. The technique has the potential to overcome the barriers that antenna size has

  2. Optica aperture synthesis

    Microsoft Academic Search

    Casper van der Avoort

    2006-01-01

    Optical long baseline stellar interferometry is an observational technique in astronomy that already exists for over a century, but is truly blooming during the last decades. The undoubted value of stellar interferometry as a technique to measure stellar parameters beyond the classical resolution limit is more and more spreading to the regime of synthesis imaging. With optical aperture synthesis imaging,

  3. Apertures & Viewpoints Hank Dietz

    E-print Network

    Dietz, Henry G. "Hank"

    a colorcoded aperture to directly capture a "3D" Anaglyph with a single shot, one lens Apparently used in Vivitar Qdos lens #12;My SingleShot Anaglyphs Anaglyph encodes left/right views by color Impose an appropriately colorshaped PSF and the anaglyph is directly captured Transformation from anaglyph into full

  4. Distributed aperture OFDM radar

    Microsoft Academic Search

    Byung Wook Jung; R aviraj S. Adve; Joohwan Chun

    2009-01-01

    This paper presents a new method of obtaining frequency diversity using orthogonal frequency division multiplexing (OFDM). Exploiting spatial diversity, the key advantage of a distributed aperture radar, requires orthogonality in, for example, the frequency, time, waveform, dimensions across sensors. This paper focuses on the simplest of these cases; frequency orthogonality. Here we address the key drawback associated with frequency diversity:

  5. THE DUTCH OPEN TELESCOPE Robert J. Rutten

    E-print Network

    Rutten, Rob

    Chapter 1 THE DUTCH OPEN TELESCOPE Robert J. Rutten Sterrekundig Instituut Utrecht Postbus 80 000, NL-3508 TA Utrecht, The Netherlands R.J.Rutten@astro.uu.nl Abstract The Dutch Open Telescope (DOT) is an innovative optical solar telescope at the Roque de los Muchachos Observatory in the Canary Islands. Its

  6. FalconSAT-7: a membrane space telescope

    NASA Astrophysics Data System (ADS)

    Andersen, Geoff P.; Asmolova, Olha

    2014-08-01

    The USAF Academy Department of Physics has built FalconSAT-7, a membrane solar telescope to be deployed from a 3U CubeSat in LEO. The primary optic is a 0.2m photon sieve - a diffractive element consisting of billions of tiny circular dimples etched into a Kapton sheet. The membrane, its support structure, secondary optics, two imaging cameras and associated control/recording electronics are all packaged within half the CubeSat volume. Once in space, the supporting pantograph structure is deployed, extending out and pulling the membrane flat under tension. The telescope will then be directed at the Sun to gather images at H-alpha for transmission to the ground. Due for launch in 2015, FalconSAT-7 will serve as a pathfinder for future surveillance missions consisting of a 0.3m aperture deployed from a 12U satellite. Such a telescope would be capable of providing sub-meter resolution of ground-based objects.

  7. SOPHOS -- SOuth Pole High-altitude ObServatory: Aperture Configuration and Imaging Performance

    Microsoft Academic Search

    C. Burrows; R. L. White; P. Bely; H. Ford

    1993-01-01

    SOPHOS is an aerostat-borne, sparsely filled 6-meter optical telescope that we plan to fly in Antartica. This paper presents the results of studies concerning the aperture configuration and the results of simulations of the imaging performance of the telescope. We first describe the results of a computer optimization of the subapertures following a method proposed by T. Cornwell, which consists

  8. Scientific Efficiency of Ground-based Telescopes

    NASA Astrophysics Data System (ADS)

    Abt, Helmut A.

    2012-10-01

    I scanned the six major astronomical journals of 2008 for all 1589 papers that are based on new data obtained from ground-based optical/IR telescopes worldwide. Then I collected data on numbers of papers, citations to them in 3+ years, the most-cited papers, and annual operating costs. These data are assigned to four groups by telescope aperture. For instance, while the papers from telescopes with an aperture >7 m average 1.29 more citations than those with an aperture of 2 to <4 m, this represents a small return for a factor of four difference in operating costs. Among the 17 papers that have received >=100 citations in 3+ years, only half come from the large (>7 m) telescopes. I wonder why the large telescopes do so relatively poorly and suggest possible reasons. I also found that papers based on archival data, such as the Sloan Digital Sky Survey, produce 10.6% as many papers and 20.6% as many citations as those based on new data. Also, the 577.2 papers based on radio data produced 36.3% as many papers and 33.6% as many citations as the 1589 papers based on optical/IR telescopes.

  9. Phase errors in diffraction-limited imaging: contrast limits for sparse aperture masking

    NASA Astrophysics Data System (ADS)

    Ireland, M. J.

    2013-08-01

    Bispectrum phase, closure phase and their generalization to kernel phase are all independent of pupil-plane phase errors to first order. This property, when used with sparse aperture masking behind adaptive optics, has been used recently in high-contrast observations at or inside the formal diffraction limit of large telescopes. Finding the limitations to these techniques requires an understanding of spatial and temporal third-order phase effects, as well as effects such as time-variable dispersion when coupled with the non-zero bandwidths in real observations. In this paper, formulae describing many of these errors are developed, so that a comparison can be made to fundamental noise processes of photon noise and background noise. I show that the current generation of aperture-masking observations of young solar-type stars, taken carefully in excellent observing conditions, are consistent with being limited by temporal phase noise and photon noise. This has relevance for plans to combine pupil remapping with spatial filtering. Finally, I describe calibration strategies for kernel phase, including the optimized calibrator weighting as used for LkCa15, and the restricted kernel phase POISE (phase observationally independent of systematic errors) technique that avoids explicit dependence on calibrators.

  10. Aperture center energy showcase

    SciTech Connect

    Torres, J. J.

    2012-03-01

    Sandia and Forest City have established a Cooperative Research and Development Agreement (CRADA), and the partnership provides a unique opportunity to take technology research and development from demonstration to application in a sustainable community. A project under that CRADA, Aperture Center Energy Showcase, offers a means to develop exhibits and demonstrations that present feedback to community members, Sandia customers, and visitors. The technologies included in the showcase focus on renewable energy and its efficiency, and resilience. These technologies are generally scalable, and provide secure, efficient solutions to energy production, delivery, and usage. In addition to establishing an Energy Showcase, support offices and conference capabilities that facilitate research, collaboration, and demonstration were created. The Aperture Center project focuses on establishing a location that provides outreach, awareness, and demonstration of research findings, emerging technologies, and project developments to Sandia customers, visitors, and Mesa del Sol community members.

  11. Integrated electrochromic aperture diaphragm

    NASA Astrophysics Data System (ADS)

    Deutschmann, T.; Oesterschulze, E.

    2014-05-01

    In the last years, the triumphal march of handheld electronics with integrated cameras has opened amazing fields for small high performing optical systems. For this purpose miniaturized iris apertures are of practical importance because they are essential to control both the dynamic range of the imaging system and the depth of focus. Therefore, we invented a micro optical iris based on an electrochromic (EC) material. This material changes its absorption in response to an applied voltage. A coaxial arrangement of annular rings of the EC material is used to establish an iris aperture without need of any mechanical moving parts. The advantages of this device do not only arise from the space-saving design with a thickness of the device layer of 50?m. But it also benefits from low power consumption. In fact, its transmission state is stable in an open circuit, phrased memory effect. Only changes of the absorption require a voltage of up to 2 V. In contrast to mechanical iris apertures the absorption may be controlled on an analog scale offering the opportunity for apodization. These properties make our device the ideal candidate for battery powered and space-saving systems. We present optical measurements concerning control of the transmitted intensity and depth of focus, and studies dealing with switching times, light scattering, and stability. While the EC polymer used in this study still has limitations concerning color and contrast, the presented device features all functions of an iris aperture. In contrast to conventional devices it offers some special features. Owing to the variable chemistry of the EC material, its spectral response may be adjusted to certain applications like color filtering in different spectral regimes (UV, optical range, infrared). Furthermore, all segments may be switched individually to establish functions like spatial Fourier filtering or lateral tunable intensity filters.

  12. Synthetic aperture wavefront sensing

    NASA Astrophysics Data System (ADS)

    Bará, Salvador; Arines, Justo; Pailos, Eliseo

    2014-06-01

    We propose the synthetic aperture wavefront sensing approach. It is based on acquiring several sets of measurements of the wavefront slopes by displacing sequentially the microlens array with respect to the unknown wavefront. These measurements are stacked together and processed as if obtained with a single-sampling array with an effective number of subpupils equal to the product of the number of microlenses by the number of displacements. We analyze and compare the performance of this approach with the method of modal coefficient averaging. The comparison is made in terms of the squared wavefront reconstruction error, spatially averaged over the pupil and statistically averaged over the noise and the aberrations of the population. We focused our attention on its applications to eye aberrometry. Our numerical results were obtained for a population statistics consistent with a wide sample of young adult eyes using different sampling grids and with several signal-to-noise ratios. They indicate that the synthetic aperture wavefront sensing is affected by less bias and noise propagation than the averaging method, providing smaller mean-squared estimation error. The number of complete Zernike radial orders that can be estimated using the synthetic aperture approach is consistently higher than that allowed by the conventional method.

  13. Synthetic aperture microwave radiometer

    NASA Technical Reports Server (NTRS)

    Levine, D. M.

    1988-01-01

    Realizing the full potential of microwave remote sensing from space requires putting relatively large antennas in orbit. Research is being conducted to develop synthetic aperture antennas to reduce the physical collecting area required of sensors in space, and to possibly open the door to new applications of microwave remote sensing. The technique under investigation involves using a correlation interferometer with multiple baselines. The Microwave Sensors and Data Collection Branch has been engaged in research to develop this technique for applications to remote sensing of soil moisture from space. Soil moisture is important for agricultural applications and for understanding the global hydrologic cycle. An aircraft prototype of an instrument suitable for making such measurements was developed. This is an L-band radiometer called ESTAR which is hoped will become part of the Earth Observing System (EOS). ESTAR is a hybrid instrument which uses both real aperture antennas (long sticks to obtain resolution in the along-track dimension) and aperture synthesis (correlation between sticks to obtain resolution in the cross track dimension). The hybrid was chosen as a compromise to increase the sensitivity (T) of the instrument.

  14. Scanning holographic lidar telescope

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.; Wilkerson, Thomas D.

    1993-01-01

    We have developed a unique telescope for lidar using a holographic optical element (HOE) as the primary optic. The HOE diffracts 532 nm laser backscatter making a 43 deg angle with a normal to its surface to a focus located 130 cm along the normal. The field of view scans a circle as the HOE rotates about the normal. The detector assembly and baffling remain stationary, compared to conventional scanning lidars in which the entire telescope and detector assembly require steering, or which use a large flat steerable mirror in front of the telescope to do the pointing. The spectral bandpass of our HOE is 50 nm (FWHM). Light within that bandpass is spectrally dispersed at 0.6 nm/mm in the focal plane. An aperture stop reduces the bandpass of light reaching the detector from one direction to 1 nm while simultaneously reducing the field of view to 1 mrad. Wavelengths outside the 50 nm spectral bandpass pass undiffracted through HOE to be absorbed by a black backing. Thus, the HOE combines three functions into one optic: the scanning mirror, the focusing mirror, and a narrowband filter.

  15. Conically scanned lidar telescope using holographic optical elements

    Microsoft Academic Search

    Geary K. Schwemmer; Thomas D. Wilkerson

    1992-01-01

    Holographic optical elements (HOE) using volume phase holograms make possible a new class of lightweight scanning telescopes having advantages for lidar remote sensing instruments. So far, the only application of HOE's to lidar has been a non-scanning receiver for a laser range finder. We introduce a large aperture, narrow field of view (FOV) telescope used in a conical scanning configuration,

  16. Double Star Measurements with a Three Inch Tasco Telescope

    NASA Astrophysics Data System (ADS)

    Marble, Stephanie M.; Gonzalez, Christianne M.; Cameron, Corey M.; Johandes, James B.; Chapman, Brett R.; Fishbein, Sarah F.; Johnson, Jolyon M.; White, Robin; Genet, Russell M.

    2008-01-01

    Observations were made of three double stars with known separations and position angles using a three inch 1960's Tasco telescope equipped with a Meade astrometric eyepiece. After these observations were completed, their mean values were compared with cataloged values. It was concluded that, under appropriate conditions, a modest aperture Tasco telescope can provide remarkably accurate and precise results.

  17. Development of the SPIRIT III telescope - From design through test

    Microsoft Academic Search

    Andrew A. Mastandrea; Richard R. Glasheen; James J. Guregian; Roy Esplin

    1993-01-01

    This paper documents the development of the SPIRIT III telescope from the design through its test activities. The SPIRIT III Instrument is the primary infrared instrument on the Mid-Course Space Experiment (MSX). The telescope is an all reflective optical system consisting of twelve mirrors. The nominal collecting apertures is 14 inches. It was designed and built to integrate with a

  18. Solar walk-off protection

    Microsoft Academic Search

    H. Awaya; R. Bedard

    1985-01-01

    A point-focus solar concentrator is normally pointed toward the sun during operations to direct concentrated solar flux into the aperture of the receiver. If solar-tracking control is lost, severe damage may occur when the concentrated solar beam moves, or walks off the aperture across the face of the receiver. Alternative methods of solar walk-off prevention\\/protection for a specific assumed generic

  19. The synthesis radio telescope at Westerbork

    Microsoft Academic Search

    J. W. M. Baars; J. F. van der Brugge; Jean L. Casse; J. P. Hamaker; L. H. Sondaar; J. J. Visser; K. J. Wellington

    1973-01-01

    The synthesis radio telescope (SRT) is an array of 20 simultaneous interferometers formed by 10 fixed and 2 movable antennas on an E-W baseline of 1600 m, operating on the principle of rotational aperture synthesis. It is capable of observing continuum radiation in 4 Stokes parameters and line radiation at 50-, 21-, and 6-cm wavelengths. This paper centers on a

  20. On the Absence of Photospheric Net Currents in Vector Magnetograms of Sunspots Obtained from Hinode (Solar Optical Telescope/Spectro-Polarimeter)

    NASA Astrophysics Data System (ADS)

    Venkatakrishnan, P.; Tiwari, Sanjiv Kumar

    2009-11-01

    Various theoretical and observational results have been reported regarding the presence/absence of net electric currents in the sunspots. The limited spatial resolution of the earlier observations perhaps obscured the conclusions. We have analyzed 12 sunspots observed from Hinode (Solar Optical Telescope/Spectro-polarimeter) to clarify the issue. The azimuthal and radial components of magnetic fields and currents have been derived. The azimuthal component of the magnetic field of sunspots is found to vary in sign with azimuth. The radial component of the field also varies in magnitude with azimuth. While the latter pattern is a confirmation of the interlocking combed structure of penumbral filaments, the former pattern shows that the penumbra is made up of a "curly interlocking combed" magnetic field. The azimuthally averaged azimuthal component is seen to decline much faster than 1/piv in the penumbra, after an initial increase in the umbra, for all the spots studied. This confirms the confinement of magnetic fields and absence of a net current for sunspots as postulated by Parker. The existence of a global twist for a sunspot even in the absence of a net current is consistent with a fibril-bundle structure of the sunspot magnetic fields.

  1. Flare Ribbons Observed with G-band and FeI 6302A Filters of the Solar Optical Telescope on Board Hinode

    E-print Network

    H. Isobe; M. Kubo; T. Minoshima; K. Ichimoto; Y. Katsukawa; T. D. Tarbell; S. Tsuneta; T. E. Berger; B. W. Lites; S. Nagata; T. Shimizu; R. A. Shine; Y. Suematsu; A. Title

    2007-11-26

    The Solar Optical Telescope (SOT) on board Hinode satellite observed an X3.4 class flare on 2006 December 13. Typical two-ribbon structure was observed, not only in the chromospheric CaII H line but also in G-band and FeI 6302A line. The high-resolution, seeing-free images achieved by SOT revealed, for the first time, the sub-arcsec fine structures of the "white light" flare. The G-band flare ribbons on sunspot umbrae showed a sharp leading edge followed by a diffuse inside, as well as previously known core-halo structure. The underlying structures such as umbral dots, penumbral filaments and granules were visible in the flare ribbons. Assuming that the sharp leading edge was directly heated by particle beam and the diffuse parts were heated by radiative back-warming, we estimate the depth of the diffuse flare emission using the intensity profile of the flare ribbon. We found that the depth of the diffuse emission is about 100 km or less from the height of the source of radiative back-warming. The flare ribbons were also visible in the Stokes-V images of FeI 6302A, as a transient polarity reversal. This is probably related to "magnetic transient" reported in the literature. The intensity increase in Stokes-I images indicates that the FeI 6302A line was significantly deformed by the flare, which may cause such a magnetic transient.

  2. Flare Ribbons Observed with G-band and FeI 6302A Filters of the Solar Optical Telescope on Board Hinode

    E-print Network

    Isobe, H; Minoshima, T; Ichimoto, K; Katsukawa, Y; Tarbell, T D; Tsuneta, S; Berger, T E; Lites, B W; Nagata, S; Shimizu, T; Shine, R A; Suematsu, Y; Title, A

    2007-01-01

    The Solar Optical Telescope (SOT) on board Hinode satellite observed an X3.4 class flare on 2006 December 13. Typical two-ribbon structure was observed, not only in the chromospheric CaII H line but also in G-band and FeI 6302A line. The high-resolution, seeing-free images achieved by SOT revealed, for the first time, the sub-arcsec fine structures of the "white light" flare. The G-band flare ribbons on sunspot umbrae showed a sharp leading edge followed by a diffuse inside, as well as previously known core-halo structure. The underlying structures such as umbral dots, penumbral filaments and granules were visible in the flare ribbons. Assuming that the sharp leading edge was directly heated by particle beam and the diffuse parts were heated by radiative back-warming, we estimate the depth of the diffuse flare emission using the intensity profile of the flare ribbon. We found that the depth of the diffuse emission is about 100 km or less from the height of the source of radiative back-warming. The flare ribbo...

  3. Telescope Equipment

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Renaissance Telescope for high resolution and visual astronomy has five 82-degree Field Tele-Vue Nagler Eyepieces, some of the accessories that contribute to high image quality. Telescopes and eyepieces are representative of a family of optical equipment manufactured by Tele-Vue Optics, Inc.

  4. The Galactic Exoplanet Survey Telescope (GEST): A Search for Terrestrial Extra-solar Planets via Gravitational Microlensing

    NASA Astrophysics Data System (ADS)

    Bennett, D. P.; Clampin, M.; Cook, K. H.; Drake, A.; Gould, A.; Horne, K.; Horner, S.; Jewitt, D.; Langston, G.; Lauer, T.; Lumsdaine, A.; Minniti, D.; Peale, S.; Rhie, S. H.; Shao, M.; Stevenson, R.; Tenerelli, D.; Tytler, D.; Woolf, N.

    2000-12-01

    GEST is a comprehensive extra-solar planet search mission sensitive to planets with masses as low as that of Mars. GEST will monitor the Galactic bulge for 8 months per year for three years to detect planets via gravitational microlensing and transits. GEST's microlensing survey will detect low-mass planets at separations of > 0.6 AU via high signal-to-noise variations of gravitational microlensing light curves. These planetary signals do not require follow-up observations to confirm the planetary interpretation, and they yield direct measurements of the star:planet mass ratio. GEST will be able to detect 100 Earth-mass planets at 1 AU (assuming 1 such planet per star) and will detect its first Earth-mass planets within a few months of launch. The GEST microlensing survey is the only proposed planet search program sensitive to old, free-floating planets. GEST's transit survey will search ~ 108 Galactic bulge stars for giant planets at separations of < 30 AU, and it is anticipated that more than 50,000 new giant planets will be discovered. When the Galactic bulge is not visible, GEST will survey ~ 1200 square degrees for Kuiper Belt Objects (KBOs) and operate a Participating Scienctist Program (PSP) with observational programs selected via competitive proposals. The KBO survey should discover 100,000 new KBOs.

