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Sample records for compact ariborne spectrographic

  1. Estuarine Landcover Along the Lower Columbia River Estuary Determined from Compact Ariborne Spectrographic Imager (CASI) Imagery, Technical Report 2003.

    SciTech Connect

    Garono, Ralph; Robinson, Rob

    2003-10-01

    Developing an understanding of the distribution and changes in estuarine and riparian habitats is critical to the management of biological resources in the lower Columbia River. In a recently completed comprehensive ecosystem protection and enhancement plan for the lower Columbia River Estuary (CRE), Jerrick (1999) identified habitat loss and modification as one of the key threats to the integrity of the CRE ecosystem. This management plan called for an inventory of habitats as key first step in the CRE long-term restoration effort. While previous studies have produced useful data sets depicting habitat cover types along portions of the lower CRE (Thomas, 1980; Thomas, 1983; Graves et al., 1995; NOAA, 1997; Allen, 1999), no single study has produced a description of the habitats for the entire CRE. Moreover, the previous studies differed in data sources and methodologies making it difficult to merge data or to make temporal comparisons. Therefore, the Lower Columbia River Estuary Partnership (Estuary Partnership) initiated a habitat cover mapping project in 2000. The goal of this project was to produce a data set depicting the current habitat cover types along the lower Columbia River, from its mouth to the Bonneville Dam, a distance of {approx}230-km (Fig. 1) using both established and emerging remote sensing techniques. For this project, we acquired two types of imagery, Landsat 7 ETM+ and Compact Airborne Spectrographic Imager (CASI). Landsat and CASI imagery differ in spatial and spectral resolution: the Landsat 7 ETM+ sensor collects reflectance data in seven spectral bands with a spatial resolution of 30-m and the CASI sensor collects reflectance data in 19 bands (in our study) with a spatial resolution of 1.5-m. We classified both sets of imagery and produced a spatially linked, hierarchical habitat data set for the entire CRE and its floodplain. Landsat 7 ETM+ classification results are presented in a separate report (Garono et al., 2003). This report

  2. Demonstration and design of a compact diffraction limited spectrograph

    NASA Astrophysics Data System (ADS)

    Betters, Christopher H.; Leon-Saval, Sergio G.; Bland-Hawthorn, Joss; Robertson, Gordon

    2012-09-01

    PIMMS IR is a prototype high resolution diraction limited spectrograph operating in the near infrared. Its current conguration has a bandwidth of 8nm centred on 1550nm with a resolving power, λ/Δλ, of 31000 with the option to increase this to ~60000 using a dual grating system. Remarkably, this is 85% of the theoretical limit for Gaussian illumination of a diraction grating. It is based upon the PIMMS#0 (photonic integrated multi-mode micro-spectrograph), a design that utilises the multi-mode to single-mode conversion of the photonic lantern. By feeding the spectrograph with the single-mode bres we are able to design and build a spectrograph whose performance is diraction limited and independent of the input source (i.e. a telescope) it is attached to. The spectrograph has with a throughput of ~70% (that is the light from the single-mode entrance slit that lands on the detector). The spectrograph is also extremely compact with a footprint of just 450mm x 190mm. Here we present the design of PIMMS IR and its performance characteristics determined from ray tracing, physical optics simulations and experimental measurements.Δ

  3. Compact low resolution spectrograph, an imaging and long slit spectrograph for robotic telescopes

    SciTech Connect

    Rabaza, O.; Zeman, J.; Hudec, R.; Sabau-Graziati, L.

    2013-11-15

    The COmpact LOw REsolution Spectrograph (COLORES) is a compact and lightweight (13 kg) f/8 imaging spectrograph designed for robotic telescopes, now installed and operating on the TELMA, a rapid-slewing 60 cm telescope of the BOOTES-2 observatory in Málaga (Spain). COLORES is a multi-mode instrument that enables the observer to seamlessly switch between low-dispersion spectroscopy and direct imaging modes during an observation. In this paper, we describe the instrument and its development, from the initial scientific requirements through the optical design process to final configuration with theoretical performance calculations. The mechanical and electronic design is described, methods of calibration are discussed and early laboratory and scientific results are shown.