  5. The Galactic Exoplanet Survey Telescope (GEST): A Search for Extra-Solar Planets via Gravitational Microlensing and Transits

    NASA Astrophysics Data System (ADS)

    Rhie, S. H.; Bennett, D. P.; Clampin, M.; Cook, K. H.; Drake, A. J.; Gould, A.; Horne, K.; Horner, S. D.; Jewitt, D. C.; Langston, G. I.; Lauer, T. R.; Lumsdaine, A.; Minniti, D.; Peale, S. J.; Shao, M.; Stevenson, R. L.; Tenerelli, D.; Tytler, D.; Woolf, N. J.

    2000-10-01

    GEST is a comprehensive extra-solar planet search mission sensitive to planets with masses as low as that of Mars. GEST will monitor the Galactic bulge for 8 months per year for three years to detect planets via gravitational microlensing and transits. GEST's microlensing survey will detect low-mass planets via high signal-to-noise variations of gravitational microlensing light curves. These planetary signals do not require follow-up observations to confirm the planetary interpretation, and they yield direct measurements of the star:planet mass ratio. GEST will be able to detect ~ 100 Earth-mass planets at 1 AU (assuming ~ 1 such planet per star) and will detect its first Earth-mass planets within a few months of launch. GEST's survey of the Galactic bulge will also detect ~ 50,000 planets via transits. When the Galactic bulge is not visible, GEST will do a Kuiper Belt Object (KBO) survey and operate a Participating Scienctist Program (PSP) with observational programs selected via competitive proposals. It is expected that 100,000 new KBOs will be discovered. The GEST mission can be accomplished at low risk with established technology, and a GEST proposal has been submitted to the current Discovery Competition.

  6. Kilometer scale telescope collector deployable in a shuttle payload

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.

    2004-10-01

    We propose a space telescope that has a diffraction grating as its primary objective element. A membrane grating in the shape of a ribbon could enjoy aperture length above a kilometer. This novel configuration would be particularly useful for very high resolution spectrographic astronomy as required in Doppler shift searches for extra-solar planets due to its very wide aperture in the one dimension used for dispersion and its unprecedented spectral resolving power. Rolls can be stowed in the payload bay for Shuttle delivery into orbit, then unfurled and kept flat using inertial guidance from gyroscopes and centrifugal forces. The large primary collector would not require formation flying since the membrane would provide a mechanical tether. We suggest experiments to establish feasibility of the deployment. We also suggest studies for the tensile mechanics and environmental stresses on the device. Our analysis investigates the parameters of surface flatness, membrane thickness, metallic coating conductivity, grating period, groove blaze and depth. We analyze options for fabrication such as roll embossing of multiple-kilometer length membrane substrates. We also consider an evanescent mode grating in a transmission medium which can be formed using methods now commonplace in telecommunication fiber optics.

  7. 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.

  8. Vertical emitting aperture nanoantennas.

    PubMed

    Yaacobi, Ami; Timurdogan, Erman; Watts, Michael R

    2012-05-01

    Herein we propose, theoretically investigate, and numerically demonstrate a compact design for a vertical emitter at a wavelength of 1.5 ?m based on nanophotonic aperture antennas coupled to a dielectric waveguide. The structure utilizes a plasmonic antenna placed above a Si3N4 waveguide with a ground plane for breaking the up-down symmetry and increasing the emission efficiency. Three-dimensional (3-D) finite-difference time-domain (FDTD) simulations reveal that up to 60% vertical emission efficiency is possible in a structure only four wavelengths long with a 3 dB bandwidth of over 300 nm. PMID:22555702

  9. Parametric Cost Models for Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Henrichs, Todd; Dollinger, Courtney

    2010-01-01

    Multivariable parametric cost models for space telescopes provide several benefits to designers and space system project managers. They identify major architectural cost drivers and allow high-level design trades. They enable cost-benefit analysis for technology development investment. And, they provide a basis for estimating total project cost. A survey of historical models found that there is no definitive space telescope cost model. In fact, published models vary greatly [1]. Thus, there is a need for parametric space telescopes cost models. An effort is underway to develop single variable [2] and multi-variable [3] parametric space telescope cost models based on the latest available data and applying rigorous analytical techniques. Specific cost estimating relationships (CERs) have been developed which show that aperture diameter is the primary cost driver for large space telescopes; technology development as a function of time reduces cost at the rate of 50% per 17 years; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and increasing mass reduces cost.

  10. Transit Detection with a Distributed Network of Telescopes

    NASA Technical Reports Server (NTRS)

    Castellano, T.; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    The discovery since 1995 of more than 80 planets around nearby solar-like stars and the photometric detection of a transit of the planet orbiting HD 209458 (producing a more than 1% drop in brightness that lasts 3 hours) has heralded a new era in astronomy. It has now been demonstrated that small telescopes equipped with sensitive and stable electronic detectors can produce fundamental scientific discoveries regarding the frequency and nature of planets outside the solar system. The modest equipment requirements for the measurement of extrasolar planetary transits are achieved by commercial small aperture telescopes and CCD imagers common among amateur astronomers. With equipment already in hand and armed with target lists, observing techniques and software procedures developed b NASA's Ames Research Center and the University of California at Santa Cruz, non-professional astronomers can contribute significantly to the study of planets around others stars. Statistical analyses of the population of parent stars of the known extrasolar planets indicate that approximately one in ten metal-rich stars should harbor a short-period planet. Given the ten percent chance that a given short-period planet displays transits, we therefore expect that approximately 1% of the most metal rich stars will have a planetary companion detectable by this project. A catalog of 206 highly metal rich nearby F, G and K stars has been compiled, and this catalog will provide a rich source of targets. In addition, main sequence F, G, K and M stars identified to have "transit-like" features in the Hipparcos satellite photometry archive will also be monitored. A commercially available "amateur grade" telescope/CCD/software system acquired late during the 2001 "transit season" for HID 209458 has achieved 0.47% RMS precision for 13 minute time sampling from a suburban backyard under less than ideal observing conditions and a realistic range of airmass values.

  11. A Wide-Field Infrared Camera for the Palomar 200-inch Telescope

    E-print Network

    Galis, Frietson

    A Wide-Field Infrared Camera for the Palomar 200-inch Telescope J. C. Wilsona, S. S. Eikenberrya, C of both large aperture telescopes and large format near-infrared (NIR) detectors are making wide-field NIR that provides the Palomar 200-inch telescope with such an imaging capability. WIRC features a field-of-view (FOV

  12. Real-time correction of atmospherically degraded telescope images through image sharpening

    Microsoft Academic Search

    R. A. Muller; Andrew Buffington

    1974-01-01

    A new technique for the correction of atmospheric distortion in a telescope is presented. Most of this distortion arises from a random phase variation in the incoming light across the telescope aperture. This variation limits the resolving power of even large telescopes to about one second of arc. If one defines the sharpness value of the images in a suitable

  13. Teaching Telescopes

    ERIC Educational Resources Information Center

    Reid, John S.

    1974-01-01

    Discusses experience of teaching optical experiments with emphasis upon the student's design and construction of refracting and reflecting telescopes. Concludes that the student's interest and acquired knowledge are greatly enhanced through the use of realistic experiments. (CC)

  14. Beginning Research with the 1.8-meter Spacewatch Telescope

    NASA Technical Reports Server (NTRS)

    Gehrels, Tom; Lane, Lynn A.

    2001-01-01

    The purpose of this grant was to bring the Spacewatch 1.8-m telescope to operational status for research on asteroids and comets. This objective was achieved; first light with the telescope was in May 2000 and since then several tests and demonstrations of the facility's capability to observe Earth-approaching Asteroids (EAs) have been made, including the first observations to be incorporated into a peer-reviewed publication. The Spacewatch 1.8-m telescope will be the largest in the world dedicated full time to finding and doing astrometry of asteroids and comets. It will be used to search for asteroids and comets anywhere from the space near Earth to regions beyond the orbit of Neptune, and to do astrometry and lightcurves on the fainter of such objects that are already known. Its comparatively large aperture will permit faster discovery of the very small asteroids in Earthlike orbits, such as 1998 KY(sub 26), that are coveted for their accessibility as material resources in space, as well as recovery of EAs on their return apparitions when they tend to be more distant and fainter than they were at the times of their discoveries. It will also tend to find EAs when they do not happen to be close to Earth. Discoveries made under those circumstances allow the objects to be followed for longer intervals, providing better determinations of their orbits during their discovery apparitions. In addition to its size, the 1.8-m Spacewatch telescope will have the unique capability of long strip scanning in any direction, for example along the ecliptic (the plane of the solar system), and along the line of variation of EAs with uncertain orbits that are being targeted for recovery.

  15. Hubble Space Telescope, Goddard High-Resolution Spectrograph

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This drawing illustrates the Hubble Space Telescope's (HST's), Goddard High-Resolution Spectrograph (GHRS). The HST's two spectrographs, the GHRS and the Faint Object Spectrograph (FOS), can detect a broader range of wavelengths than is possible from Earth because there is no atmosphere to absorb certain wavelengths. Scientists can determine the chemical composition, temperature, pressure, and turbulence of the stellar atmosphere producing the light, all from spectral data. The GHRS can detect fine details in the light from somewhat brighter objects but only ultraviolet light. Both spectrographs operate in essentially the same way. The incoming light passes through a small entrance aperture, then passes through filters and diffraction gratings, that work like prisms. The filter or grating used determines what range of wavelength will be examined and in what detail. Then the spectrograph detectors record the strength of each wavelength band and sends it back to Earth. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

  16. The CRTF Real-Time Aperture Flux system

    Microsoft Academic Search

    D. B. Davis

    1980-01-01

    The Real-Time Aperture Flux system (RTAF) is a test measurement system designed to determine the input power\\/unit area (flux density) during solar experiments conducted at the Central Receiver Test Facility, Sandia National Laboratories, Albuquerque, New Mexico. The RTAF is capable of using both thermal sensors and photon sensors to determine the flux densities in the RTAF measuring plane. These data

  17. Optimization of the occulter for the Solar Orbiter/METIS coronagraph

    NASA Astrophysics Data System (ADS)

    Landini, Federico; Vivčs, Sébastien; Romoli, Marco; Guillon, Christophe; Pancrazzi, Maurizio; Escolle, Clement; Focardi, Mauro; Antonucci, Ester; Fineschi, Silvano; Naletto, Giampiero; Nicolini, Gianalfredo; Nicolosi, Piergiorgio; Spadaro, Daniele

    2012-09-01

    METIS (Multi Element Telescope for Imaging and Spectroscopy investigation), selected to fly aboard the Solar Orbiter ESA/NASA mission, is conceived to perform imaging (in visible, UV and EUV) and spectroscopy (in EUV) of the solar corona, by means of an integrated instrument suite located on a single optical bench and sharing the same aperture on the satellite heat shield. As every coronagraph, METIS is highly demanding in terms of stray light suppression. Coronagraphs history teaches that a particular attention must be dedicated to the occulter optimization. The METIS occulting system is of particular interest due to its innovative concept. In order to meet the strict thermal requirements of Solar Orbiter, METIS optical design has been optimized by moving the entrance pupil at the level of the external occulter on the S/C thermal shield, thus reducing the size of the external aperture. The scheme is based on an inverted external-occulter (IEO). The IEO consists of a circular aperture on the Solar Orbiter thermal shield. A spherical mirror rejects back the disk-light through the IEO. A breadboard of the occulting assembly (BOA) has been manufactured in order to perform stray light tests in front of two solar simulators (in Marseille, France and in Torino, Italy). A first measurement campaign has been carried on at the Laboratoire d'Astrophysique de Marseille. In this paper we describe the BOA design, the laboratory set-up and the preliminary results.

  18. Sparse antenna array configurations in large aperture synthesis radio telescopes

    Microsoft Academic Search

    W. A. van Cappellen; S. J. Wijnholds; J. D. Bregman

    2006-01-01

    This paper presents the trade-offs between sparse versus dense and regular versus irregular arrays for the station configuration of the LOFAR low band antenna. The relation between these parameters and the element patterns, station beam patterns, effective area, receiver noise temperature, tapering opportunities and the field of view (or beam width) are presented. A method is proposed and evaluated to

  19. 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-?m wavelengths with imaging and spectroscopic configurations. An overview is presented of the architecture and selected optical design features of JWST are described.

  20. Solar

    NSDL National Science Digital Library

    Iowa Public Television. Explore More Project

    2004-01-01

    What part does solar energy play in satisfying energy demands? This informational piece, part of a series about the future of energy, introduces students to solar energy. Here students read about the uses, benefits, and active and passive methods of solar energy. Information is also presented about limitations, geographical considerations of solar power in the United States, and current uses of solar energy around the world. Thought-provoking questions afford students chances to reflect on what they've read about the uses of solar energy. Articles and information about a solar power plant in the Mohave Desert, the use of solar energy in Iowa, and statistics about solar energy are provided in a sidebar.

  1. Europe discusses role in future space telescope

    NASA Astrophysics Data System (ADS)

    1998-06-01

    Prof. Roger Bonnet said it was important for Europe to make an informed decision in the next few years on whether to support NASA's proposed New Generation Space Telescope (NGST), a follow-on programme to the Hubble Space Telescope. NGST's observing capabilities will far extend the reach of existing ground or space-based telescopes, providing the opportunity for the first time to look back through eons of time to the very first stars and galaxies in the Universe. With an aperture greater than four metres, NGST could also provide European astronomers with a crucial complement to some of ESA's planned future space projects, like FIRST (the Far InfraRed Submillimetre Telescope) and Planck (a mission to study the cosmic background radiation field). NASA and ESA are already involved in preliminary NGST studies but Europe has yet to make a commitment to support the programme. NASA wants to start formal development in 2003, with a launch currently planned for 2007. This week's conference at Liege in Belgium was the first opportunity for many astronomers to exchange ideas and compare technological notes on a Next Generation Space Telescope. It also provided a forum for representatives of Europe's space industry to discuss the technological challenges presented by such a project. Prof. Bonnet said: "From recent experience it is clear that the best scientific results in astronomy and astrophysics are obtained by coordinated observations in different wavelength ranges. "The joint effort of the European space programme and of the various large European ground observatories currently allows European astronomers to be on the front-line of astrophysics research."He said that ESA - if supported programmatically and financially by its member states - is willing to discuss with NASA a mutually fruitful form of NGST participation. But Prof. Bonnet stressed that for this type of collaboration to be approved it remained crucial that the European share contained both scientific and technological "qualifying activities". One possibility is to use one of ESA's "flexi-missions" foreseen in Horizon 2000+, the agency's long term science plan. The Horizon 2000+ report recommends that ESA consider the development of infrared detectors and perform technological studies on lightweight, passively cooled, high optical-quality mirrors for use in the 2-100 micron part of the spectrum. European scientists and astronomers are enthusiastic users of the Hubble Space Telescope, currently occupying some 20 percent of its total observing time. Activities are managed through the European Coordinating Facility (ECF), which was set by ESA at Garching near Munich, Germany, alongside the base of the European Southern Observatory (ESO). In return for a share of Hubble observing time for European astronomers, ESA provided a number of the telescope's key features, including the faint object camera and the solar panels.

  2. Cryogenic system for the infrared space telescope SPICA

    NASA Astrophysics Data System (ADS)

    Sugita, Hiroyuki; Sato, Yoichi; Nakagawa, Takao; Murakami, Hiroshi; Kaneda, Hidehiro; Enya, Keigo; Murakami, Masahide; Tsunematsu, Shoji; Hirabayashi, Masayuki

    2008-07-01

    The SPICA mission has been proposed to JAXA as the second Japanese IR space telescope to be launched in 2017. The SPICA spacecraft, launched with an H-IIA launch vehicle, is to be transferred into a halo orbit around the Sun-Earth L2, where effective radiant cooling is feasible owing to solar rays and radiant heat fluxes from the Earth constantly coming from the same direction. That optimal thermal environment enables this IR space telescope to use a large 3.5-mdiameter- single-aperture primary mirror cooled to 4.5 K with advanced mechanical cryocoolers and effective radiant cooling instead of a massive and short-lived cryogen. As a result of thermal and structural analyses, the thermal design of cryogenic system was obtained. Then, mechanical cryocoolers have been developed to meet cooling requirement at 1.7 K, 4.5 K and 20 K. The latest results of upgrading of the 20 K-class two-stage Stirling cooler, the 4K-class JT cooler, and the 1K-class JT cooler indicate that all cryocoolers gain a sufficient margin of cooling capacity with unprecedentedly low power consumption for the cooling requirement. It is concluded that the feasibility of the SPICA mission was confirmed for the critical cryogenic system design, while some attempts to achieve higher reliability, higher cooling capacity and less vibration have been continued for stable operations throughout the entire mission period.

  3. Material Measurements Using Groundplane Apertures

    NASA Technical Reports Server (NTRS)

    Komisarek, K.; Dominek, A.; Wang, N.

    1995-01-01

    A technique for material parameter determination using an aperture in a groundplane is studied. The material parameters are found by relating the measured reflected field in the aperture to a numerical model. Two apertures are studied which can have a variety of different material configurations covering the aperture. The aperture cross-sections studied are rectangular and coaxial. The material configurations involved combinations of single layer and dual layers with or without a resistive exterior resistive sheet. The resistivity of the resistive sheet can be specified to simulate a perfect electric conductor (PEC) backing (0 Ohms/square) to a free space backing (infinity Ohms/square). Numerical parameter studies and measurements were performed to assess the feasibility of the technique.

  4. Analysis and simulation of aperture-sizing strategies with partial adaptive optics

    NASA Astrophysics Data System (ADS)

    Tyson, Robert K.

    1994-05-01

    The central core intensity of a stellar image observed by a ground-based telescope can be maximized by a judicious balancing of the adaptive optics system and the size of the telescope entrance aperture. For a given aperture, increasing the number of degrees of adaptive optics turbulence compensation will maximize the brightness of the central core. However, for an observatory using an adaptive optics system with a fixed number of degrees-of-freedom, the largest aperture available will not necessarily result in a maximized image central core. The negative effects of atmospheric turbulence, roughly proportional to e(superscript -(D/r(subscript o))(superscript 5/3)), cannot always be compensated by the increased light gathering ability of a larger aperture (proportional to D(superscript 2)). It is shown and verified through simulation that the optimum aperture diameter is a function of N(superscript p) r(subscript o) where N is the number of adaptive optics degrees of freedom and r(subscript o) is the seeing cell size. The simulations show that the exponent p is related to the control algorithm or, more precisely, the figure-of-merit used to drive the deformable mirror actuators. Optimizing the useful aperture of the telescope/adaptive optics system is a strategy that can make use of the variation in site seeing conditions and benefit the astronomer by increasing the available number of observable science objects or reducing the observing time.

  5. Adaptive Full Aperture Wavefront Sensor Study

    NASA Technical Reports Server (NTRS)

    Robinson, William G.

    1997-01-01

    This grant and the work described was in support of a Seven Segment Demonstrator (SSD) and review of wavefront sensing techniques proposed by the Government and Contractors for the Next Generation Space Telescope (NGST) Program. A team developed the SSD concept. For completeness, some of the information included in this report has also been included in the final report of a follow-on contract (H-27657D) entitled "Construction of Prototype Lightweight Mirrors". The original purpose of this GTRI study was to investigate how various wavefront sensing techniques might be most effectively employed with large (greater than 10 meter) aperture space based telescopes used for commercial and scientific purposes. However, due to changes in the scope of the work performed on this grant and in light of the initial studies completed for the NGST program, only a portion of this report addresses wavefront sensing techniques. The wavefront sensing techniques proposed by the Government and Contractors for the NGST were summarized in proposals and briefing materials developed by three study teams including NASA Goddard Space Flight Center, TRW, and Lockheed-Martin. In this report, GTRI reviews these approaches and makes recommendations concerning the approaches. The objectives of the SSD were to demonstrate functionality and performance of a seven segment prototype array of hexagonal mirrors and supporting electromechanical components which address design issues critical to space optics deployed in large space based telescopes for astronomy and for optics used in spaced based optical communications systems. The SSD was intended to demonstrate technologies which can support the following capabilities: Transportation in dense packaging to existing launcher payload envelopes, then deployable on orbit to form a space telescope with large aperture. Provide very large (greater than 10 meters) primary reflectors of low mass and cost. Demonstrate the capability to form a segmented primary or quaternary mirror into a quasi-continuous surface with individual subapertures phased so that near diffraction limited imaging in the visible wavelength region is achieved. Continuous compensation of optical wavefront due to perturbations caused by imperfections, natural disturbances, and equipment induced vibrations/deflections to provide near diffraction limited imaging performance in the visible wavelength region. Demonstrate the feasibility of fabricating such systems with reduced mass and cost compared to past approaches.

  6. Intensity Masking to Get High Resolution Images from Low Quality Apertures

    SciTech Connect

    Theiler, J.P., Priedhorsky, W.C.

    1997-12-31

    The effort and expense required to build and maintain an optical-quality telescope increases dramatically with the size of the telescope aperture, and this is especially so in space. But scenarios have been proposed for deploying (for instance, inflatable) telescopes with very large but considerably lecithin optical-quality apertures. Our interest is in ameliorating the effects of the low quality aperture in order to exploit the raw size of the aperture to obtain high resolution images. We describe an algorithm for generating an adaptive binary mask to correct the time-varying aberrations of very large apertures which are many (possibly hundreds of) wavelengths out of figure. The technique is limited to monochromatic imagery, though the wavelength at which observations are taken can be readily changed on the fly, and for earth-pointing applications, the limited light-gathering power imposed by the monochromatic filter is not a problem. The mask itself can be placed at the exit pupil of the telescope, which permits implementation on a large scale. A similar approach, in which the pixels of the mask are half-wave phase shifters instead of opaque optical elements, was described by Love et al.

  7. Solar Confocal interferometers for Sub-Picometer-Resolution Spectral Filters

    NASA Technical Reports Server (NTRS)

    Gary, G. Allen; Pietraszewski, Chris; West, Edward A.; Dines. Terence C.

    2007-01-01

    The confocal Fabry-Perot interferometer allows sub-picometer spectral resolution of Fraunhofer line profiles. Such high spectral resolution is needed to keep pace with the higher spatial resolution of the new set of large-aperture solar telescopes. The line-of-sight spatial resolution derived for line profile inversions would then track the improvements of the transverse spatial scale provided by the larger apertures. In particular, profile inversion allows improved velocity and magnetic field gradients to be determined independent of multiple line analysis using different energy levels and ions. The confocal interferometer's unique properties allow a simultaneous increase in both etendue and spectral power. The higher throughput for the interferometer provides significant decrease in the aperture, which is important in spaceflight considerations. We have constructed and tested two confocal interferometers. A slow-response thermal-controlled interferometer provides a stable system for laboratory investigation, while a piezoelectric interferometer provides a rapid response for solar observations. In this paper we provide design parameters, show construction details, and report on the laboratory test for these interferometers. The field of view versus aperture for confocal interferometers is compared with other types of spectral imaging filters. We propose a multiple etalon system for observing with these units using existing planar interferometers as pre-filters. The radiometry for these tests established that high spectral resolution profiles can be obtained with imaging confocal interferometers. These sub-picometer spectral data of the photosphere in both the visible and near-infrared can provide important height variation information. However, at the diffraction-limited spatial resolution of the telescope, the spectral data is photon starved due to the decreased spectral passband.

  8. DAVINCI: Dilute Aperture VIsible Nulling Coronagraphic Imager

    NASA Technical Reports Server (NTRS)

    Shao, Michael; Levine, B. M.; Vasisht, G.; Lane, B. F.; Woodruff, R.; Vasudevan, G.; Samuele, R.; Lloyd, C. A.; Clampin, M.; Lyon, R.; Guyon, O.

    2008-01-01

    This slide presentation gives an overview of DAVINCI (Dilute Aperture VIsible Nulling Coronagraphic Imager). The presentation also includes information about dilute aperture coronagraph, and lyot efficiency.

  9. Metrology Requirements of Future X-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    Gubarev, Mikhail

    2010-01-01

    Fundamental needs for future x-ray telescopes: a) Sharp images => excellent angular resolution. b) High throughput => large aperture areas. Generation-X optics technical challenges: a) High resolution => precision mirrors & alignment. b) Large apertures => lots of lightweight mirrors. Innovation needed for technical readiness: a) 4 top-level error terms contribute to image size. b) There are approaches to controlling those errors. Innovation needed for manufacturing readiness: Programmatic issues are at least as severe

  10. Neutrino Telescopes

    SciTech Connect

    Hernandez-Rey, Juan Jose [IFIC - Instituto de Fisica Corpuscular, C.S.I.C. - Universitat de Valencia, E-46071, Valencia (Spain)

    2006-11-28

    We review the present status of high energy neutrino astronomy. The advantages of neutrinos as extra-terrestrial messengers are recalled and their possible extra-terrestrial sources examined. We review as well the status of present and future neutrino telescopes and summarize the results obtained so far in this field.

  11. SHARPI/PICTURE Sounding Rocket Telescope

    NASA Technical Reports Server (NTRS)

    Content, D.; Antonille, S.; Wallace, T.; Rabin, D.; Wake, S.

    2006-01-01

    The Solar High Angular Resolution Photometric Imager (SHARPI)/Planet Imaging Concept Testbed Using a Rocket Experiment (PICTURE) Sounding Rocket Telescope is described. The topics include: 1) Lightweight precision mirror development; 2) Two sounding rocket concepts sharing a telescope; 3) Optical Telescope Assembly (OTA) overview; 4) PM development program; 5) PM figure testing; 6) Mirror coatings; 7) PM mount and verification; 8) Secondary Mirror (SM); and 9) OTA.

  12. Dipole aperture and superconductor requirements

    SciTech Connect

    Wipf, S.L.

    1983-12-11

    The cost of an accelerator is not proportional to the aperture. A change in aperture by a certain percentage results in an overall accelerator cost change by only a fraction of that percentage; the fraction may be between 0.1 and 0.5 and is almost independent of the bending field. This estimate is obtained by analyzing the superconductor requirements as a function of aperture and by making rough estimates of the largest cost items of the accelerator such as magnets and ring tunnel.

  13. Optical-level structural modelling of membrane mirrors for spaceborne telescopes

    E-print Network

    De Blonk, Brett Jeffrey, 1971-

    2003-01-01

    The astronomy and Earth observation communities desire ever-larger space telescopes, but launch costs limit mass and technology limits size. Current research in large aperture mirrors largely supports deployed rigid optics, ...

  14. Minimizing actuator-induced residual error in active space telescope primary mirrors

    E-print Network

    Smith, Matthew William, Ph. D. Massachusetts Institute of Technology

    2010-01-01

    Heritage space telescope mirror technology-i.e. large, monolithic glass primary mirrors-has reached an upper limit on allowable aperture diameter given launch vehicle volume and mass constraints. The next generation of ...

  15. Limits of detection in debris disks around young stars with NaCo/Sparse Aperture Masking observations

    NASA Astrophysics Data System (ADS)

    Gauchet, L.; Lacour, S.

    2014-09-01

    To understand the formation and evolution of solar systems and planets formations in the stars neighbourhood, we need to obtain information of their state at different time of their evolution. Here, we focus on debris disks around young stars aged of ten to few tens of Myr, we analyze NaCo/Sparse Aperture Masking (SAM) observations in the L' band (3.8 ?m) of eight objects (beta Pictoris, AU Mic, 49 Ceti, eta Tel, Fomalhaut, G Lupi, HD182327 and HR8799). The aim is to get limits of detection about the mass of the debris orbiting around their stars. The SAM technique consists in transforming a single telescope into a Fizeau interferometer using a non redundant mask inserted in a pupil plane of the instrument. The analysis of the observations was completed with the sparse aperture mode pipeline. Interference fringes are fitted to obtain complex visibilities of the object, then the closure phases are calibrated and evaluated. Finally, a map of the detection limits is obtained as it is related to the closure phases previously estimated. In order to obtain an estimation of the mass corresponding to the luminosity measured with the reduction pipeline we are using theoretical isochrones interpolated into synthetic color tables. The results are maps of detection limits in unit of Jupiter Mass in a range of up to 450 mas around the stars.

  16. Compressive coded aperture imaging

    NASA Astrophysics Data System (ADS)

    Marcia, Roummel F.; Harmany, Zachary T.; Willett, Rebecca M.

    2009-02-01

    Nonlinear image reconstruction based upon sparse representations of images has recently received widespread attention with the emerging framework of compressed sensing (CS). This theory indicates that, when feasible, judicious selection of the type of distortion induced by measurement systems may dramatically improve our ability to perform image reconstruction. However, applying compressed sensing theory to practical imaging systems poses a key challenge: physical constraints typically make it infeasible to actually measure many of the random projections described in the literature, and therefore, innovative and sophisticated imaging systems must be carefully designed to effectively exploit CS theory. In video settings, the performance of an imaging system is characterized by both pixel resolution and field of view. In this work, we propose compressive imaging techniques for improving the performance of video imaging systems in the presence of constraints on the focal plane array size. In particular, we describe a novel yet practical approach that combines coded aperture imaging to enhance pixel resolution with superimposing subframes of a scene onto a single focal plane array to increase field of view. Specifically, the proposed method superimposes coded observations and uses wavelet-based sparsity recovery algorithms to reconstruct the original subframes. We demonstrate the effectiveness of this approach by reconstructing with high resolution the constituent images of a video sequence.

  17. Sparse aperture endoscope

    DOEpatents

    Fitch, J.P.

    1999-07-06

    An endoscope is disclosed which reduces the volume needed by the imaging part, maintains resolution of a wide diameter optical system, while increasing tool access, and allows stereographic or interferometric processing for depth and perspective information/visualization. Because the endoscope decreases the volume consumed by imaging optics such allows a larger fraction of the volume to be used for non-imaging tools, which allows smaller incisions in surgical and diagnostic medical applications thus produces less trauma to the patient or allows access to smaller volumes than is possible with larger instruments. The endoscope utilizes fiber optic light pipes in an outer layer for illumination, a multi-pupil imaging system in an inner annulus, and an access channel for other tools in the center. The endoscope is amenable to implementation as a flexible scope, and thus increases it's utility. Because the endoscope uses a multi-aperture pupil, it can also be utilized as an optical array, allowing stereographic and interferometric processing. 7 figs.

  18. Single-variable parametric cost models for space telescopes

    NASA Astrophysics Data System (ADS)

    Stahl, H. Philip; Henrichs, Todd; Smart, Christian; Prince, Frank A.

    2010-07-01

    Parametric cost models are routinely used to plan missions, compare concepts, and justify technology investments. Unfortunately, there is no definitive space telescope cost model. For example, historical cost estimating relationships (CERs) based on primary mirror diameter vary by an order of magnitude. We present new single-variable cost models for space telescope optical telescope assembly (OTA). They are based on data collected from 30 different space telescope missions. Standard statistical methods are used to derive CERs for OTA cost versus aperture diameter and mass. The results are compared with previously published models

  19. Status of the James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Clampin, Mark; Bowers, C.

    2010-01-01

    The James Webb Space Telescope is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments. JWST's primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, protoplanetary systems, and the formation of evolution of planetary systems. JWST has entered its implementation phase during which the observatory is built, integrated and tested. In the last six months JWST has accomplished critical design reviews (CDR) for the telescope and sunshield. We will present an overview of the JWST observatory and report on recent progress with the key observatory sub-systems: the telescope, sunshield and the spacecraft. We review current predictions for observatory performance based on the CDR performance, and discuss plans for the verification of JWST's performance by means of cryogenic testing prior to launch in 2014.

  20. Large aperture optical switching devices

    SciTech Connect

    Goldhar, J.; Henesian, M.A.

    1983-12-12

    We have developed a new approach to constructing large aperture optical switches for next generation inertial confinement fusion lasers. A transparent plasma electrode formed in low pressure ionized gas acts as a conductive coating to allow the uniform charging of the optical faces of an electro-optic material. In this manner large electric fields can be applied longitudinally to large aperture, high aspect ratio Pockels cells. We propose a four-electrode geometry to create the necessary high conductivity plasma sheets, and have demonstrated fast (less than 10 nsec) switching in a 5x5 cm aperture KD*P Pockels cell with such a design. Detaid modelling of Pockels cell performance with plasma electrodes has been carried out for 15 and 30 cm aperture designs.

  1. Science Promise and Conceptual Mission Design for SAFIR - the Single Aperture Far Infrared Observatory

    NASA Technical Reports Server (NTRS)

    Lester, Dan; Benford, Dominic; Yorke, Harold W.; Bradford, Charles. M.; Parrish, Keith; Stahl, H.

    2006-01-01

    We report on completion of the SAFIR Vision Mission study, as organized by the NASA Science Mission Directorate. This study resulted in a focused baseline design for this large aperture space observatory that capitalizes on architectures being actively developed for JWST and other missions. Special opportunities for achieving thermal performance of this <10K telescope are reviewed, as well as efforts to understand capabilities and needs for focal plane instrument and I&T on this large (10m-class) telescope.

  2. RF/optical shared aperture for high availability wideband communication RF/FSO links

    DOEpatents

    Ruggiero, Anthony J; Pao, Hsueh-yuan; Sargis, Paul

    2014-04-29

    An RF/Optical shared aperture is capable of transmitting and receiving optical signals and RF signals simultaneously. This technology enables compact wide bandwidth communications systems with 100% availability in clear air turbulence, rain and fog. The functions of an optical telescope and an RF reflector antenna are combined into a single compact package by installing an RF feed at either of the focal points of a modified Gregorian telescope.

  3. Hubble Space Telescope-Illustration

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This is a cutaway illustration of the Hubble Space Telescope (HST) with callouts. The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is approximately the size of a railroad car, with two cylinders joined together and wrapped in a silvery reflective heat shield blanket. Wing-like solar arrays extend horizontally from each side of these cylinders, and dish-shaped anternas extend above and below the body of the telescope. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

  4. Hubble Space Telescope-Illustration

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This illustration depicts a side view of the Hubble Space Telescope (HST). The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is approximately the size of a railroad car, with two cylinders joined together and wrapped in a silvery reflective heat shield blanket. Wing-like solar arrays extend horizontally from each side of these cylinders, and dish-shaped anternas extend above and below the body of the telescope. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

  5. Astronomical telescope with holographic primary objective

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.; Friedman, Jeffrey F.; Content, David A.

    2011-09-01

    A dual dispersion telescope with a plane grating primary objective was previously disclosed that can overcome intrinsic chromatic aberration of dispersive optics while allowing for unprecedented features such as million object spectroscopy, extraordinary étendue, flat primary objective with a relaxed figure tolerance, gossamer membrane substrate stowable as an unsegmented roll inside a delivery vehicle, and extensibility past 100 meter aperture at optical wavelengths. The novel design meets many criteria for space deployment. Other embodiments are suitable for airborne platforms as well as terrestrial and lunar sites. One problem with this novel telescope is that the grazing exodus configuration necessary to achieve a large aperture is traded for throughput efficiency. Now we show how the hologram of a point source used in place of the primary objective plane grating can improve efficiency by lowering the diffraction angle below grazing exodus. An intermediate refractive element is used to compensate for wavelength dependent focal lengths of the holographic primary objective.

  6. SNAP Telescope

    Microsoft Academic Search

    Michael J. Sholl; Michael L. Lampton; W. Althouse; R. Amanullah; James T. Annis; Pierre Astier; Charles Baltay; G. Bernstein; Stephane Basa; Christopher J. Bebek; Lars Bergstrom; Manfred Bester; Bruce C. Bigelow; Roger Blandford; Ralph C. Bohlin; Alain Bonissent; Charles R. Bower; Mark L. Brown; Myron Campbell; William C. Carithers Jr.; Eugene D. Commins; D. Hardin; S. Harris; F. DeJongh; Susana E. Deustua; S. Holland; S. Dodelson; Anne Ealet; Richard S. Ellis; W. Emmet; D. Fouchez; Josh Frieman; Andrew Fruchter; D. Gerdes; L. Gladney; Gerson Goldhaber; Ariel Goobar; Donald E. Groom; Henry D. Heetderks; T. McKay; M. Metzger; R. Miquel; Dragan Huterer; P. Nugent; Patrick N. Jelinsky; Armin Karcher; C. Pennypacker; Steven M. Kent; A. Refregier; William F. Kolbe; K. Robinson; K. Schahmaneche; N. Kuznetsova; Robin E. Lafever; J. I. Lamoureux; Olivier Le Fevre; Michael E. Levi; A. Tomasach; Huan Lin; Eric V. Linder; Stewart C. Loken; W. Lorenzon; Roger Malina; J. Marriner; P. Marshall; R. Massey; Alain Mazure; Shawn P. McKee; Nicholas Morgan; E. Mörtsell; Nick Mostek; Stuart Mufson; J. A. Musser; Hakeem M. Oluseyi; Reynald Pain; Nick P. Palaio; David H. Pankow; John Peoples Jr.; Saul Perlmutter; Eric Prieto; David Rabinowitz; Jason Rhodes; Natalie A. Roe; D. Rusin; V. Scarpine; Michael S. Schubnell; Gérard Smadja; Roger M. Smith; George F. Smoot; Jeffrey A. Snyder; Anthony Spadafora; A. Stebbins; Christopher Stoughton; Andrew Szymkowiak; Gregory Tarlé; Keith Taylor; A. Tilquin; Andrew D. Tomasch; Douglas Tucker; D. Vincent; Henrik von der Lippe; Jean-Pierre Walder; Guobin Wang; W. Wester

    2005-01-01

    To probe theoretical models of dark energy and predictions of the expansion of the universe, observational techniques are needed that offer reduced random and systematic errors. The SuperNova Acceleration Probe (SNAP) is a spaceborne observatory to study dark energy using type Ia supernovae and gravitational weak lensing. We have baselined a two-meter-class all-reflecting telescope of the annular-field three mirror anastigmat

  7. SNAP Telescope

    Microsoft Academic Search

    Michael L. Lampton; Carl W. Akerlof; Greg Aldering; R. Amanullah; Pierre Astier; E. Barrelet; Christopher Bebek; Lars Bergstrom; John Bercovitz; G. Bernstein; Manfred Bester; Alain Bonissent; C. R. Bower; William C. Carithers Jr.; Eugene D. Commins; C. Day; Susana E. Deustua; Richard S. DiGennaro; Anne Ealet; Richard S. Ellis; Mikael Eriksson; Andrew Fruchter; Jean-Francois Genat; Gerson Goldhaber; Ariel Goobar; Donald E. Groom; Stewart E. Harris; Peter R. Harvey; Henry D. Heetderks; Steven E. Holland; Dragan Huterer; Armin Karcher; Alex G. Kim; William F. Kolbe; B. Krieger; R. Lafever; J. Lamoureux; Michael E. Levi; Daniel S. Levin; Eric V. Linder; Stewart C. Loken; Roger Malina; R. Massey; Timothy McKay; Shawn P. McKee; Ramon Miquel; E. Mortsell; N. Mostek; Stuart Mufson; J. A. Musser; Peter E. Nugent; Hakeem M. Oluseyi; Reynald Pain; Nicholas P. Palaio; David H. Pankow; Saul Perlmutter; R. Pratt; Eric Prieto; Alexandre Refregier; J. Rhodes; Kem E. Robinson; N. Roe; Michael Sholl; Michael S. Schubnell; G. Smadja; George F. Smoot; A. Spadafora; Gregory Tarle; Andrew D. Tomasch; H. von der Lippe; R. Vincent; J.-P. Walder; Guobin Wang

    2002-01-01

    The SuperNova\\/Acceleration Probe (SNAP) mission will require a two-meter class telescope delivering diffraction limited images spanning a one degree field in the visible and near infrared wavelength regime. This requirement, equivalent to nearly one billion pixel resolution, places stringent demands on its optical system in terms of field flatness, image quality, and freedom from chromatic aberration. We discuss the advantages

  8. Bistatic synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Yates, Gillian

    Synthetic aperture radar (SAR) allows all-weather, day and night, surface surveillance and has the ability to detect, classify and geolocate objects at long stand-off ranges. Bistatic SAR, where the transmitter and the receiver are on separate platforms, is seen as a potential means of countering the vulnerability of conventional monostatic SAR to electronic countermeasures, particularly directional jamming, and avoiding physical attack of the imaging platform. As the receiving platform can be totally passive, it does not advertise its position by RF emissions. The transmitter is not susceptible to jamming and can, for example, operate at long stand-off ranges to reduce its vulnerability to physical attack. This thesis examines some of the complications involved in producing high-resolution bistatic SAR imagery. The effect of bistatic operation on resolution is examined from a theoretical viewpoint and analytical expressions for resolution are developed. These expressions are verified by simulation work using a simple 'point by point' processor. This work is extended to look at using modern practical processing engines for bistatic geometries. Adaptations of the polar format algorithm and range migration algorithm are considered. The principal achievement of this work is a fully airborne demonstration of bistatic SAR. The route taken in reaching this is given, along with some results. The bistatic SAR imagery is analysed and compared to the monostatic imagery collected at the same time. Demonstrating high-resolution bistatic SAR imagery using two airborne platforms represents what I believe to be a European first and is likely to be the first time that this has been achieved outside the US (the UK has very little insight into US work on this topic). Bistatic target characteristics are examined through the use of simulations. This also compares bistatic imagery with monostatic and gives further insight into the utility of bistatic SAR.