  4. Compact low resolution spectrograph, an imaging and long slit spectrograph for robotic telescopes.

    PubMed

    Rabaza, O; Jelinek, M; Castro-Tirado, A J; Cunniffe, R; Zeman, J; Hudec, R; Sabau-Graziati, L; Ruedas-Sánchez, J

    2013-11-01

    The COmpact LOw REsolution Spectrograph (COLORES) is a compact and lightweight (13 kg) f/8 imaging spectrograph designed for robotic telescopes, now installed and operating on the TELMA, a rapid-slewing 60 cm telescope of the BOOTES-2 observatory in Málaga (Spain). COLORES is a multi-mode instrument that enables the observer to seamlessly switch between low-dispersion spectroscopy and direct imaging modes during an observation. In this paper, we describe the instrument and its development, from the initial scientific requirements through the optical design process to final configuration with theoretical performance calculations. The mechanical and electronic design is described, methods of calibration are discussed and early laboratory and scientific results are shown.

  5. Compact low resolution spectrograph, an imaging and long slit spectrograph for robotic telescopes

    NASA Astrophysics Data System (ADS)

    Rabaza, O.; Jelinek, M.; Castro-Tirado, A. J.; Cunniffe, R.; Zeman, J.; Hudec, R.; Sabau-Graziati, L.; Ruedas-Sánchez, J.

    2013-11-01

    The COmpact LOw REsolution Spectrograph (COLORES) is a compact and lightweight (13 kg) f/8 imaging spectrograph designed for robotic telescopes, now installed and operating on the TELMA, a rapid-slewing 60 cm telescope of the BOOTES-2 observatory in Málaga (Spain). COLORES is a multi-mode instrument that enables the observer to seamlessly switch between low-dispersion spectroscopy and direct imaging modes during an observation. In this paper, we describe the instrument and its development, from the initial scientific requirements through the optical design process to final configuration with theoretical performance calculations. The mechanical and electronic design is described, methods of calibration are discussed and early laboratory and scientific results are shown.

  6. Solar glint suppression in compact planetary ultraviolet spectrographs

    NASA Astrophysics Data System (ADS)

    Davis, Michael W.; Cook, Jason C.; Grava, Cesare; Greathouse, Thomas K.; Gladstone, G. Randall; Retherford, Kurt D.

    2015-08-01

    Solar glint suppression is an important consideration in the design of compact photon-counting ultraviolet spectrographs. Southwest Research Institute developed the Lyman Alpha Mapping Project for the Lunar Reconnaissance Orbiter (launch in 2009), and the Ultraviolet Spectrograph on Juno (Juno-UVS, launch in 2011). Both of these compact spectrographs revealed minor solar glints in flight that did not appear in pre-launch analyses. These glints only appeared when their respective spacecraft were operating outside primary science mission parameters. Post-facto scattered light analysis verifies the geometries at which these glints occurred and why they were not caught during ground testing or nominal mission operations. The limitations of standard baffle design at near-grazing angles are discussed, as well as the importance of including surface scatter properties in standard stray light analyses when determining solar keep-out efficiency. In particular, the scattered light analysis of these two instruments shows that standard "one bounce" assumptions in baffle design are not always enough to prevent scattered sunlight from reaching the instrument focal plane. Future builds, such as JUICE-UVS, will implement improved scattered and stray light modeling early in the design phase to enhance capabilities in extended mission science phases, as well as optimize solar keep out volume.

  7. Stratospheric NO2 Concentration Determined by DOAS Using Compact Spectrographs

    NASA Astrophysics Data System (ADS)

    Raponi, Marcelo M.; Wolfram, Elian; Rinaldi, Horacio; Rosales, Alejandro; Quel, Eduardo J.; Tocho, Jorge O.