  9. James Webb Space Telescope: The First Light Machine

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2014-01-01

    NASA James Webb Space Telescope (JWST) will search for the first luminous objects of the Universe to help answer fundamental questions about how the Universe came to look like it does today. At 6.5 meters in diameter, JWST will be the world's largest space telescope. Its architecture, e.g. aperture, wavelength range and operating temperature, is driven by JWST's science objectives. Introduction: Scheduled to start its 5 year mission after 2018, JWST will study the origin and evolution of galaxies, stars and planetary systems. Its science mission is to: Identify the first bright objects that formed in the early Universe, and follow the ionization history. Determine how galaxies form. Determine how galaxies and dark matter, including gas, stars, metals, overall morphology and active nuclei evolved to the present day. Observe the birth and early development of stars and the formation of planets. And, study the physical and chemical properties of solar systems for the building blocks of Life. Principle: To accomplish the JWST science objectives requires a larger aperture infrared cryogenic space telescope. A large aperture is required because the objects are very faint. The infrared spectral range is required because the objects are so far away that their ultraviolet and visible wavelength spectral lines are red-shifted into the infrared. Because the telescope is infrared, it needs to be cryogenic. And, because of the telescope is infrared, it must operate above the Earth's atmosphere, i.e. in space. JWST is probably the single most complicated mission that humanity has attempted. It is certainly the most difficult optical fabrication and testing challenge of our generation. The JWST 6.5 m diameter primary mirror is nearly a parabola with a conic constant of -0.9967 and radius of curvature at 30K of 15.880 m. The primary mirror is divided into 18 segments with 3 different prescriptions; each with its own off-axis distance and aspheric departure. The radius of curvature for all 18 segments must match to +/- 0.150 mm at 30K. JWST is diffraction limited at 2 micrometers which translates into a transmitted wavefront specification of 156 nm rms. Of that amount, 50 nm rms is allocated to the primary mirror. Each segment is allocated 22 nm rms surface error. At the start of the JWST program, the capability to make such a mirror did not exist. In 1996, NASA began a systematic and comprehensive mirror technology development effort which resulted in JWST. This program resulted in a qualified mirror fabrication process being approved in 2006. Today, all JWST primary mirror segments meet their requirements and are on schedule for a 2018 launch. The next step is system level assembly, integration and test. Ambient tests will be conducted at Goddard Space Flight Center and cryogenic system level testing will be performed in Chamber A at the Johnson Space Center.

  10. MOTESS Solar System Observations: Implications for the GNAT System

    NASA Astrophysics Data System (ADS)

    Tucker, R. A.

    2002-12-01

    The Global Network of Astronomical Telescopes is developing a geographically distributed network of relatively small-aperture imaging telescopes. Equipped with CCD cameras and operating in scan mode, these instruments will be able to address a wide variety of solar system, stellar and extragalactic research topics. Although the design of the individual telescope emphasizes simplicity and low cost, the network will be able to deliver in aggregate data that would otherwise require more expensive facilities. The array of instruments may be tailored to the particular observing program by the selection of filters the individual instruments are provided and how the telescopes are pointed at the sky. A prototype array of three instruments has been in use since April of 2001, principally obtaining asteroid astrometry and searching for near-earth objects. The experience relating to solar system observations acquired during this period will be presented along with proposed strategies for future work using the full GNAT array of instruments. This work and continuing operation of the MOTESS prototype is supported in part by a Eugene Shoemaker Grant from The Planetary Society.

  11. The University of Illinois radio telescope

    Microsoft Academic Search

    Y. Lo

    1961-01-01

    The University of Illinois radio telescope is a reflector in the shape of a parabolic cylinder whose aperture is400 feet times 600feet. A 425-foot-long phase-adjustable array of receiving antennas lies along the focal line and produces a pencil beam one-third degree in width, steerable in the meridian plane up to 30 degrees in either direction from the zenith. The array

  12. Optimization of 100-meter Green Bank Telescope

    NASA Technical Reports Server (NTRS)

    Strain, Douglas

    1994-01-01

    Candidate designs for NRAO's 100-m clear-aperture radio telescope were evaluated and optimized by JPL using JPL-developed structural optimization and analysis software. The weight of a non-optimum design was reduced from 9.4 million pounds to 9.2 million pounds. The half-pathlength error due to gravity deformations was reduced from 0.041-inch rms to 0.034-inch rms.

  13. High resolution telescope including an array of elemental telescopes aligned along a common axis and supported on a space frame with a pivot at its geometric center

    DOEpatents

    Norbert, M.A.; Yale, O.

    1992-04-28

    A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employes speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by a electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes. 15 figs.

  14. High resolution telescope including an array of elemental telescopes aligned along a common axis and supported on a space frame with a pivot at its geometric center

    DOEpatents

    Norbert, Massie A. (San Ramon, CA); Yale, Oster (Danville, CA)

    1992-01-01

    A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employes speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by a electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.

  15. Extra-solar astronomy with a 2.4 m normal incidence X-ray telescope at 0.1 arcsec resolution

    NASA Technical Reports Server (NTRS)

    Elvis, M.

    1982-01-01

    The advantages and disadvantages for astrophysical observations of a normal incidence X-ray telescope are considered. The baseline configuration is for a 2.4 meter diameter mirror operating at 0.23-0.28 keV with a CCD detector having a pixel size equivalent to 0.1 arcsec. This resolution enables X-ray images to be made comparable to those of Space Telescope in the optical and to those of the Very Large Array in the radio for a large number of sources. Specific examples cover essentially the entire range of astrophysics.

  16. Image quality assessment of sparse-aperture designs with decreasing fill factors

    NASA Astrophysics Data System (ADS)

    Fiete, Robert D.; Mooney, James A.; Tantalo, Theodore A.; Calus, Jason R.

    2000-10-01

    Sparse aperture designs can increase the effective aperture size of a remote sensing system, thus allowing the satellite to be placed in a higher orbit without compromising the resolution. The fill factor of a sparse aperture is the total area of the telescope apertures divided by the effective aperture size of the combined telescopes. Reducing the fill factor, F, reduces the overall weight, but also reduces both the signal and the MTF (modulation transfer function). Increasing the effective integration time, t, and applying Wiener filters can gain back some of the lost image quality. This study generated image simulations of various sparse aperture designs to assess the image quality as a function of fill factor. This study found that the integration time needs to be increased by a factor of 1/F2 - 1/F3 in order to maintain the image quality as the fill factor decreased. This study also found that the GIQE (Generalized Image Quality Equation) did not accurately predict the change in image quality, in (Delta) NIIRS, as the fill factor is reduced.

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

    Microsoft Academic Search

    M. Hart; S. Esposito; S. Rabien

    2010-01-01

    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

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

    Microsoft Academic Search

    Lynn G. Seppala

    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

  19. Comparison of reconstruction algorithms for images from sparse-aperture systems

    NASA Astrophysics Data System (ADS)

    Fienup, James R.; Griffith, Douglas K.; Harrington, L.; Kowalczyk, A. M.; Miller, Jason J.; Mooney, James A.

    2002-12-01

    Telescopes and imaging interferometers with sparsely filled apertures can be lighter weight and less expensive than conventional filled-aperture telescopes. However, their greatly reduced MTF's cause significant blurring and loss of contrast in the collected imagery. Image reconstruction algorithms can correct the blurring completely when the signal-to-noise (SNR) is high, but only partially when the SNR is low. This paper compares both linear (Wiener) and nonlinear (iterative maximum likelihood) algorithms for image reconstruction under a variety of circumstances. These include high and low SNR, Gaussian noise and Poisson-noise dominated, and a variety of aperture configurations and degrees of sparsity. The quality metric employed to compare algorithms is image utility as quantified by the National Imagery Interpretability Rating Scale (NIIRS). On balance, a linear reconstruction algorithm with a power-law power-spectrum estimate performed best.

  20. High Contrast Science Program for the Exo-C Space Telescope Mission

    NASA Astrophysics Data System (ADS)

    Stapelfeldt, Karl R.; Marley, Mark S.; Bryden, Geoffrey; Meadows, Victoria; Belikov, Ruslan; McElwain, Michael W.; Exo-C Science; Technology Definition Team

    2015-01-01

    Exo-C is a detailed study of the science capability, engineering design, technology requirements, and costing for a modest-aperture space telescope with an internal coronagraph that could directly image exoplanetary systems. During its three year mission, Exo-C will carry out imaging and spectroscopy over the wavelength range 0.45-1.0 um towards the following goals: 1) Characterize the atmospheres of at least a dozen known, nearby radial velocity planets. Exo-C spectra will diagnose their atmospheric composition and the presence of clouds, performing the first such measurements of cool giant exoplanets like those in our own solar system. 2) Conduct an imaging survey of at least 100 additional nearby stars down to ~3e-10 contrast, enabling the discovery of new exoplanets down to super-Earth sizes. Sub-Neptune and super-Earth planets are relatively common in the exoplanet population, but have no counterparts in our Solar System. Exo-C spectra will provide the first atmospheric characterization for these intriguing objects. 3) Image several hundred circumstellar disks, revealing structures induced by planetary perturbations and the time evolution of disk properties. If exozodi is low and a very stable telescope can be achieved, habitable zone planets down to Earth size might be detected in a small sample of nearby stars including the alpha Cen system. Science targets, observing protocols, and future work will be discussed.

  1. Metamaterial Apertures for Computational Imaging

    NASA Astrophysics Data System (ADS)

    Hunt, John; Driscoll, Tom; Mrozack, Alex; Lipworth, Guy; Reynolds, Matthew; Brady, David; Smith, David R.

    2013-01-01

    By leveraging metamaterials and compressive imaging, a low-profile aperture capable of microwave imaging without lenses, moving parts, or phase shifters is demonstrated. This designer aperture allows image compression to be performed on the physical hardware layer rather than in the postprocessing stage, thus averting the detector, storage, and transmission costs associated with full diffraction-limited sampling of a scene. A guided-wave metamaterial aperture is used to perform compressive image reconstruction at 10 frames per second of two-dimensional (range and angle) sparse still and video scenes at K-band (18 to 26 gigahertz) frequencies, using frequency diversity to avoid mechanical scanning. Image acquisition is accomplished with a 40:1 compression ratio.

  2. Aperture impedance of flared horns

    NASA Technical Reports Server (NTRS)

    Silvestro, J. W.; Collin, R. E.

    1989-01-01

    The method of moments is often used when solving for the mutual coupling in arrays of aperture antennas. For elements that are waveguides or gradually flared horns the aperture fields can be approximated by a finite sum of waveguide modal functions. To solve for the flared horn case an approximation for the aperture impedances of the modes in the horn is needed. The WKB approach can be used to find these impedances, but this technique has an important limitation. It is known to fail in the vicinity of its turning points. The turning point is the cutoff point of the mode being considered. To overcome this limitation a different technique, the spherical mode approach, is discussed. This approach has no cutoff problems and works well for conical and pyramidal horns. Comparisons between the impedances and the resulting dominant mode reflection coefficient found using the two techniques are presented to illustrate this point.

  3. Wide-field Fizeau imaging telescope: experimental results.

    PubMed

    Kendrick, R L; Aubrun, Jean-Noel; Bell, Ray; Benson, Robert; Benson, Larry; Brace, David; Breakwell, John; Burriesci, Larry; Byler, Eric; Camp, John; Cross, Gene; Cuneo, Peter; Dean, Peter; Digumerthi, Ramji; Duncan, Alan; Farley, John; Green, Andy; Hamilton, Howard H; Herman, Bruce; Lauraitis, Kris; de Leon, Erich; Lorell, Kenneth; Martin, Rob; Matosian, Ken; Muench, Tom; Ni, Mel; Palmer, Alice; Roseman, Dennis; Russell, Sheldon; Schweiger, Paul; Sigler, Rob; Smith, John; Stone, Richard; Stubbs, David; Swietek, Gregg; Thatcher, John; Tischhauser, C; Wong, Harvey; Zarifis, Vassilis; Gleichman, Kurt; Paxman, Rick

    2006-06-20

    A nine-aperture, wide-field Fizeau imaging telescope has been built at the Lockheed-Martin Advanced Technology Center. The telescope consists of nine, 125 mm diameter collector telescopes coherently phased and combined to form a diffraction-limited image with a resolution that is consistent with the 610 mm diameter of the telescope. The phased field of view of the array is 1 murad. The measured rms wavefront error is 0.08 waves rms at 635 nm. The telescope is actively controlled to correct for tilt and phasing errors. The control sensing technique is the method known as phase diversity, which extracts wavefront information from a pair of focused and defocused images. The optical design of the telescope and typical performance results are described. PMID:16778931

  4. 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 order, this report simply summarizes the material with the various UAH-written presentation packages attached as appendices.

  5. Optical performance verification of the James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Barto, Allison A.; Atkinson, Charlie; Contreras, James; Lightsey, Paul A.; Noecker, Charley; Waldman, Mark; Whitman, Tony

    2008-07-01

    The James Webb Space Telescope (JWST) is a large aperture (6.6 m primary mirror) cryogenic telescope with active control of the segmented primary and secondary mirror optical elements. The architecture of the telescope makes full end-to-end testing on the ground prohibitive due to both cost and technical considerations. Additionally, because the telescope will be launched in a folded configuration to fit in the Ariane V launch fairing and aligned during flight using image-based Wavefront Sensing and Control (WFS&C), the telescope cannot be tested in the classical "test-as-you-fly" architecture. Due to these considerations, the primary optical performance requirements will be verified through analysis. In order to have high confidence in this approach, a robust analysis validation program has been developed based on testing from the component level through the integrated telescope level. This verification approach focuses on ground testing at the telescope level to ensure there will be adequate range in the adjustable optics for alignment on orbit. In addition to the incremental test program planned for optical verification, a double-pass sampled aperture test of the integrated telescope and instruments is planned at flight-like temperatures as a crosscheck to the analytic verification for flight. Error budgets have been developed to understand the uncertainty propagation through the test and analysis program.

  6. Automatization Project for the Carl-Zeiss-Jena Coudč Telescope of the Simón Bolívar Planetarium I. The Electro-Mechanic System

    NASA Astrophysics Data System (ADS)

    Núńez, A.; Maharaj, A.; Muńoz, A. G.

    2009-05-01

    The ``Complejo Científico, Cultural y Turístico Simón Bolívar'' (CCCTSB), located in Maracaibo, Venezuela, lodges the Simón Bolívar Planetarium and an 150 mm aperture, 2250 mm focal length Carl-Zeiss-Jena Coudč refractor telescope. In this work we discuss the schematics for the automatization project of this Telescope, the planned improvements, methodology, engines, micro-controllers, interfaces and the uptodate status of the project. This project is working on the first two levels of the automation pyramid, the sensor -- actuator level and the control or Plant floor level. The Process control level correspond to the software related section. This mean that this project work immediately with the electrical, electronic and mechanical stuffs, and with the assembler micro controller language. All the pc related stuff, like GUI (Graphic user interfaces), remote control, Grid database, and others, correspond to the next two automation pyramid levels. The idea is that little human intervention will be required to manipulate the telescope, only giving a pair of coordinates to ubicate and follow an object on the sky. A set of three servomotors, coupling it with the telescope with a gear box, are going to manipulate right ascension, declination and focus movement. For the dome rotation, a three phase induction motor will be used. For dome aperture/closure it is suggested a DC motor powered with solar panels. All those actuators are controlled by a 8 bits micro-controller, which receive the coordinate imput, the signal from the position sensors and have the PID control algorithm. This algorithm is tuned based on the mathematical model of the telescope electro-mechanical instrumentation.

  7. Atmospheric phase fluctuation measurement: interferometric results from the WHT and COAST telescopes

    Microsoft Academic Search

    Christopher A. Haniff; John E. Baldwin; Peter J. Warner; Tania R. Scott

    1994-01-01

    We have used interferometric methods to track the atmospheric phase fluctuations at two astronomical sites: the Observatorio del Roque de los Muchachos in the Canary Islands, the site of the 4.2-m William Herschel Telescope (WHT), and the Lord's Bridge observatory in Cambridge, the location of the Cambridge Optical Aperture Synthesis Telescope (COAST). At both sites the atmospheric perturbations are well

  8. Visible interferometric coupling of two telescopes through single mode optical fibers

    Microsoft Academic Search

    S. R. Restaino; R. J. McBroom; J. Baker; R. A. Carreras; G. C. Loos

    1996-01-01

    The diameter of large conventional astronomical telescopes is currently restricted to the range of eight to ten meters. With this limitation in mind, there is an emerging interest in various applications of optical interferometry which would allow the synthesis of apertures larger than can be realized using current mirror fabrication technologies. Interferometry allows the substitution of the separation between telescopes

  9. An Evolvable Space Telescope for NASA’s Next UVOIR Flagship Mission

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    NASA has sponsored several studies to develop conceptual designs for the next UVOIR Flagship mission, including an Advanced Technology Large Space Telescope (ATLAST). These studies concluded that a space observatory launched in ~2030 will require a telescope aperture of 8 to 16 meters to address the most compelling astrophysical questions raised by missions such as HST, Kepler, TESS, JWST and WFIRST as well as the large ground based telescopes that will coming on-line in the next decade. This telescope will be designed to search for the bio-signatures of life in the universe as well as to study the physics of star formation and to unravel the complex interactions between dark matter, galaxies and the intergalactic medium.Unfortunately, telescopes with this aperture will have a long development time with peak funding requirements that will absorb most NASA's Astrophysics budget for many years. To minimize this impact on NASA's budget and to drastically shorten the time between program start and 'first light' for this UVOIR space observatory we have been developing conceptual designs for an Evolvable Space Telescope (EST) that would be assembled on-orbit in three stages, beginning with the launch of a 2 mirror 4 x 12 meter telescope with 2 instruments 5 to 7 years after program start, and then adding mirror segments and instruments ay ~ 5 year intervals to obtain a 12-m filled aperture, and then a 20-m filled aperture telescope. We describe our approach in this presentation.

  10. Neutrino telescopes

    SciTech Connect

    Costantini, H., E-mail: costant@cppm.in2p3.fr [CPPM, Aix-Marseille Universite, CNRS/IN2P3 (France)

    2012-09-15

    Neutrino astrophysics offers a new possibility to observe our Universe: high-energy neutrinos, produced by the most energetic phenomena in our Galaxy and in the Universe, carry complementary (if not exclusive) information about the cosmos: this young discipline extends in fact the conventional astronomy beyond the usual electromagnetic probe. The weak interaction of neutrinos with matter allows them to escape from the core of astrophysical objects and in this sense they represent a complementary messenger with respect to photons. However, their detection on Earth due to the small interaction cross section requires a large target mass. The aim of this article is to review the scientific motivations of the high-energy neutrino astrophysics, the detection principles together with the description of a running apparatus, the experiment ANTARES, the performance of this detector with some results, and the presentation of other neutrino telescope projects.

  11. Options for the ESO Very Large Telescope Primary Mirrors

    Microsoft Academic Search

    D. Enard; K. Mischung; M. Schneermann; R. Wilson

    1986-01-01

    The ESO-VLT is based on the combination of four 8 m telescopes so as to provide a 16 m equivalent aperture. Two main possibilities for the manufacture of the mirror blanks are considered: a zero expansion glass ceramic from Schott and a lightweight steel structure. Manufacturing possibilities for both options as well as European industrial potentialities for the optical figuring

  12. Grand Old Telescopes

    NASA Astrophysics Data System (ADS)

    Benningfield, Damond

    2002-03-01

    The article recounts the history and work of three grand old telescopes: the 200-inch Hale Telescope at Palomar Observatory, the 82-inch Struve Telescope at McDonald Observatory, and the 100-inch Hooker Telescope at Mount Wilson Observatory outside Los Angeles, California. All three telescopes are available for viewing through public galleries or guided tours.

  13. Grid-Observing: Creating a Global Network of Telescopes

    NASA Astrophysics Data System (ADS)

    Hessman, F. V.; Gelderman, R.; Naylor, T.; Pennypacker, C.; Steele, I.

    2004-12-01

    With the increasing switch from classical observing campaigns to service observations, the decreasing pressure on a large number of 1 - 2m telescopes, and the rapid growth in the number of robotic, autonomous telescopes, it has become possible to create a truly global network of telescopes - what we call ``Grid-Observing." Such a network would permit a variety of photometric and spectroscopic monitoring and temporal survey projects which cannot be performed either with current or proposed larger telescopes (e.g. LSST) or with individual telescopes operated by a single institution. Participating observatories can be ``paid" for the services they provide to the network by being able to extract an equivalent amount of time on other telescopes, scaled by aperture, spectral resolution, atmospheric conditions, and the costs of operation or willingness to provide such a service. An XML interface - Remote Telescope Markup Language - insures that communications within the network are simple and relatively easily adapted to existent observatory software and procedures. An eBay-like mechanism for the automatic scheduling of telescopes can provide the necessary flexibility needed to perform time-critical projects as well as insure that the participating institutions retain full control over their telescopes. We are planning on networking several robotic telescope in the near future and expect that many other robotic and non-robotic telescopes will follow.

  14. SEASAT Synthetic Aperture Radar Data

    NASA Technical Reports Server (NTRS)

    Henderson, F. M.

    1981-01-01

    The potential of radar imagery from space altitudes is discussed and the advantages of radar over passive sensor systems are outlined. Specific reference is made to the SEASAT synthetic aperture radar. Possible applications include oil spill monitoring, snow and ice reconnaissance, mineral exploration, and monitoring phenomena in the urban environment.

  15. Wide Field Infrared Survey Telescope [WFIRST]: Telescope Design and Simulated Performance

    NASA Technical Reports Server (NTRS)

    Goullioud, R.; Content, D. A.; Kuan, G. M.; Moore, J. D.; Chang, Z.; Sunada, E. T.; Villalvazo, J.; Hawk, J. P.; Armani, N. V.; Johnson, E. L.; Powell, C. A.

    2012-01-01

    The ASTRO2010 Decadal Survey proposed multiple missions with NIR focal planes and 3 mirror wide field telescopes in the 1.5m aperture range. None of them would have won as standalone missions WFIRST is a combination of these missions, created by Astro 2010 committee. WFIRST Science Definition Team (SDT) tasked to examine the design. Project team is a GSFC-JPL-Caltech collaboration. This interim mission design is a result of combined work by the project team with the SDT.

  16. Detection of Callisto's oxygen atmosphere with the Hubble Space Telescope

    NASA Astrophysics Data System (ADS)

    Cunningham, Nathaniel J.; Spencer, John R.; Feldman, Paul D.; Strobel, Darrell F.; France, Kevin; Osterman, Steven N.

    2015-07-01

    We report the result of a search for evidence of an O2-dominated atmosphere on Callisto, using the high far-ultraviolet sensitivity of the Hubble Space Telescope Cosmic Origins Spectrograph (COS). Observations of Callisto's leading/Jupiter-facing hemisphere show, for the first time, variable-strength atomic oxygen (O I) emissions with brightness up to 4.7 ± 0.7 Rayleighs for the O I 1304 Ĺ triplet and 1.9 ± 0.4 Rayleighs for the O I 1356 Ĺ doublet, averaged over the 2.5 arcsec. diameter COS aperture. Because the observations were made in Earth's shadow, and are brighter than expected emission from nighttime geocoronal airglow or other plausible sources, we are confident that they originate from Callisto or its immediate vicinity. In addition, COS's limited (?1 arcsec) spatial resolution implies a 2? detection of excess 1356 Ĺ emission concentrated on the disk of Callisto itself, with brightness 3.2 ± 1.6 Rayleighs. The (O I 1356 Ĺ)/(O I 1304 Ĺ) emission ratio from Callisto's disk favors dissociative excitation of O2, suggesting that O2 is the dominant atmospheric component rather than other possible oxygen-bearing alternatives. Photoelectrons, rather than magnetospheric electrons, are the most likely source of the dissociative excitation. This detection yields an O2 column density of ?4 × 1015 cm-2 on the leading/Jupiter facing hemisphere, which implies that Callisto's atmosphere is collisional and is the fourth-densest satellite atmosphere in the Solar System, in addition to being the second-densest O2-rich collisional atmosphere in the Solar System, after Earth. Longitudinal variations in published densities of ionospheric electrons suggest that O2 densities in Callisto's trailing hemisphere, which we did not observe, may be an order of magnitude greater. The aperture-filling emissions imply that there is also an extended corona of predominantly O I 1304 Ĺ emission around Callisto, with observed strength of 1-4 Rayleighs, likely due to solar resonance scattering from sputtered atomic O, with a density of up to 104 cm-3 at the exobase.

  17. Solar Observations

    NSDL National Science Digital Library

    This is an activity involving observations of the Sun. Learners use pinhole cameras, solar telescopes, and/or solar viewing glasses to make solar observations, draw what they see, and identify sunspots, if they are present. Then, learners go online and compare their drawings to images obtained by the SOHO spacecraft. This activity requires the use a sunny outdoor location. This activity also require use of safe methods for observing the Sun, such as pinhole cameras, telescopes with proper solar filters attached, and/or viewing glasses that are designated for safe solar viewing. No one should look at the Sun unless one or more of these methods is used in a proper fashion.

  18. REVIEW ARTICLE Interferometric Synthetic Aperture Radar

    E-print Network

    Kansas, University of

    REVIEW ARTICLE Interferometric Synthetic Aperture Radar Christopher T. Allen Department of Electrical Engineering and Computer Science and Radar Systems and Remote Sensing Laboratory University of Kansas Abstract. This paper provides a brief review of interferometric synthetic aperture radar (In

  19. Fresnel diffraction of aperture with rough edge

    NASA Astrophysics Data System (ADS)

    Cui, Yuwei; Zhang, Wei; Wang, Junhong; Zhang, Meina; Teng, Shuyun

    2015-06-01

    The Fresnel diffraction of an aperture with a rough edge is studied in this paper. Circular and elliptical apertures with sinusoidal and random edges are chosen as examples to investigate the influence of the aperture edge on the diffraction. The numerical calculation results indicate intuitively the variations of the transverse and longitude diffraction intensity distributions with the edge parameters of the aperture. The data files of aperture models are obtained through the numerical calculations, and the aperture samples are obtained with the help of a liquid crystal light modulator (LCLM). Thus, the practical experiments of the diffractions of apertures with rough edges are carried out. The measured results are consistent with the calculated ones. The approximate analytic expressions of the diffraction by the modified aperture are deduced on the basis of the Fresnel diffraction theory and the statistic optics, and the reasonable explanations for the influence of edge parameters on the diffraction are given through the theoretical analysis.

  20. Preliminary Multi-Variable Cost Model for Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Hendrichs, Todd

    2010-01-01

    Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. This paper reviews the methodology used to develop space telescope cost models; summarizes recently published single variable models; and presents preliminary results for two and three variable cost models. Some of the findings are that increasing mass reduces cost; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and technology development as a function of time reduces cost at the rate of 50% per 17 years.

  1. Space infrared telescope facility project

    NASA Technical Reports Server (NTRS)

    Cruikshank, Dale P.

    1988-01-01

    The functions undertaken during this reporting period were: to inform the planetary science community of the progress and status of the Space Infrared Telescope Facility (SIRTF) Project; to solicit input from the planetary science community on needs and requirements of planetary science in the use of SIRTF at such time that it becomes an operational facility; and a white paper was prepared on the use of the SIRTF for solar system studies.

  2. Modern radioastronomical aperture synthesis systems (review)

    Microsoft Academic Search

    N. M. Tseytlin

    1984-01-01

    Although sequential aperture synthesis is based on an analogy to synthesis of antenna arrays it is not adequate for analysis of signals and radioluminance distributions which vary during movement of the antennas. Parallel aperture synthesis is performed by an interferometer with fixed antennas so that not only stationary processes but also transient ones can be simultaneously observed. The aperture synthesis

  3. Large sparse aperture space optical systems

    Microsoft Academic Search

    Aden B. Meinel; Marjorie P. Meinel

    2002-01-01

    The issue of how best to distribute a large optical collecting area is revisited, including the added integration time required for a scene imaged by sparse-aperture configurations to be processed to equal that of a filled aperture, and also its influence on system architecture. The optical performance of three sparse-aperture configurations arising from a 1998 study is presented as a

  4. Analysis of the Optical Design for the SAFIR Telescope

    NASA Technical Reports Server (NTRS)

    Goldsmith, Paul; Khayatian, Behrouz; Bradford, Matt; Dragovan, Mark; Hoppe, Daniel; Imbriale, William; Lee, Roger; Paine, Chris; Turner, Dick; Yorke, Harold; Zmuidzinas, Jonas

    2006-01-01

    SAFIR, the Single Aperture Far Infra Red Observatory, is a very powerful space mission that will achieve background-limited sensitivity in the far infrared-submillimeter spectral region. Many processes of enormous interest to astronomers can best be studied in this wavelength range, but require the demanding combination of high sensitivity, good angular resolution, and spectroscopic capability. SAFIR is a 10m class telescope to offering good angular resolution, cooled to below 5 K in order to achieve background-limited sensitivity, and equipped with a complement of large-format cameras and broadband spectrometers. Successful operation of such a facility is critically dependent on achieving the level of sensitivity expected, but this is rendered difficult by potential pickup from unwanted sources of radiation. This problem is exacerbated by the fact that the emission from the optical system itself is minimal due to its low temperature, thus emphasizing the importance of minimizing pickup from unwanted astronomical sources of radiation, including the emission from dust in our solar system (analogous to the zodiacal light, hence 'zodi'), and the emission from warm dust in the Milky Way (Galactic 'cirrus').

  5. Workshop on ESO's Very Large Telescope, Cargese, Corse, France, May 16-19, 1983, Proceedings

    NASA Astrophysics Data System (ADS)

    Swings, J.-P.; Kjaer, K.

    The present conference on the European Southern Observatory's planned Very Large Telescope (VLT) considers this instrument's potential for stellar astronomy, stellar chemistry, and interstellar matter and cosmological studies, as well as the optical detectors to be used in visible interferometry, IR spectroscopy, IR aperture synthesis, and high resolution imaging. Also discussed are the New Technology Telescope project predecessor to the VLT, novel large telescope configurations under consideration, site selection criteria for the VLT, and the testing of seeing quality and speckle siting.

  6. Science with 100-m telescopes

    NASA Astrophysics Data System (ADS)

    Gilmozzi, Roberto

    2000-06-01

    The next generation of ground based telescopes will break the 20th century paradigm of the 'factor of two' diameter increase. Taking advantage of the enormous advances in technology that the present generation of 8-10m telescopes has fostered, they will be fully adaptive, fully steerable behemoths of up to 100m diameter performing at the diffraction limit in the optical and near IR. At ten times the collecting area of every telescope ever built put together, they will have limiting magnitudes of 37-38, angular resolution of 1-2 milliarcseconds, and a price tag that does not follow the historical D2.6 cost law. In this paper we discuss some of the possible science cases for a telescope of 100m. Among them the determination of H unencumbered by local effects, the study of every SN ever exploded at any z < 10, the spectroscopy of extra-solar planets, studies of ultrahigh frequency phenomena, imaging of stellar surfaces, detection of brown dwarfs in external galaxies. The advent of the next generation of Extremely Large Telescopes will probably substantially change the operation all paradigm of astronomical observations, expanding on the present trend towards large programs, much in the way particle physics has gone with the large accelerators.

  7. Optical design study for NASA's spherical primary optical telescope (SPOT)

    NASA Astrophysics Data System (ADS)

    Howard, Joseph M.

    2004-10-01

    Several of NASA's future space telescopes project teams have chosen or are considering segmented primary mirrors as a part of their architecture. The James Webb Space Telescope (JWST) design employs a 6.5-meter conic primary mirror constructed of 18 hexagonal segments, where each hex is one of three off-axis surface profiles corresponding to its radial distance to the parent mirror axis. Other future mission concepts such as SAFIR (Single Aperture Far-Infra Red) and SUVO (Space Ultra Violet Optical telescope) are considering even larger segmented primary mirrors. The goal of the Spherical Primary Optical Telescope (SPOT) project discussed in this paper is to investigate the option of a spherical primary mirror for such future large aperture NASA missions. Ground-based telescopes such as the Hobby-Eberly have realized this design option, and the current baseline design for ESO's OWL project incorporates a 100-meter segmented spherical primary mirror. While the benefits of fabricating large numbers of identical spherical surface segments are obvious, the optical design for the telescope becomes more complex in order to correct the significant aberration resulting from a spherical primary surface. This paper briefly surveys design approaches of spherical primary telescopes. Image based performance comparisons are made, and examples are presented.

  8. Relay telescope for high power laser alignment system

    DOEpatents

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2006-09-19

    A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

  9. 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.

  10. New methods for masked-aperture and speckle interferometry

    E-print Network

    Timothy R. Bedding

    1999-01-18

    Diffraction-limited images can be obtained with a large optical telescope using interferometry. One such method for objects of sufficient brightness is non-redundant masking (NRM), in which observations are made through a pupil mask that contains an array of small holes. However, NRM only uses a small fraction of the available light. Here I describe a method for Extended NRM in which a cylindrical lens allows interferograms from many one-dimensional arrays to be recorded side-by-side on a two-dimensional detector. For fainter objects, the holes in the aperture mask should be replaced by slits. In this case, the mask can be removed entirely, with the cylindrical lens effectively creating a continuous series of one-dimensional interferograms. This modified form of speckle interferometry, which I call MODS (Multiplexed One-Dimensional Speckle), is intermediate between NRM and conventional full-aperture speckle. An existing speckle camera can easily be converted to MODS observations by inserting a cylindrical lens. The feasibility of both MODS and Extended NRM are demonstrated using observations with MAPPIT at the Anglo-Australian Telescope.

  11. Sparse Aperture Masking on Paranal

    NASA Astrophysics Data System (ADS)

    Lacour, S.; Tuthill, P.; Ireland, M.; Amico, P.; Girard, J.

    2011-12-01

    The new operational mode of aperture-masking interferometry was added to the CONICA camera four years ago. Over the years, the masks - pieces of metal only two centimetres wide - have opened an unprecedented observational window for the NACO instrument. In comparison to the full aperture, they deliver superior point source function calibration, rejection of atmospheric noise and robust recovery of phase information through the use of closure phases. In the resolution range from about half to several resolution elements, masking interferometry sets the benchmark for the present state of the art worldwide in delivering high fidelity imaging and direct detection of faint companions. The technique and observational applications to imaging of circumstellar discs and exoplanets are outlined.

  12. Controlled-aperture wave-equation migration

    SciTech Connect

    Huang, L. (Lian-Jie); Fehler, Michael C.; Sun, H. (Hongchuan); Li, Z. (Zhiming)

    2003-01-01

    We present a controlled-aperture wave-equation migration method that no1 only can reduce migration artiracts due to limited recording aperlurcs and determine image weights to balance the efl'ects of limited-aperture illumination, but also can improve thc migration accuracy by reducing the slowness perturbations within thc controlled migration regions. The method consists of two steps: migration aperture scan and controlled-aperture migration. Migration apertures for a sparse distribution of shots arc determined using wave-equation migration, and those for the other shots are obtained by interpolation. During the final controlled-aperture niigration step, we can select a reference slowness in c;ontrollecl regions of the slowness model to reduce slowncss perturbations, and consequently increase the accuracy of wave-equation migration inel hods that makc use of reference slownesses. In addition, the computation in the space domain during wavefield downward continuation is needed to be conducted only within the controlled apertures and therefore, the computational cost of controlled-aperture migration step (without including migration aperture scan) is less than the corresponding uncontrolled-aperture migration. Finally, we can use the efficient split-step Fourier approach for migration-aperture scan, then use other, more accurate though more expensive, wave-equation migration methods to perform thc final controlled-apertio.ee migration to produce the most accurate image.

  13. Design and validation of an air window for a molten salt solar thermal receiver

    E-print Network

    Paxson, Adam Taylor

    2009-01-01

    This thesis contributes to the development of Concentrating Solar Power (CSP) receivers and focuses on the design of an efficient aperture. An air window is proposed for use as the aperture of a CSP molten salt receiver ...