    2008-04-01

    In this work we present the results for stratospheric NO2-total column concentration retrieved by DOAS (Differential Optical Absorption Spectroscopy) performed with compact spectrographs. The behavior for three different spectrographs (MonoSpec 27, Jarrell-Ash; HR4000, Ocean Optics and Mechelle 900, Multichannel Instruments) are analyzed making one intercomparison in the facilities of the LIDAR Division of CEILAP (CITEFA—CONICET), in Villa Martelli, Argentina (34.5° S, 58.5° W, 20 m amsl). The three instruments have a similar resolution (approximately 0.1 nm) but operate with different optical configurations and have optical sensors of different characteristics; two of them have cooling capability and the other one (HR4000) operates at room temperature. The NO2 concentration was obtained from spectral results at twilight using solar noon spectra as reference. In all cases zenithal diffuse irradiance was used. The NO2 absorption cross section given by S. Voigt and J. P. Burrows (University of Bremen—Institute of Environmental Physics) corresponding to 223 °K and 100 mbar is used. Results are compared with public data corresponding to ground-based device or to instruments mounted in satellites. These atmospheric soundings are of extreme importance to understand the roll that plays the stratospheric NO2 in the associated phenomena of destruction and formation of ozone in the low stratosphere at middle latitudes.

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

    NASA Astrophysics Data System (ADS)

    Robertson, J. Gordon; Bland-Hawthorn, Joss

    2012-09-01

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

  9. PIMMS échelle: the next generation of compact diffraction limited spectrographs for arbitrary input beams

    NASA Astrophysics Data System (ADS)

    Betters, Christopher H.; Leon-Saval, Sergio G.; Bland-Hawthorn, Joss; Richards, Samuel N.; Birks, Tim A.; Gris-Sánchez, Itandehui

    2014-07-01

    PIMMS échelle is an extension of previous PIMMS (photonic integrated multimode spectrograph) designs, enhanced by using an échelle diffraction grating as the primary dispersing element for increased spectral band- width. The spectrograph operates at visible wavelengths (550 to 780nm), and is capable of capturing ~100 nm of R > 60, 000 (λ/(triangle)λ) spectra in a single exposure. PIMMS échelle uses a photonic lantern to convert an arbitrary (e.g. incoherent) input beam into N diffraction-limited outputs (i.e. N single-mode fibres). This allows a truly diffraction limited spectral resolution, while also decoupling the spectrograph design from the input source. Here both the photonic lantern and the spectrograph slit are formed using a single length of multi-core fibre. A 1x19 (1 multi-mode fiber to 19 single-mode fibres) photonic lantern is formed by tapering one end of the multi-core fibre, while the other end is used to form a TIGER mode slit (i.e. for a hexagonal grid with sufficient spacing and the correct orientations, the cores of the multi-core fibre can be dispersed such that they do not overlap without additional reformatting). The result is an exceptionally compact, shoebox sized, spectrograph that is constructed primarily from commercial off the shelf components. Here we present a brief overview of the échelle spectrograph design, followed by results from on-sky testing of the breadboard mounted version of the spectrograph at the `UK Schmidt Telescope'.

  10. RHEA: the ultra-compact replicable high-resolution exoplanet and Asteroseismology spectrograph

    NASA Astrophysics Data System (ADS)

    Feger, Tobias; Bacigalupo, Carlos; Bedding, Timothy R.; Bento, Joao; Coutts, David W.; Ireland, Michael J.; Parker, Quentin A.; Rizzuto, Aaron; Spaleniak, Izabela

    2014-08-01

    We present the opto-mechanical design and the characterization of the Replicable High-resolution Exoplanet and Asteroseismology (RHEA) spectrograph. RHEA is an ultra-compact fiber-fed echelle spectrograph designed to be used at 0.2-0.4 m class robotic telescopes where long term dedicated projects are possible. The instrument will be primarily used for radial velocity (RV) studies of low to intermediate-mass giant stars for the purpose of searching for hot Jupiters and using asteroseismology to simultaneously measure the host star parameters and de-correlate stellar pulsations. The optical design comprises a double-pass (i.e. near Littrow) configuration with prism cross-disperser and single-mode fiber (SMF) input. The spectrograph has a resolving power of R>70,000 and operates at 430-670 nm with minimum order separation of ~180 μm. This separation allows a 1x6 photonic lantern integration at a later stage which is currently under development. The current design is built with the aim of creating an inexpensive and replicable unit. The spectrograph is optimised for long-baseline RV observations through careful temperature stabilisation and simultaneous wavelength calibration. As a further improvement the echelle grating is housed in a vacuum chamber to maintain pressure stability. The performance of the current prototype is currently being tested on a 0.4 m telescope at the Macquarie University Observatory.

  11. Implementation of a high throughput spectrograph for Thomson scattering measurements on the Compact Toriodal Hybrid

    NASA Astrophysics Data System (ADS)

    Goforth, Matthew; Traverso, Peter; Maurer, David

    2013-10-01

    To better understand the equilibrium and stability of Compact Toroidal Hybrid (CTH) plasmas, a multipoint Thomson scattering system is under development at Auburn University. Thomson scattering will be performed at 532 nm using a frequency doubled Continuum PL DLS Nd:YAG laser. The Thomson scattered light will be measured using a high throughput HoloSpec f/1.8i imaging spectrograph with in-line interference filter for spectral discrimination of stray laser light. An image intensified charge coupled device (ICCD) camera employing a Gen III photocathode with quantum efficiency of approximately 50% near the frequency doubled laser line is planned as the detection element for the scattered light. Bench and CTH impurity line emission measurements will be presented quantifying spectrometer and ICCD performance and suitability for scattering measurements over the visible spectral region near 532 nm. This work has been supported by US Department of Energy Grant No. DE-FG02-00ER54610 and the Auburn University Undergraduate Research Fellowship Program.

  12. [Estimating Leaf Area Index of Crops Based on Hyperspectral Compact Airborne Spectrographic Imager (CASI) Data].

    PubMed

    Tang, Jian-min; Liao, Qin-hong; Liu, Yi-qing; Yang, Gui-jun; Feng, Hai-kuanr; Wang, Ji-hua

    2015-05-01

    The fast estimation of leaf area index (LAI) is significant for learning the crops growth, monitoring the disease and insect, and assessing the yield of crops. This study used the hyperspectral compact airborne spectrographic imager (CASI) data of Zhangye city, in Heihe River basin, on July 7, 2012, and extracted the spectral reflectance accurately. The potential of broadband and red-edge vegetation index for estimating the LAI of crops was comparatively investigated by combined with the field measured data. On this basis, the sensitive wavebands for estimating the LAI of crops were selected and two new spectral indexes (NDSI and RSI) were constructed, subsequently, the spatial distribution of LAI in study area was analyzed. The result showed that broadband vegetation index NDVI had good effect for estimating the LAI when the vegetation coverage is relatively lower, the R2 and RMSE of estimation model were 0. 52, 0. 45 (p<0. 01) , respectively. For red-edge vegetation index, CIred edge took the different crop types into account fully, thus it gained the same estimation accuracy with NDVI. NDSI(569.00, 654.80) and RSI(597.60, 654.80) were constructed by using waveband combination algorithm, which has superior estimation results than NDVI and CIred edge. The R2 of estimation model used NDSI(569.00, 654.80) was 0. 77(p<0. 000 1), it mainly used the wavebands near the green peak and red valley of vegetation spectrum. The spatial distribution map of LAI was made according to the functional relationship between the NDSI(569.00, 654.80) and LAI. After analyzing this map, the LAI values were lower in the northwest of study area, this indicated that more fertilizer should be increased in this area. This study can provide technical support for the agricultural administrative department to learn the growth of crops quickly and make a suitable fertilization strategy. PMID:26415459

  13. Mini-Spec: A Compact, Fiber-Coupled, VPH Grating Spectrograph for Small Observatories

    NASA Astrophysics Data System (ADS)

    Nations, H. L.; Haynes, P.; Brewer, P.