  14. STUDY OF RAPID FORMATION OF A {delta} SUNSPOT ASSOCIATED WITH THE 2012 JULY 2 C7.4 FLARE USING HIGH-RESOLUTION OBSERVATIONS OF THE NEW SOLAR TELESCOPE

    SciTech Connect

    Wang Haimin; Liu Chang; Wang Shuo; Deng Na; Xu Yan; Jing Ju [Space Weather Research Laboratory, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Cao Wenda, E-mail: haimin.wang@njit.edu [Big Bear Solar Observatory, New Jersey Institute of Technology, 40386 North Shore Lane, Big Bear City, CA 92314-9672 (United States)

    2013-09-10

    Rapid, irreversible changes of magnetic topology and sunspot structure associated with flares have been systematically observed in recent years. The most striking features include the increase of the horizontal field at the polarity inversion line (PIL) and the co-spatial penumbral darkening. A likely explanation of the above phenomenon is the back reaction to the coronal restructuring after eruptions: a coronal mass ejection carries the upward momentum while the downward momentum compresses the field lines near the PIL. Previous studies could only use low-resolution (above 1'') magnetograms and white-light images. Therefore, the changes are mostly observed for X-class flares. Taking advantage of the 0.''1 spatial resolution and 15 s temporal cadence of the New Solar Telescope at the Big Bear Solar Observatory, we report in detail the rapid formation of sunspot penumbra at the PIL associated with the C7.4 flare on 2012 July 2. It is unambiguously shown that the solar granulation pattern evolves to an alternating dark and bright fibril structure, the typical pattern of penumbra. Interestingly, the appearance of such a penumbra creates a new {delta} sunspot. The penumbral formation is also accompanied by the enhancement of the horizontal field observed using vector magnetograms from the Helioseismic and Magnetic Imager. We explain our observations as being due to the eruption of a flux rope following magnetic cancellation at the PIL. Subsequently, the re-closed arcade fields are pushed down toward the surface to form the new penumbra. NLFFF extrapolation clearly shows both the flux rope close to the surface and the overlying fields.

  15. Extra-Solar Planetary Imager (ESPI) for Space Based Jovian Planetary Detection

    NASA Technical Reports Server (NTRS)

    Lyon, Rick G.; Melnick, Gary J.; Nisenson, Peter; Papaliolios, Costa; Ridgeway, Steve; Friedman, Edward; Gezari, Dan Y.; Harwit, Martin; Graf, Paul

    2002-01-01

    We report on out Extra-Solar Planetary Imager (ESPI) study for a recent Midex (NASA Medium Class Explorer Mission) proposal. Proposed for ESPI was a 1.5 x 1.5 square meter Jacquinot apodized square aperture telescope. The combination of apodization and a square aperture telescope significantly reduces the diffracted light from a bright central source over much of the telescope focal plane. As a result, observations of very faint astronomical objects next to bright sources with angular separations as small as 0.32 arcseconds become possible. This permits a sensitive search for exo-planets in reflected light. The system is capable of detecting a Jupiter-like planet in a relatively long-period orbit around as many as 160 to 175 stars with a signal-to-noise ratio greater than 5 in observations lasting maximally 100 hours per star. We discuss the effects of wavefront error, mirror speckle, pointing error and signal-to-noise issues, as well as the scalability of our ESPI study with respect to NASA's Terrestrial Planet Finder mission.

  16. Observations and Modeling of Solar Coronal Structures Using High-Resolution Eclipse Images and Space-based Telescopes with Wide Field of View

    NASA Astrophysics Data System (ADS)

    Lu, Muzhou; Pasachoff, J. M.; Su, Y.; Van Ballegooijen, A. A.; Seaton, D. B.; West, M.

    2013-07-01

    We present a comparison of the solar corona observed during the total solar eclipses on 2010 July 11 and on 2012 November 13. The white light images were taken at Easter Island in 2010 and at Northeast Queensland, Australia, in 2012; while the concurrent EUV images were take with SDO/AIA and PROBA2/SWAP. The 2010 eclipse was observed at the beginning of Sunspot Cycle 24 [1], which peaked near our 2012 observation. We compare a plethora of corona features in the white light images and reveal some interesting differences in the enhanced EUV images taken by SDO/AIA and PROBA2/SWAP. We construct potential field models using our newly refined Coronal Modeling System (CMS2) software with line-of-sight photospheric magnetograms from SDO/HMI. The source surface heights derived from detailed comparison between our models and observations are compared to the standard source-surface model. We also compare the dynamics of the two eclipse observations. Similar to the 2010 eclipse, a CME was observed using temporally spaced eclipse images. We address unresolved problems in the models and observations with the hope of correcting them for future eclipse observations, such as the 2017 total solar eclipse across the continental U.S. References [1] Pasachoff, J. M., Rusin, V., Druckmüllerová, H., Saniga, M., Lu, M., Malamut, C., Seaton, D. B., Golub, L., Engell, A. J., Hill, S. W., Lucas, R., 2011, ApJ, 734, 114

  17. An imaging telescope for high energy gamma-ray astronomy

    NASA Technical Reports Server (NTRS)

    Frye, G.; Jenkins, T. L.; Owen, A.; Ramsden, D.; Carter, J. N.; Hall, C. J.

    1983-01-01

    Recent tests of a gamma-ray imaging telescope, which incorporated a coded aperture mask and multiwire proportional counter system produced good images of a tritium target source which was used to generate the 20 MeV protons at a proton Van de Graaff accelerator. This paper indicates what performance might be expected if a large area drift chamber were used in conjunction with a coded aperture mask. The prospects for achieving significant scientific results if such a system were flown on a variety of space vehicles are discussed.

  18. The Large Binocular Telescope: binocular all the time

    NASA Astrophysics Data System (ADS)

    Hill, J. M.; Ashby, D. S.; Brynnel, J. G.; Christou, J. C.; Little, John K.; Summers, D. M.; Veillet, C.; Wagner, R. M.

    2014-07-01

    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. Many science observations collect the light from the two sides separately. With the arrival of the second copy of the near-infrared spectrometer and the second copy of the optical spectrometer, the telescope is observing with both apertures a significant fraction of the time. The light from the two primary mirrors can be combined to produce phased-array imaging of an extended field. This coherent imaging along with adaptive optics gives the telescope the diffraction-limited resolution of a 22.65-meter telescope. Adaptive optics loops are routinely closed with natural stars on both sides of the telescope for combined beam observations. Twin laser guide star constellations have recently been installed for ground layer adaptive optics observations. Commissioning of new instruments and focal stations for high resolution spectroscopy and near-infrared phased-array imaging is underway.

  19. Polarization Compensation of Fresnel Aberrations in Telescopes

    NASA Technical Reports Server (NTRS)

    Clark, Natalie; Breckenridge, James B.

    2011-01-01

    Large aperture space telescopes are built with low F# s to accommodate the mechanical constraints of launch vehicles and to reduce resonance frequencies of the on-orbit system. Inherent with these low F# s is Fresnel polarization which affects image quality. We present the design and modeling of a nano-structure consisting of birefringent layers to control polarization and increase contrast. Analysis shows a device that functions across a 400nm bandwidth tunable from 300nm to 1200nm. This Fresnel compensator device has a cross leakage of less than 0.001 retardance.

  20. Interferometry in the Era of Very Large Telescopes

    NASA Technical Reports Server (NTRS)

    Barry, Richard K.

    2010-01-01

    Research in modern stellar interferometry has focused primarily on ground-based observatories, with very long baselines or large apertures, that have benefited from recent advances in fringe tracking, phase reconstruction, adaptive optics, guided optics, and modern detectors. As one example, a great deal of effort has been put into development of ground-based nulling interferometers. The nulling technique is the sparse aperture equivalent of conventional coronography used in filled aperture telescopes. In this mode the stellar light itself is suppressed by a destructive fringe, effectively enhancing the contrast of the circumstellar material located near the star. Nulling interferometry has helped to advance our understanding of the astrophysics of many distant objects by providing the spatial resolution necessary to localize the various faint emission sources near bright objects. We illustrate the current capabilities of this technique by describing the first scientific results from the Keck Interferometer Nuller that combines the light from the two largest optical telescopes in the world including new, unpublished measurements of exozodiacal dust disks. We discuss prospects in the near future for interferometry in general, the capabilities of secondary masking interferometry on very large telescopes, and of nulling interferometry using outriggers on very large telescopes. We discuss future development of a simplified space-borne NIR nulling architecture, the Fourier-Kelvin Stellar Interferometer, capable of detecting and characterizing an Earth twin in the near future and how such a mission would benefit from the optical wavelength coverage offered by large, ground-based instruments.

  1. Reconstruction of coded aperture images

    NASA Technical Reports Server (NTRS)

    Bielefeld, Michael J.; Yin, Lo I.

    1987-01-01

    Balanced correlation method and the Maximum Entropy Method (MEM) were implemented to reconstruct a laboratory X-ray source as imaged by a Uniformly Redundant Array (URA) system. Although the MEM method has advantages over the balanced correlation method, it is computationally time consuming because of the iterative nature of its solution. Massively Parallel Processing, with its parallel array structure is ideally suited for such computations. These preliminary results indicate that it is possible to use the MEM method in future coded-aperture experiments with the help of the MPP.

  2. the Large Aperture GRB Observatory

    SciTech Connect

    Bertou, Xavier [Centro Atomico Bariloche (Argentina)

    2009-04-30

    The Large Aperture GRB Observatory (LAGO) aims at the detection of high energy photons from Gamma Ray Bursts (GRB) using the single particle technique (SPT) in ground based water Cherenkov detectors (WCD). To reach a reasonable sensitivity, high altitude mountain sites have been selected in Mexico (Sierra Negra, 4550 m a.s.l.), Bolivia (Chacaltaya, 5300 m a.s.l.) and Venezuela (Merida, 4765 m a.s.l.). We report on the project progresses and the first operation at high altitude, search for bursts in 6 months of preliminary data, as well as search for signal at ground level when satellites report a burst.

  3. Synthetic aperture interferometry: error analysis.

    PubMed

    Biswas, Amiya; Coupland, Jeremy

    2010-07-10

    Synthetic aperture interferometry (SAI) is a novel way of testing aspherics and has a potential for in-process measurement of aspherics [Appl. Opt. 42, 701 (2003)]. A method to measure steep aspherics using the SAI technique has been previously reported [Appl. Opt. 47, 1705 (2008)]. Here we investigate the computation of surface form using the SAI technique in different configurations and discuss the computational errors. A two-pass measurement strategy is proposed to reduce the computational errors, and a detailed investigation is carried out to determine the effect of alignment errors on the measurement process. PMID:20648161

  4. Phase retrieval in sparse aperture systems with phase diversity: a trade space study

    NASA Astrophysics Data System (ADS)

    Daniel, Brian J.; Bolcar, Matthew R.; Schott, John R.; Fienup, James R.

    2008-04-01

    Sparse-aperture (SA) telescopes are a technology of interest in the field of remote sensing. Significant optical resolution can be achieved by an array of sub-apertures, mitigating size and weight limitations of full aperture space-deployed sensors. Much of the analysis to date has been done with the assumption that an extended scene is spectrally flat and each pixel has the same spectrum (gray-world assumption). Previous work has found the gray-world assumption is not valid when imaging a spectrally diverse scene and/or when the optical configuration is heavily aberrated. Broadband phase diversity (BPD) is an image-based method to detect the aberrations of a system. It also assumes a gray-world. Digital simulations that quantify the limitations of BPD with respect to spectral diversity of the extended scene, the RMS of the optical path difference (OPD), noise of the system, and band width of the sensor are presented.

  5. MULTI-STRANDED AND MULTI-THERMAL SOLAR CORONAL LOOPS: EVIDENCE FROM HINODE X-RAY TELESCOPE AND EUV IMAGING SPECTROMETER DATA

    SciTech Connect

    Schmelz, J. T.; Nasraoui, K. [Physics Department, University of Memphis, Memphis, TN 38152 (United States); Saar, S. H.; Kashyap, V. L.; Weber, M. A.; DeLuca, E. E.; Golub, L., E-mail: jschmelz@memphis.ed [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)

    2010-11-10

    Data from the X-Ray Telescope (XRT) and the EUV Imaging Spectrometer (EIS) on the Japanese/USA/UK Hinode spacecraft were used to investigate the spatial and thermal properties of an isolated quiescent coronal loop. We constructed differential emission measure (DEM) curves using Monte Carlo based, iterative forward fitting algorithms. We studied the loop as a whole, in segments, in transverse cuts, and point-by-point, always with some form of background subtraction, and find that the loop DEM is neither isothermal nor extremely broad, with approximately 96% of the EM between 6.2 {<=}log T{<=} 6.7, and an EM-weighted temperature of log T = 6.48 {+-} 0.16. We find evidence for a gradual change in temperature along the loop, with log T increasing only by {approx}0.1 from the footpoints to the peak. The combine XRT-EIS data set does a good job of constraining the temperature distribution for coronal loop plasma. Our studies show that the strong constraints at high and low temperatures provided by the combined data set are crucial for obtaining reasonable solutions. These results confirm that the observations of at least some loops are not consistent with isothermal plasma, and therefore cannot be modeled with a single flux tube and must be multi-stranded.

  6. Aperture Efficiencies of Impulse Radiating Antennas

    Microsoft Academic Search

    C. Jerald Buchenauer; J. Scott Tyo; Jon S. H. Schoenberg

    A concept of aperture efficiency is introduced for the purpose of comparing and optimizing the performance of impulse radiating\\u000a antennas (IRAs). The aperture efficiencies of popular lens and reflector IRAs are computed as the ratios of peak radiated\\u000a power densities on boresight compared with that produced by anideal IRA with an aperture of equal area and equal total input\\u000a power.

  7. Astrometric Detection of Extrasolar Planets: Results of a Feasibility Study with the Palomar 5 Meter Telescope

    NASA Technical Reports Server (NTRS)

    Pravdo, Steven H.; Shaklan, Stuart B.

    1996-01-01

    The detection of extrasolar planets around stars like the Sun remains an important goal of astronomy. We present results from Palomar 5 m observations of the open cluster NGC 2420 in which we measure some of the sources of noise that will be present in an astrometric search for extrasolar planets. This is the first time that such a large aperture has been used for high-precision astrometry. We find that the atmospheric noise is 150 micro-arcsec hr(exp 1/2) across a 90 sec field of view and that differential chromatic refraction (DCR) can be calibrated to 128 micro-arcsec for observations within 1 hr of the meridian and 45 deg of zenith. These results confirm that a model for astrometric measurements can be extrapolated to large apertures. We demonstrate, based upon these results, that a large telescope achieves the sensitivity required to perform a statistically significant search for extra solar planets. We describe an astrometric technique to detect planets, the astrometric signals expected, the role of reference stars, and the sources of measurement noise: photometric noise, atmospheric motion between stars, sky background, instrumental noise, and DCR. For the latter, we discuss a method to reduce the noise further to 66 micro-arcsecond for observations within 1 hr of the meridian and 45 deg of zenith. We discuss optimal lists of target stars taken from the latest Gliese & Jahreiss catalog of nearby stars with the largest potential astrometric signals, declination limits for both telescope accessibility and reduced DCR, and galactic latitude limits for a sufficiant number of reference stars. Two samples are described from which one can perform statistically significant searches for gas giant planets around nearby stars. One sample contains 100 "solar class" stars with an average stellar mass of 0.82 solar mass; the other maximizes the number of stars, 574, by searching mainly low-mass M stars. We perform Monte Carlo simulations of the statistical significance of the expected results by using measured and estimated noise quantities. We show the semimajor axis parameter spaces that are searched for each star and how an increase in the length of the observing program expands these spaces. The search over semimajor axis parameter space relates to the theory of gas giant planet formation.

  8. Lower Limits on Aperture Size for an ExoEarth-Detecting Coronagraphic Mission

    E-print Network

    Stark, Christopher C; Mandell, Avi; Clampin, Mark; Domagal-Goldman, Shawn D; McElwain, Michael W; Stapelfeldt, Karl R

    2015-01-01

    The yield of Earth-like planets will likely be a primary science metric for future space-based missions that will drive telescope aperture size. Maximizing the exoEarth candidate yield is therefore critical to minimizing the required aperture. Here we describe a method for exoEarth candidate yield maximization that simultaneously optimizes, for the first time, the targets chosen for observation, the number of visits to each target, the delay time between visits, and the exposure time of every observation. This code calculates both the detection time and multi-wavelength spectral characterization time required for planets. We also refine the astrophysical assumptions used as inputs to these calculations, relying on published estimates of planetary occurrence rates as well as theoretical and observational constraints on terrestrial planet sizes and classical habitable zones. Given these astrophysical assumptions, optimistic telescope and instrument assumptions, and our new completeness code that produces the hi...

  9. Autonomous tip/tilt alignment and phasing of a distributed aperture imaging testbed.

    PubMed

    Ni, Mel; Benson, Larry; Camp, John; Herman, Bruce

    2010-06-01

    Star-9 is an experimental demonstration of distributed aperture imaging built at the Lockheed Martin Advanced Technology Center. White light from a scene generator enters an array of nine actively controlled telescopes, and is combined at a focused image plane. This paper describes the algorithms used to automatically bring each telescope's relative tip/tilt and phasing errors to within the operational range of the control system. The algorithms work with point-sources as well as with extended scenes. Experimental results and software algorithms are presented. PMID:20588434

  10. Extracting spatial information from large aperture exposures of diffuse sources

    NASA Astrophysics Data System (ADS)

    Clarke, J. T.; Moos, H. W.

    The spatial properties of large aperture exposures of diffuse emission can be used both to investigate spatial variations in the emission and to filter out camera noise in exposures of weak emission sources. Spatial imaging can be accomplished both parallel and perpendicular to dispersion with a resolution of 5-6 arc sec, and a narrow median filter running perpendicular to dispersion across a diffuse image selectively filters out point source features, such as reseaux marks and fast particle hits. Spatial information derived from observations of solar system objects is presented.

  11. Negative transconductance in apertured electron guns

    NASA Astrophysics Data System (ADS)

    Harris, John R.; O'Shea, Patrick G.

    2008-06-01

    Passing an electron beam through an aperture can serve to reduce the beam current or change the transverse beam profile. For a sufficiently intense beam, space charge will drive a radial expansion of the beam, which may cause the current passing through the aperture to decrease even though the current arriving at the aperture is increasing. When a gridded electron gun is used, this may be expressed by stating that the transconductance of the apertured gun is negative. Here, we explain this effect and explore some of the key factors governing when it can occur and influencing its strength.

  12. Negative Transconductance in Apertured Electron Guns

    SciTech Connect

    Harris, J R; O'Shea, P G

    2007-09-21

    Passing an electron beam through an aperture can serve to reduce the beam current or change the transverse beam profile. For a sufficiently intense beam, space charge will drive a radial expansion of the beam, which may cause the current passing through the aperture to increase even though the current arriving at the aperture is decreasing. When a gridded electron gun is used, this may be expressed by stating that the transconductance of the apertured gun is negative. Here we explain this effect, and explore some of the key factors governing when it can occur and influencing its strength.

  13. Ion mobility spectrometer with virtual aperture grid

    DOEpatents

    Pfeifer, Kent B. (Los Lunas, NM); Rumpf, Arthur N. (Albuquerque, NM)

    2010-11-23

    An ion mobility spectrometer does not require a physical aperture grid to prevent premature ion detector response. The last electrodes adjacent to the ion collector (typically the last four or five) have an electrode pitch that is less than the width of the ion swarm and each of the adjacent electrodes is connected to a source of free charge, thereby providing a virtual aperture grid at the end of the drift region that shields the ion collector from the mirror current of the approaching ion swarm. The virtual aperture grid is less complex in assembly and function and is less sensitive to vibrations than the physical aperture grid.