    2003-05-01

    We report on the development and testing of what we believe to be the first VPH grating based spectrograph developed primarily for use at telescopes of modest aperture. To date, the most common instrument suite for such observatories is typically that of a CCD camera with attached filter wheel. While there is no doubt that a wide range of interesting and good science has been done with such instrumentation, the addition of a robust and easy to operate spectrograph would greatly increase the utility of such installations. While some commercial spectrographs exist for use on small telescopes, the authors have found them to be, with few exceptions, either inefficient, difficult for inexperienced students or amateurs to use, or not remotely operable. Correcting these deficiencies is thus the primary motivation for Mini-Spec. The design of Mini-Spec has been influenced by previous work the authors have done on a full-sized fiber-coupled spectrograph (Nations and Pierce, 2002). Mini-Spec uses some of those original design features, only reduced drastically in size. This size reduction (the spectrograph fits within a 7 inch cube), along with a much more careful choice of some critical components, has resulted in a dramatic reduction in cost. The spectrograph uses a highly efficient 1200 l/mm, 40 mm diameter vph grating on loan from Richard Rallison. Focus, central wavelength selection, and comparison lamps are all controlled via an RS-232 link and a custom Visual Basic GUI. Sample spectra of stellar and non-stellar targets will be presented along with a discussion of research projects admirably suited for this instrument. Funding for equipment has been provided by a NASA EPSCoR grant to PI Ron Canterna. HLN has been partially funded by a Wyoming Space Grant Faculty Fellowship.

  14. Design and performance of a new generation, compact, low cost, very high Doppler precision and resolution optical spectrograph

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Zhao, Bo; Powell, Scott; Wang, Ji; Fletcher, Adam; Chang, Liang; Groot, John; Wan, Xiaoke; Jakeman, Hali; Myers, Derek; Grafer, Elliot; Liu, Jian; Varosi, Frank; Schofield, Sidney; Moore, Alexandria; van Olphen, Maria-Ines; Katz, Jordan; Barnes, Rory

    2012-09-01

    This paper is to report the design and performance of a very high Doppler precision cross-dispersed echelle spectrograph, EXtremely high Precision ExtrasolaR planet Tracker III (EXPERT-III), as part of a global Exoplanet Tracker (ET) network. The ET network is designed to hunt low mass planets, especially habitable rocky planets, around GKM dwarfs. It has an extremely high spectral resolution (EHR) mode of R=110,000 and a high resolution (HR) mode of R=56,000 and can simultaneously cover 0.38-0.9 μm with a 4kx4k back-illuminated Fairchild CCD detector with a single exposure. EXPERT-III is optimized for high throughput by using two-prisms cross-disperser and a large core diameter fiber (2 arcsec on sky, or 80 μm at f/4) to collect photons from the Kitt Peak National Observatory (KPNO) 2.1m telescope. The average overall detection efficiency is ~6% from above the atmosphere to the detector for the EHR Mode and about 11% for the HR mode. The extremely high spectral resolution in a compact design (the spectrograph dimension, 1.34x0.8x0.48 m) is realized by coupling the single input 80 μm telescope fiber into four 40 μm fibers and re-arranging the four small core diameter fibers into a linear fiber slit array (a one-to-four fiber image slicer). EXPERT-III is operated in a vacuum chamber with temperature controlled to ~2 milli-Kelvin rms for an extended period of time. The radial velocity (RV) drift is controlled to within 10 meters/second (m/s) over a month. EXPERT-III can reach a photon noise limited RV measurement precision of ~0.3 m/s for a V=8 mag GKM type dwarf with small rotation (vsini =2 km/s) in a 15 min exposure. EXPERT-III's RV measurement uncertainties for bright stars are primarily limited by the Thorium-Argon (ThAr) calibration source (~0.5 m/s). EXPERT-III will serve as an excellent public accessible high resolution optical spectroscope facility at the KPNO 2.1m telescope.

  15. A robotic, compact, and extremely high resolution optical spectrograph for a close-in super-Earth survey

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Powell, Scott; Zhao, Bo; Varosi, Frank; Ma, Bo; Sithajan, Sirinrat; Liu, Jian; Li, Rui; Grieves, Nolan; Schofield, Sidney; Avner, Louis; Jakeman, Hali; Yoder, William A.; Gittelmacher, Jakob A.; Singer, Michael A.; Muterspaugh, Matthew; Williamson, Michael; Maxwell, J. E.