  14. Finite-aperture wire grid polarizers.

    PubMed

    Jensen, M A; Nordin, G P

    2000-12-01

    The transmission characteristics of wire grid polarizers fabricated in finite apertures are investigated by using a three-dimensional finite-difference time-domain formulation. Specifically, the optical transmissivity and extinction ratio are characterized for a wide variety of geometrical parameters including aperture size in both dimensions, conducting wire fill factor, and polarizer thickness. A dispersive material model is used to investigate the performance of polarizers fabricated by using realistic metals at infrared wavelengths. The results indicate that the aperture dimension significantly impacts the polarizer transmission behavior and that the extinction of the unwanted polarization is often limited by depolarizing scattering that is due to the finite aperture size. PMID:11140477

  15. Integrated control system development for phasing and vibration suppression for a sparse-array telescope

    Microsoft Academic Search

    Karl N. Schrader; Rob H. Fetner; Jed Donaldson; Robert J. Fuentes; Richard S. Erwin

    2002-01-01

    This paper presents the development of the control system architecture for vibration mitigation and autonomous phasing of sub-apertures on a sparse-array test bed. The paper begins with a brief description of the telescope system under consideration, including the actuation system providing 3 degree-of-freedom rigid body correction to each sub-aperture, and the metrology system, comprised of a white-light-based low-bandwidth absolute position

  16. Overview of the James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Clampin, Mark

    The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 µm to 28 µm. JWST's primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation and protoplanetary systems, and formation of evolution of planetary systems. We will review JWST's science goals and discuss recent progress in the design of JWST's observatory architecture following the completion of a key milestone, the Mission Preliminary Design Review (PDR). In particular we will discuss the status of JWST's optical system, progress in the primary mirror fabrication program, and the status of key observatory elements such as the sunshield. We will also address the current projected scientific performance of the observatory in the context of its science goals.

  17. Status of The James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Clampin, Mark

    2009-01-01

    The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 ?m to 28 ?m. JWST's primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, and the formation of evolution of planetary systems. We will present an overview of the Observatory's current design following the Mission Preliminary Design Review, (PDR). Recent progress in hardware development for the observatory will be presented, including a discussion of the status of JWST's optical system and Beryllium mirror fabrication, progress with sunshield prototypes, and recent changes in the integration and test configuration. We also review the expected scientific performance of the observatory based on the mission PDR design.

  18. Hubble Space Telescope particulate optical test

    NASA Astrophysics Data System (ADS)

    Metheny, Wayne; Pope, Tom; Rosenberg, William; Sharbaugh, Ron

    1987-01-01

    The Particulate Optical Test was designed to record and measure particulate contaminants on the Hubble Space Telescope primary mirror. The objective of the test was to quantify the primary mirror particulate contamination prior to launch. The test consists of taking dark-field photographs of the primary mirror from in front of the telescope's aperture door. These photographs are subsequently digitized and analyzed to produce the areal coverage estimates. The estimated particulate areal obscuration is approximately 1.0 percent of the primary mirror surface in the usable region. This level of contamination is within the budget value of 2.5 percent and indicates that there was little increase in particulate contamination during the HST assembly process or the acoustic test period.

  19. 5cm aperture dipole studies

    SciTech Connect

    McInturff, A.D.; Bossert, R.; Carson, J.; Fisk, H.E.; Hanft, R.; Kuchnir, M.; Lundy, R.; Mantech, P.; Strait, J.

    1986-09-30

    The results obtained during the evolution of the design, construction, and testing program of the design ''B'' dipole are presented here. Design ''B'' is one of the original three competing designs for the Superconducting Super Collider ''SSC'' arc dipoles. The final design parameters were as follows: air cored (less than a few percent of the magnetic field derived from any iron present), aluminum collared, two layered winding, 5.5T maximum operating field, and a 5 cm cold aperture. There have been fourteen 64 cm long 5 cm aperture model dipoles cold tested (at 4.3K and less) in this program so far. There was a half length full size (6m) mechanical analog (M-10) built and tested to check the cryostat's mechanical design under ramping and quench conditions. Several deviations from the ''Tevatron'' dipole fabrication technique were incorporated, for example the use of aluminum collars instead of stainless steel. The winding technique variations explored were ''dry welding,'' a technique with the cable covered with Kapton insulation only and ''wet winding'' where the Kapton was covered with a light coat of ''B'' stage epoxy. Test data include quench currents, field quality (Fourier multipole co-efficients), coil magnetization, conductor current performance, and coil loading. Quench current, loss per cycle, and harmonics were measured as a function of the magnitude and rate of change of the magnetic field, and helium bath temperature.

  20. Wide band dual circularly polarized aperture coupled microstrip patch antenna with bow tie shaped apertures

    Microsoft Academic Search

    A. K. Sharma; R. Singh; A. Mittal

    2004-01-01

    A wide band aperture coupled microstrip antenna with dual circular polarization operation is proposed. The antenna is designed and simulated to enable the transmission and reception of different circularly polarized wide band signals simultaneously with a single antenna. Instead of conventional rectangular apertures, two orthogonally placed bow-tie shaped apertures fed by a 3 dB branch line coupler are used to

  1. The SOHO Extreme Ultraviolet Imaging Telescope

    NSDL National Science Digital Library

    Users can access a variety of information about the The SOHO Extreme Ultraviolet Imaging Telescope, as well as maps, imagery, and data. A description of the instrument is provided, along with temperature maps, movies and images of eclipses, solar storms, and coronal mass ejections. Links to related sites are also included.

  2. Telescopes from Afar

    NASA Astrophysics Data System (ADS)

    Genet, Russell M.

    2011-05-01

    Fully robotic telescopes at the Fairborn Observatory, which began operation in 1983, have been in continuous operation for a quarter century. Although initially confined to smaller telescopes, automation and remote access have now spread to the largest telescopes. Due to the high cost of transportation, many large telescopes, such as Keck, are now being operated remotely by astronomers in real time. Others, such as the Canada-France- Hawaii telescope, are being operated autonomously without any onsite staff. A recent conference, Telescopes from Afar, allowed a contrast to be made between early automation and remote access developments at the Fairborn Observatory and the current state-of-the-art in these areas for both small and large telescopes, as well as consideration of a recent development-networks of small automated telescopes.

  3. SOPHOS -- SOuth Pole High-altitude ObServatory: Aperture Configuration and Imaging Performance

    NASA Astrophysics Data System (ADS)

    Burrows, C.; White, R. L.; Bely, P.; Ford, H.

    1993-12-01

    SOPHOS is an aerostat-borne, sparsely filled 6-meter optical telescope that we plan to fly in Antartica. This paper presents the results of studies concerning the aperture configuration and the results of simulations of the imaging performance of the telescope. We first describe the results of a computer optimization of the subapertures following a method proposed by T. Cornwell, which consists of optimizing the coverage of the Fourier plane. When taking advantage of the earth's rotation (by taking exposures with the overall aperture rotated around the line of sight), the optimum configuration of subapertures is on a circle with unequal spacing. The effects of the spacing and diameter of the individual mirrors on the optical performance will be presented. We then present the results of simulations in retrieving the observed object. When an object is observed at several roll angles, the point spread function is simply rotated at each roll angle and hence needs to be measured only once; it can be resampled for each observation. The images can be deconvolved using the Richardson-Lucy method, and it is possible to improve the images by deconvolving a set of images taken at different rolls using a single deconvoled image and a single (rotated) PSF. We will present examples of simulated image data, reconstructions in the presence of background and readout noise, and comparisons with images obtained with a filled-aperture telescope. We will also show the effects of imperfect cophasing of the subapertures on image reconstruction.

  4. Experimental measurement and computer analysis of stray radiation in a telescope

    NASA Technical Reports Server (NTRS)

    Hunt, G. H.; Shelton, G. B.

    1977-01-01

    A description is presented of an experimental measurement system for the study of the stray radiation performance of a 50-cm aperture astronomical telescope model. The model incorporates a very high performance baffle system. To simulate the space environment of the actual orbiting telescope, the telescope model was placed in a vacuum chamber. The stray radiation source for the experiment was a ruby laser system. A photomultiplier tube was used for the detector. A minicomputer system was used to control the experiment and to gather and process the data. A computer program was used to model the telescope baffle system. Experimentally and analytically determined stray radiation attenuation data are compared.

  5. Global Telescope Network Website

    NSDL National Science Digital Library

    2005-06-14

    This Web site contains information for both partners (those with their own telescopes) and associates (those who wish to use a network telescope.) The purpose of the Global Telescope Network (GTN) is to use small telescopes to obtain ground-based observations of high-energy objects of interest to Swift, GLAST (renamed Fermi in 2008) and XMM-Newton missions. It is used both by formal educators working with students and by amateur astronomers.

  6. Shuttle infrared telescope facility (SIRTF) preliminary design study

    NASA Technical Reports Server (NTRS)

    1976-01-01

    An overall picture of the SIRTF system is first presented, including the telescope, focal plane instruments, cryogen supply, shuttle and spacelab support subsystems, mechanical and data interfaces with the vehicles, ground support equipment, and system requirements. The optical, mechanical, and thermal characteristics of the telescope are then evaluated, followed by a description of the SIRTF internal stabilization subsystem and its interface with the IPS. Expected performance in the shuttle environment is considered. Tradeoff studies are described, including the Gregorian versus the Cassegrain telescope, aperture diameter tradeoff, a CCD versus an image dissector for the star tracker, the large ambient telescope versus the SIRTF, and a dedicated gimbal versus the IPS. Operations from integration through launch and recovery are also discussed and cost estimates for the program are presented.

  7. The space telescope

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Papers concerning the development of the Space Telescope which were presented at the Twenty-first Annual Meeting of the American Astronautical Society in August, 1975 are included. Mission planning, telescope performance, optical detectors, mirror construction, pointing and control systems, data management, and maintenance of the telescope are discussed.

  8. The South Pole Telescope

    Microsoft Academic Search

    John Ruhl; Peter A. R. Ade; John E. Carlstrom; Hsiao-Mei Cho; Thomas Crawford; Matt Dobbs; Chris H. Greer; Nils w. Halverson; William L. Holzapfel; Trevor M. Lanting; Adrian T. Lee; Erik M. Leitch; Jon Leong; Wenyang Lu; Martin Lueker; Jared Mehl; Stephan S. Meyer; Joe J. Mohr; Steve Padin; T. Plagge; Clem Pryke; Marcus C. Runyan; Dan Schwan; M. K. Sharp; Helmuth Spieler; Zak Staniszewski; Antony A. Stark

    2004-01-01

    A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an

  9. Large Binocular Telescope Project

    Microsoft Academic Search

    John M. Hill; Piero Salinari

    1998-01-01

    The Large Binocular Telescope (LBT) Project is a collaboration between institutions in Arizona, Germany, Italy, and Ohio. With the addition of the partners from Ohio State and Germany in February 1997, the Large Binocular Telescope Corporation has the funding required to build the full telescope populated with both 8.4 meter optical trans. The first of two 8.4 meter borosilicate honeycomb

  10. Dr. Massimo Space Telescope

    E-print Network

    Zanibbi, Richard

    Dr. Massimo Robberto Space Telescope Science Institute Massimo Robberto received in 1989 his Ph/VLT telescopes. In 1995 he joined the Max Planck Institutein Heidelberg to lead the construction of a new IR camera for the UKIRT telescope in Mauna Kea, Hawaii. In 1999 he moved to the European Space Agency

  11. The MAGIC Telescope

    E-print Network

    Ciro Bigongiari

    2005-12-07

    MAGIC (Major Atmospheric Gamma Imaging Cherenkov telescope) is presently the largest ground-based gamma ray telescope. MAGIC has been taking data regularly since October 2004 at the Roque de los Muchachos Observatory on the island of La Palma. In this paper the MAGIC telescope status, its performances and some preliminary results on observed gamma ray sources are presented.

  12. 551IEEE TRANSACTIONSON GEOSCIENCE AND REMOTE SENSING, VOL. 31, NO. 3, MAY 1993 MAST: A Mass Spectrometer Telescope for

    E-print Network

    Goddard III, William A.

    Spectrometer Telescope for M4 D1 D2 D3 D4 D5 D6 - I , Studies of the Isotopic Composition of Solar, Anomalous. Mewaldt, R. S. Selesnick, E. C. Stone, and T. T. von Rosenvinge Abstract-The Mass SpectrometerTelescope SpectrometerTelescope (MAST) and the Proton Electron Telescope (PET; see [l]), were originally part of the Com

  13. THE DUTCH OPEN TELESCOPE R.J. RUTTEN, R.H. HAMMERSCHLAG AND F.M. BETTONVIL

    E-print Network

    Rutten, Rob

    THE DUTCH OPEN TELESCOPE R.J. RUTTEN, R.H. HAMMERSCHLAG AND F.M. BETTONVIL Sterrekundig Instituut, Postbus 80 000, NL­3508 TA, Utrecht Abstract. The Dutch Open Telescope is now being installed at La Palma: solar physics, telescope design, atmospheric turbulence 1. DOT history The Dutch Open Telescope (DOT

  14. New robotic telescopes by Halfmann-Teleskoptechnik GmbH and Tuparev Technologies Inc.

    NASA Astrophysics Data System (ADS)

    Bischoff, Karsten; Hessman, Frederic V.; Tuparev, Georg; Atanasova, Ekatarina; Pessev, Peter

    2008-07-01

    We will present aspects of the installation, commissioning, software development, and early operation of several new robotic telescopes: 1) the 1.2-m MONET/South telescope at Sutherland/ZA, the second Halfmann telescope for the MONET telescope network (the other telescope has been in operation at McDonald Observatory in Texas since early 2006); 2) a siderostat for a 0.5-m vacuum tower telescope for the new physics building of the Georg-August-Universitat Göttingen and 3) new developments for smaller (down to 0.5m) aperture telescopes. Special emphasis will be given to drive technology: using torque motors we adjust maximum slewing speeds of 10°/sec as standard. Although sufficient for most projects we are investigating even faster slewing speeds.

  15. First light with a carbon fiber reinforced polymer 0.4 meter telescope

    NASA Astrophysics Data System (ADS)

    Wilcox, Christopher C.; Santiago, Freddie; Jungwirth, Matthew E.; Martinez, Ty; Restaino, Sergio R.; Bagwell, Brett; Romeo, Robert

    2014-03-01

    For the passed several years, the Naval Research Laboratory (NRL) has been investigating the use of Carbon Fiber Reinforced Polymer (CFRP) material in the construction of a telescope assembly including the optical components. The NRL, Sandia National Laboratories (SNL), and Composite Mirror Applications, Inc. (CMA) have jointly assembled a prototype telescope and achieved "first light" images with a CFRP 0.4 m aperture telescope. CFRP offers several advantages over traditional materials such as creating structures that are lightweight and low coefficient of thermal expansion and conductivity. The telescope's primary and secondary mirrors are not made from glass, but CFRP, as well. The entire telescope weighs approximately 10 kg while a typical telescope of this size would weigh quite a bit more. We present the achievement of "first light" with this telescope demonstrating the imaging capabilities of this prototype and the optical surface quality of the mirrors with images taken during a day's quiescent periods.

  16. 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.

  17. The flight test of a grazing incidence relay optics telescope for solar X-ray astronomy utilizing a thinned, back-illuminated CCD detector

    NASA Astrophysics Data System (ADS)

    Moses, J. Daniel; Davis, John M.

    1988-01-01

    The new AS&E Ultrahigh Resolution Soft X-ray Solar Research Rocket Payload has been successfully flown twice on Black Brant IX Sounding Rockets from White Sands Missile Range. These flights, conducted on 15 August 1987 and 11 December 1987, provided the first test of the new payload which consists of 3.8X magnifying hyperboloid-hyperboloid grazing incidence relay optic used in conjunction with an existing Wolter-I primary mirror. An RCA SID 500 series CCD detector was utilized in a thinned, back-illuminated configuration for recording the images. The 5.4 m effective focal length of the compound optics system resulted in a plate scale of 1 arc second per pixel which is comparable to the inherent resolution of the primary mirror. These flights represent the first use in X-ray astronomy of either of these two new technologies. These observations are presented with comparison to laboratory measurements and theoretical expectations of the instrument performance.

  18. Holographic Optical Elements as Scanning Lidar Telescopes

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.

    2005-01-01

    We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. For example, rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed and tested transmission and reflection HOEs for use at the first three harmonic wavelengths of Nd:YAG lasers. The diffraction efficiency, diffraction angle, focal length, focal spot size and optical losses were measured for several HOEs and holographic gratings, and found to be suitable for use as lidar receiver telescopes, and in many cases could also serve as the final collimating and beam steering optic for the laser transmitter. Two lidar systems based on this technology have been designed, built, and successfully tested in atmospheric science applications. This technology will enable future spaceborne lidar missions by significantly lowering the size, weight, power requirement and cost of a large aperture, narrow field of view scanning telescope.

  19. HIRF penetration through apertures: FDTD versus measurements

    Microsoft Academic Search

    Stavros V. Georgakopoulos; Craig R. Birtcher; Constantine A. Balanis

    2001-01-01

    The penetration of high-intensity radiated fields (HIRF) into conducting enclosures via apertures is an EMI issue that is relevant to all aviation. The stories are numerous, of disrupted communications, disabled navigation equipment, etc., due to the effects of EM sources external to the aircraft. Here, the FDTD method is used to predict the shielding effectiveness of conducting enclosures with apertures,

  20. Aperture feed for a spherical reflector

    Microsoft Academic Search

    M. Burrows; L. Ricardi

    1967-01-01

    The problem of designing a feed system for illuminating a spherical reflector is examined. A method is proposed for specifying the required field distribution over the aperture of the feed system, and the primary illumination and gain resulting from this distribution are derived. The results indicate that a significantly smaller feed aperture can be employed than would be indicated by

  1. Electromagnetic Penetration Through Apertures in Conducting Surfaces

    Microsoft Academic Search

    Chalmers Butler; Yahya Rahmat-Samii; Raj Mittra

    1978-01-01

    In designing hardened systems, one must be able to characterize as well as quantitatively determine the penetration of EMP signals through apertures of general shapes in structures of varying conflgurations. In this paper a tutorial review of a number of methods for analyzing such aperture problems is presented with an emphasis on techniques. The discussion presented herein is reasonably self-contained

  2. Hubble Space Telescope Servicing begins.

    NASA Astrophysics Data System (ADS)

    1993-12-01

    The day's work began when astronauts Story Musgrave and Jeff Hoffman stepped out into the cargo bay at 9h41 pm CST, Saturday (4h41 am CET, Sunday). They immediately set to work replacing two gyroscope assemblies, known as the Rate Sensor Units, two associated electronics boxes, called Electronic Control Units, and eight electrical fuse plugs. The work was completed ahead of schedule, but the astronauts had trouble closing the doors of the compartment housing the gyros and took over an hour to get them shut. The astronauts also prepared equipment for the replacement of the solar arrays. "The feeling down here is one of great satisfaction for a tremendous job today" said spacecraft communicator Greg Harbaugh in mission control. "We are very proud of the work that you all did and we are very confident in the continued success of the mission. Everything is going great and tomorrow is going to be another great day". ESA astronaut Claude Nicollier played a vital role during the spacewalk moving the astronauts and their equipment around the cargo bay with the shuttle's robot arm. The Hubble Space Telescope servicing mission features more robot arm operations than any other shuttle flight. The telescope's left-hand solar array was rolled up successfully at 6h24 am CST (1h24 pm CET). The 11-tonne observatory was rotated 180 degrees on its turntable before commands were sent to retract the second array at 8h23 am CST (3h23 pm CET). The crew stopped the retraction when it appeared the system may have jammed. Mission control instructed the crew to jettison the array, a procedure that they have trained for. Tomorrow astronauts Kathy Thornton and Tom Akers will make a six-hour spacewalk to jettison the troublesome wing, store the other in the cargo bay, and install two new panels supplied by ESA. The second set of arrays feature thermal shields and a modified thermal compensation system to prevent the flexing that affected the first pair. The Hubble Space Telescope was plucked from orbit this Saturday by ESA astronaut Claude Nicollier, operating the shuttle's robot arm. The Swiss-born astronaut gripped the 11- tonne observatory with the shuttle's 15-metre long robot arm at 2h34 am CST (9h34 am CET) after a two-day chase through space as the two spacecraft flew over the South Pacific Ocean. "Endeavour has a firm handshake with Mr. Hubble's telescope" said mission commander Dick Covey. "It's quite a sight". About half an hour later Nicollier had the telescope berthed on a special turntable in the back of the Shuttle's cargo bay. Later he used the camera at the end of the arm to surveyed the telescope for any damage. As the shuttle approached the telescope the astronauts first reported that one of the twin solar arrays appeared to be bowed and twisted. ESA officials said the problem was caused by the failure in early 1992 of the tensioning system on one side of the right-hand array. The system is designed to allow the blanket-like array to expand and contract in orbit. That failure placed stress on one of the supporting bi-stem booms resulting in its bent condition. Endeavour's mission began Thursday 2 December and will end 13 December. A total of five spacewalks are planned to service the telescope.

  3. MACS, An Instrument and a Methodology for Simultaneous and Global Measurements of the Coronal Electron Temperature and the Solar Wind Velocity on the Solar Corona

    NASA Technical Reports Server (NTRS)

    Reginald, Nelson L.

    2000-01-01

    In Cram's theory for the formation of the K-coronal spectrum he observed the existence of temperature sensitive anti-nodes, which were separated by temperature insensitive nodes, at certain wave-lengths in the K-coronal spectrum. Cram also showed these properties were remarkably independent of altitude above the solar limb. In this thesis Cram's theory has been extended to incorporate the role of the solar wind in the formation of the K-corona, and we have identified both temperature and wind sensitive intensity ratios. The instrument, MACS, for Multi Aperture Coronal Spectrometer, a fiber optic based spectrograph, was designed for global and simultaneous measurements of the thermal electron temperature and the solar wind velocity in the solar corona. The first ever experiment of this nature was conducted in conjunction with the total solar eclipse of 11 August 1999 in Elazig, Turkey. Here twenty fiber optic tips were positioned in the focal plane of the telescope to observe simultaneously at many different latitudes and two different radial distances in the solar corona. The other ends were vertically stacked and placed at the primary focus of the spectrograph. By isolating the K-coronal spectrum from each fiber the temperature and the wind sensitive intensity ratios were calculated.

  4. The Advanced Compton Telescope

    NASA Astrophysics Data System (ADS)

    Boggs, Steven E.; Kurfess, J.; Ryan, J.; Aprile, E.; Gehrels, N.; Hunter, S.; Kippen, M.; Leising, M.; Oberlack, U.; Wunderer, C.; Zoglauer, A. C.; Zych, A.; ACT Collaboration

    2008-03-01

    The Advanced Compton Telescope (ACT) is a NASA Vision Mission designed to survey the gamma-ray sky with unprecedented sensitivity (about 50 times better than the Compton Observatory or INTEGRAL), probing the fires where chemical elements are formed by performing high-resolution spectroscopy of nuclear gamma rays from extragalactic Type Ia supernovae. Dozens of Type 1A SN per year will be detected in nuclear lines gamma rays from 56-Co and 56-Ni, where no definitive gamma ray observations of these have been achieved at this time. The more intense Type 1A events should enable an understanding of the mechanisms in the white dwarf stars responsible for the explosions. ACT also enables a wealth of other science objectives. It will also study the physics of accretion disks in AGN and Galactic compact objects, particle outflows from black holes, nuclear burning in novae, particle acceleration in solar flares, and global nucleosynthesis revealed in the radioactive Milky Way. It will also achieve very sensitive observations of gamma ray bursts with a broad field-of-view instrument. We will review the ACT science goals and results of the previous concept study, and present the goals of our Astrophysics Strategic Mission Concept Study in preparation for the upcoming Decadal Survey.

  5. Multifocal interferometric synthetic aperture microscopy.

    PubMed

    Xu, Yang; Chng, Xiong Kai Benjamin; Adie, Steven G; Boppart, Stephen A; Carney, P Scott

    2014-06-30

    There is an inherent trade-off between transverse resolution and depth of field (DOF) in optical coherence tomography (OCT) which becomes a limiting factor for certain applications. Multifocal OCT and interferometric synthetic aperture microscopy (ISAM) each provide a distinct solution to the trade-off through modification to the experiment or via post-processing, respectively. In this paper, we have solved the inverse problem of multifocal OCT and present a general algorithm for combining multiple ISAM datasets. Multifocal ISAM (MISAM) uses a regularized combination of the resampled datasets to bring advantages of both multifocal OCT and ISAM to achieve optimal transverse resolution, extended effective DOF and improved signal-to-noise ratio. We present theory, simulation and experimental results. PMID:24977909

  6. Multifocal interferometric synthetic aperture microscopy

    PubMed Central

    Xu, Yang; Chng, Xiong Kai Benjamin; Adie, Steven G.; Boppart, Stephen A.; Scott Carney, P.

    2014-01-01

    There is an inherent trade-off between transverse resolution and depth of field (DOF) in optical coherence tomography (OCT) which becomes a limiting factor for certain applications. Multifocal OCT and interferometric synthetic aperture microscopy (ISAM) each provide a distinct solution to the trade-off through modification to the experiment or via post-processing, respectively. In this paper, we have solved the inverse problem of multifocal OCT and present a general algorithm for combining multiple ISAM datasets. Multifocal ISAM (MISAM) uses a regularized combination of the resampled datasets to bring advantages of both multifocal OCT and ISAM to achieve optimal transverse resolution, extended effective DOF and improved signal-to-noise ratio. We present theory, simulation and experimental results. PMID:24977909

  7. The James Webb Space Telescope (JWST), The First Light Machine

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2013-01-01

    Scheduled to begin its 10 year mission after 2018, the James Webb Space Telescope (JWST) will search for the first luminous objects of the Universe to help answer fundamental questions about how the Universe came to look like it does today. At 6.5 meters in diameter, JWST will be the world s largest space telescope. This talk reviews science objectives for JWST and how they drive the JWST architecture, e.g. aperture, wavelength range and operating temperature. Additionally, the talk provides an overview of the JWST primary mirror technology development and fabrication status.

  8. Acoustic phenomena of open cavity airborne Cassegrainian telescopes

    NASA Technical Reports Server (NTRS)

    Van Kuren, J. T.; Otten, L. J., III; Davis, J. A.; Kyrazis, D.

    1974-01-01

    A series of large scale wind tunnel experiments were conducted on a gimbal mounted Cassegrainian telescope enclosed in a shroud with various aerodynamic fairings. The optical aperture was open to the airstream, resulting in acoustic inputs to the telescope. Resonance was shown to be dependent on free stream Mach number, internal cavity and external fairing geometry, and the angle of the plane of the opening relative to the free stream direction. Configurations were found which caused low noise and low unsteady internal loads at the expense of decreased view angle. Air injection over the cavity aided in reducing acoustic resonance.

  9. Status of the James Webb Space Telescope Observatory

    NASA Astrophysics Data System (ADS)

    Bowers, Charles W.; Clampin, M.

    2013-01-01

    The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 ?m to 28 ?m. JWST’s primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, and the formation of evolution of planetary systems. Significant progress has been made in the development of the observatory during the past year and will be reviewed in the context of initial performance measurements of flight hardware, and performance projections from integrated system models of the observatory.

  10. James Webb Space Telescope: The First Light Machine

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2007-01-01

    Scheduled to begin its 10 year mission no sooner than 2013, the James Webb Space Telescope (JWST) will search for the first luminous objects of the Universe to help answer fundamental questions about how the Universe came to look like it does today. At 6.5 meters in diameter, JWST will be the world's largest space telescope. This talk reviews science objectives for JWST and how they drive the JWST architecture, e.g. aperture, wavelength range and operating temperature. Additionally, the talk provides an overview of the JWST primary mirror technology development and fabrication status.

  11. Conically scanned lidar telescope using holographic optical elements

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.; Wilkerson, Thomas D.

    1992-01-01

    Holographic optical elements (HOE) using volume phase holograms make possible a new class of lightweight scanning telescopes having advantages for lidar remote sensing instruments. So far, the only application of HOE's to lidar has been a non-scanning receiver for a laser range finder. We introduce a large aperture, narrow field of view (FOV) telescope used in a conical scanning configuration, having a much smaller rotating mass than in conventional designs. Typically, lidars employ a large aperture collector and require a narrow FOV to limit the amount of skylight background. Focal plane techniques are not good approaches to scanning because they require a large FOV within which to scan a smaller FOV mirror or detector array. Thus, scanning lidar systems have either used a large flat scanning mirror at which the receiver telescope is pointed, or the entire telescope is steered. We present a concept for a conically scanned lidar telescope in which the only moving part is the HOE which serves as the primary collecting optic. We also describe methods by which a multiplexed HOE can be used simultaneously as a dichroic beamsplitter.

  12. Space Telescope Sensitivity and Controls for Exoplanet Imaging

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark

    2012-01-01

    Herein we address design considerations and outline requirements for space telescopes with capabilities for high contrast imaging of exoplanets. The approach taken is to identify the span of potentially detectable Earth-sized terrestrial planets in the habitable zone of the nearest stars within 30 parsecs and estimate their inner working angles, flux ratios, SNR, sensitivities, wavefront error requirements and sensing and control times parametrically versus aperture size. We consider 1, 2, 4, 8 and 16-meter diameter telescope apertures. The achievable science, range of telescope architectures, and the coronagraphic approach are all active areas of research and are all subject to change in a rapidly evolving field. Thus, presented is a snapshot of our current understanding with the goal of limiting the choices to those that appear currently technically feasible. We describe the top-level metrics of inner working angle, contrast and photometric throughput and explore how they are related to the range of target stars. A critical point is that for each telescope architecture and coronagraphic choice the telescope stability requirements have differing impacts on the design for open versus closed-loop sensing and control.

  13. Mirror Illumination and Spillover Measurements of the Atacama Cosmology Telescope

    NASA Technical Reports Server (NTRS)

    Gallardo, Patricio; Dunner, Rolando; Wollack, Ed; Jerez-Hanckes, Carlos

    2012-01-01

    The Atacama Cosmology Telescope (ACT) is a 6 m telescope designed to map the Cosmic Microwave Background (CMB) simultaneously at 145 GHz, 220GHz and 280GHz, The receiver in ACT, the Millimeter Bolometer Array Camera, features 1000 TES bolometers in each band, The detector performance depends critically on the total optical loading, requiring the spmover contributions from the optics to be minimal. This inspired the use of a cold Lyot stop to limit the illumination of the primary and the use of guard rings surrounding the primary and secondary reflectors. Here, we present a direct measurement of the illumination aperture for both reflectors and of the attenuation level outside the main optical path. We used a 145 GHz, 1 m W source and a chopper wheel to produce a time-varying signal with a broad heam proflle, We sampled the response of the camera for different locations of the source, placed in front and beside the primary and secondary mirrors. The aperture of the primary was measured to be 5,72 plus or minus 0,17m in diameter (95 plus or minus 3% of its geometrical size), while the aperture of the secondary yielded 2 plus or minus 0.12m in diameter. Both apertures are consistent with the optical design. Comparing to previous measurements of the beam solid angle from planet observations, we estimate an optical efficiency of 72.3 plus or minus 4,8%. We found that the attenuation outside the primary aperture was -16 plus or minus 2dB, which is below the theoretical expectations, and -22 plus or minus 1 dB outside the secondary aperture, which is consistent with simulations. These results motivated the extension of the baffles surrounding the secondary mirror, with the following reduction in detector optical loading from 2,24 pW to 188pW.

  14. ISS-based Development of Elements and Operations for Robotic Assembly of A Space Solar Power Collector

    NASA Technical Reports Server (NTRS)

    Valinia, Azita; Moe, Rud; Seery, Bernard D.; Mankins, John C.

    2013-01-01

    We present a concept for an ISS-based optical system assembly demonstration designed to advance technologies related to future large in-space optical facilities deployment, including space solar power collectors and large-aperture astronomy telescopes. The large solar power collector problem is not unlike the large astronomical telescope problem, but at least conceptually it should be easier in principle, given the tolerances involved. We strive in this application to leverage heavily the work done on the NASA Optical Testbed Integration on ISS Experiment (OpTIIX) effort to erect a 1.5 m imaging telescope on the International Space Station (ISS). Specifically, we examine a robotic assembly sequence for constructing a large (meter diameter) slightly aspheric or spherical primary reflector, comprised of hexagonal mirror segments affixed to a lightweight rigidizing backplane structure. This approach, together with a structured robot assembler, will be shown to be scalable to the area and areal densities required for large-scale solar concentrator arrays.

  15. Sensitivity of nulling interferometers to extra-solar zodiacal emission (EZE)

    NASA Technical Reports Server (NTRS)

    Angel, Roger

    1998-01-01

    It should be possible to discover and to analyze the atmospheres of Earth-like planets of nearby stars, provided their thermal emission is not overwhelmed by a bright zodiacal cloud in the same system. Nulling interferometers in space, such as the Terrestrial Planet Finder, can efficiently suppress a stellar point source, but there is no way to suppress diffuse emission underlying the planet under study. A cloud much brighter than solar level would cause serious reduction in sensitivity, by its photon shot noise. Since some clouds have been detected that are orders of magnitude brighter, zodiacal measurements of TPF candidates to solar level are critically needed. These could be obtained relatively soon with the largest aperture ground-based interferometers observing in the 10 micron atmospheric window. A cloud would be detectable as an infrared excess, provided the stellar emission (some 10(exp 4) times brighter) is adequately suppressed by destructive interference. Ideally, the ground interferometer should have angular response similar to that of TPF, so as to measure directly the troublesome zodiacal component. The individual elements must be large, for even with approx. 8 m apertures, star cancellation and low thermal background, integration times of at least several hours will be needed to sense the clouds against shot noise from telescope thermal emission. In this paper we compare the sensitivity of TPF and ground based interferometers to a twin of the solar system at 10 pc, using Good's (1994) model of the zodiacal cloud.

  16. GRATIS: a hard x-ray telescope with arcminute resolution

    Microsoft Academic Search

    F. Harrison; S. Kahn; C. J. Hailey; K. Ziock; M. Seiffert

    1992-01-01

    The Gamma-Ray Arcminute Telescope Imaging System (GRATIS) is a balloon-borne coded aperture experiment sensitive in the energy range 20 - 200 keV. This is the first experiment in this energy band capable of resolving sources on arcminute scales. The design incorporates an array of thirty-six imaging scintillation detectors coupled to one-dimensional coded masks which collectively yield a two-dimensional map over

  17. A decametric wavelength radio telescope for interplanetary scintillation observations

    NASA Technical Reports Server (NTRS)

    Cronyn, W. M.; Shawhan, S. D.

    1975-01-01

    A phased array, electrically steerable radio telescope (with a total collecting area of 18 acres), constructed for the purpose of remotely sensing electron density irregularity structure in the solar wind, is presented. The radio telescope is able to locate, map, and track large scale features of the solar wind, such as streams and blast waves, by monitoring a large grid of natural radio sources subject to rapid intensity fluctuation (interplanetary scintillation) caused by the irregularity structure. Observations verify the performance of the array, the receiver, and the scintillation signal processing circuitry of the telescope.

  18. Tethered Formation Configurations: Meeting the Scientific Objectives of Large Aperture and Interferometric Science

    NASA Technical Reports Server (NTRS)

    Farley, Rodger E.; Quinn, David A.

    2004-01-01

    With the success of the Hubble Space Telescope, it has become apparent that new frontiers of science and discovery are made every time an improvement in imaging resolution is made. For the HST working primarily in the visible and near-visible spectrum, this meant designing, building and launching a primary mirror approximately three meters in diameter. Conventional thinking tells us that accomplishing a comparable improvement in resolution at longer wavelengths for Earth and Space Science applications requires a corresponding increase in the size of the primary mirror. For wavelengths in the sub-millimeter range, a very large telescope with an effective aperture in excess of one kilometer in diameter would be needed to obtain high quality angular resolution. Realistically a single aperture this large is practically impossible. Fortunately such large apertures can be constructed synthetically. Possibly as few as three 3 - 4 meter diameter mirrors flying in precision formation could be used to collect light at these longer wavelengths permitting not only very large virtual aperture science to be carried out, but high-resolution interferometry as well. To ensure the longest possible mission duration, a system of tethered spacecraft will be needed to mitigate the need for a great deal of propellant. A spin-stabilized, tethered formation will likely meet these requirements. Several configurations have been proposed which possibly meet the needs of the Space Science community. This paper discusses two of them, weighing the relative pros and cons of each concept. The ultimate goal being to settle on a configuration which combines the best features of structure, tethers and formation flying to meet the ambitious requirements necessary to make future large synthetic aperture and interferometric science missions successful.

  19. Tethered Formation Configurations: Meeting the Scientific Objectives of Large Aperture and Interferometric Science

    NASA Technical Reports Server (NTRS)

    Farley, Rodger E.; Quinn, David A.; Brodeur, Stephen J. (Technical Monitor)

    2001-01-01

    With the success of the Hubble Space Telescope, it has become apparent that new frontiers of science and discovery are made every time an improvement in imaging resolution is made. For the HST working primarily in the visible and near-visible spectrum, this meant designing, building, and launching a primary mirror approximately three meters in diameter. Conventional thinking tells us that accomplishing a comparable improvement in resolution at longer wavelengths for Earth and Space Science applications requires a corresponding increase in the size of the primary mirror. For wavelengths in the sub-millimeter range, a very large telescope with an effective aperture in excess of one kilometer in diameter would be needed to obtain high quality angular resolution. Realistically a single aperture this large is practically impossible. Fortunately such large apertures can be constructed synthetically. Possibly as few as three 34 meter diameter mirrors flying in precision formation could be used to collect light at these longer wavelengths permitting not only very large virtual aperture science to be carried out, but high-resolution interferometry as well. To ensure the longest possible mission duration, a system of tethered spacecraft will be needed to mitigate the need for a great deal of propellant. A spin-stabilized, tethered formation will likely meet these requirements. Several configurations have been proposed which possibly meet the needs of the Space Science community. This paper discusses two of them, weighing the relative pros and cons of each concept. The ultimate goal being to settle on a configuration which combines the best features of structure, tethers, and formation flying to meet the ambitious requirements necessary to make future large synthetic aperture and interferometric science missions successful.

  20. Structural innovations in the Columbus Project - an 11.3 meter optical telescope

    NASA Astrophysics Data System (ADS)

    Davison, Warren B.

    1987-01-01

    The goal of the Steward Observatory's Columbus Project is the construction of an 11.3-m effective aperture telescope by the 500th aniversary of the discovery of America in 1992. The configuration of the telescope is projected to consist of two 8-m diameter F:1 primary mirrors with 14-m center separation; these two mirrors can be supported with a relatively lightweight and simple structure that will facilitate the achievement of high servo performance with modest technology and costs.