    2014-08-01

    One of the most astonishing results from the HARPS and Kepler planet surveys is the recent discovery of close-in super-Earths orbiting more than half of FGKM dwarfs. This new population of exoplanets represents the most dominant class of planetary systems known to date, is totally unpredicted by the classical core-accretion disk planet formation model. High cadence and high precision Doppler spectroscopy is the key to characterize properties of this new population and constrain planet formation models. A new robotic, compact high resolution optical spectrograph, called TOU (formerly called EXPERT-III), was commissioned at the Automatic Spectroscopic Telescope (AST) at Fairborn Observatory in Arizona in July 2013 and has produced a spectral resolution of about 100,000 and simultaneous wavelength coverage of 0.38-0.9 μm with a 4kx4k back-illuminated Fairchild CCD detector. The instrument holds a very high vacuum of 1 micro torr and about 2 mK temperature stability over a month. The early on-sky RV measurements show that this instrument is approaching a Doppler precision of 1 m/s (rms) for bright reference stars (such as Tau Ceti) with 5 min exposures and better than 3 m/s (P-V, RMS~1 m/s) daily RV stability before calibration exposures are applied. A pilot survey of 20 V<9 FGK dwarfs, including known super-Earth systems and known RV stable stars, is being launched and every star will be observed ~100 times over ~300 days time window between this summer and next spring, following up with a full survey of ~150 V< 10 FGKM dwarfs in 2015-2017.

  16. Spitzer/infrared spectrograph investigation of mipsgal 24 μm compact bubbles: low-resolution observations

    SciTech Connect

    Nowak, M.; Flagey, N.; Noriega-Crespo, A.; Carey, S. J.; Van Dyk, S. D.; Billot, N.; Paladini, R.

    2014-12-01

    We present Spitzer/InfraRed Spectrograph (IRS) low-resolution observations of 11 compact circumstellar bubbles from the MIPSGAL 24 μm Galactic plane survey. We find that this set of MIPSGAL bubbles (MBs) is divided into two categories and that this distinction correlates with the morphologies of the MBs in the mid-infrared (IR). The four MBs with central sources in the mid-IR exhibit dust-rich, low-excitation spectra, and their 24 μm emission is accounted for by the dust continuum. The seven MBs without central sources in the mid-IR have spectra dominated by high-excitation gas lines (e.g., [O IV] 26.0 μm, [Ne V] 14.3 and 24.3 μm, and [Ne III] 15.5 μm), and the [O IV] line accounts for 50% to almost 100% of the 24 μm emission in five of them. In the dust-poor MBs, the [Ne V] and [Ne III] line ratios correspond to high-excitation conditions. Based on comparisons with published IRS spectra, we suggest that the dust-poor MBs are highly excited planetary nebulae (PNs) with peculiar white dwarfs (e.g., Wolf-Rayet [WR] and novae) at their centers. The central stars of the four dust-rich MBs are all massive star candidates. Dust temperatures range from 40 to 100 K in the outer shells. We constrain the extinction along the lines of sight from the IRS spectra. We then derive distance, dust masses, and dust production rate estimates for these objects. These estimates are all consistent with the nature of the central stars. We summarize the identifications of MBs made to date and discuss the correlation between their mid-IR morphologies and natures. Candidate Be/B[e]/luminous blue variable and WR stars are mainly 'rings' with mid-IR central sources, whereas PNs are mostly 'disks' without mid-IR central sources. Therefore we expect that most of the 300 remaining unidentified MBs will be classified as PNs.

  17. MEGARA spectrograph optics

    NASA Astrophysics Data System (ADS)

    Carrasco, E.; Sánchez-Blanco, E.; García-Vargas, M. L.; Gil de Paz, A.; Páez, G.; Gallego, J.; Sánchez, F. M.; Vílchez, J. M.

    2012-09-01

    MEGARA is the next optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for Gran Telescopio Canarias. The instrument offers two IFUs plus a Multi-Object Spectroscopy (MOS) mode: a large compact bundle covering 12.5 arcsec x 11.3 arcsec on sky with 100 μm fiber-core; a small compact bundle, of 8.5 arcsec x 6.7 arcsec with 70 μm fiber-core and a fiber MOS positioner that allows to place up to 100 mini-bundles, 7 fibers each, with 100 μm fiber-core, within a 3.5 arcmin x 3.5 arcmin field of view, around the two IFUs. The fibers, organized in bundles, end in the pseudo-slit plate, which will be placed at the entrance focal plane of the MEGARA spectrograph. The large IFU and MOS modes will provide intermediate to high spectral resolutions, R=6800-17000. The small IFU mode will provide R=8000-20000. All these resolutions are possible thanks to a spectrograph design based in the used of volume phase holographic gratings in combination with prisms to keep fixed the collimator and camera angle. The MEGARA optics is composed by a total of 53 large optical elements per spectrograph: the field lens, the collimator and the camera lenses plus the complete set of pupil elements including holograms, windows and prisms. INAOE, a partner of the GTC and a partner of MEGARA consortium, is responsible of the optics manufacturing and tests. INAOE will carry out this project working in an alliance with CIO. This paper summarizes the status of MEGARA spectrograph optics at the Preliminary Design Review, held on March 2012.

  18. Field Raman spectrograph for environmental analysis

    SciTech Connect

    Haas, J.W. III; Forney, R.W.; Carrabba, M.M.

    1995-10-01

    This project entails the development of a compact raman spectrograph for field screening and monitoring of a wide variety of wastes, pollutants, and corrosion products in tanks, and environmental materials. The design of a fiber optic probe for use with the spectrograph is also discussed.

  19. The BigBOSS spectrograph

    NASA Astrophysics Data System (ADS)

    Jelinsky, Patrick; Bebek, Chris; Besuner, Robert; Carton, Pierre-Henri; Edelstein, Jerry; Lampton, Michael; Levi, Michael E.; Poppett, Claire; Prieto, Eric; Schlegel, David; Sholl, Michael

    2012-09-01

    BigBOSS is a proposed ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with a 14,000 square degree galaxy and quasi-stellar object redshift survey. It consists of a 5,000- fiber-positioner focal plane feeding the spectrographs. The optical fibers are separated into ten 500 fiber slit heads at the entrance of ten identical spectrographs in a thermally insulated room. Each of the ten spectrographs has a spectral resolution (λ/Δλ) between 1500 and 4000 over a wavelength range from 360 - 980 nm. Each spectrograph uses two dichroic beam splitters to separate the spectrograph into three arms. It uses volume phase holographic (VPH) gratings for high efficiency and compactness. Each arm uses a 4096x4096 15 μm pixel charge coupled device (CCD) for the detector. We describe the requirements and current design of the BigBOSS spectrograph. Design trades (e.g. refractive versus reflective) and manufacturability are also discussed.

  20. Designing Echelle Spectrographs

    NASA Technical Reports Server (NTRS)

    Dantzler, A.

    1987-01-01

    Performance numbers and output maps computed from inputs supplied by user. Echelle Spectrograph Design Aid program (EGRAM) aids in design of spectrographic systems that utilize echelle/first-order crossdisperser combinations. Optical combination causes two-dimensional echellogram to fall on detector. Describes echellogram with enough detail to enable user to judge effectively feasibility of spectrograph design. By iteratively altering system parameters, desired echellogram achieved without making physical model. Calculates system parameters accurately to first order and compare favorably to results from raytracing techniques. EGRAM written in two versions. FORTRAN 77, and Microsoft BASIC A.

  1. Immersion echelle spectrograph

    DOEpatents

    Stevens, Charles G.; Thomas, Norman L.

    2000-01-01

    A small spectrograph containing no moving components and capable of providing high resolution spectra of the mid-infrared region from 2 microns to 4 microns in wavelength. The resolving power of the spectrograph exceeds 20,000 throughout this region and at an optical throughput of about 10.sup.-5 cm.sup.2 sr. The spectrograph incorporates a silicon immersion echelle grating operating in high spectral order combined with a first order transmission grating in a cross-dispersing configuration to provide a two-dimensional (2-D) spectral format that is focused onto a two-dimensional infrared detector array. The spectrometer incorporates a common collimating and condensing lens assembly in a near aberration-free axially symmetric design. The spectrometer has wide use potential in addition to general research, such as monitoring atmospheric constituents for air quality, climate change, global warming, as well as monitoring exhaust fumes for smog sources or exhaust plumes for evidence of illicit drug manufacture.

  2. PRISM Spectrograph Optical Design

    NASA Technical Reports Server (NTRS)

    Chipman, Russell A.

    1995-01-01

    The objective of this contract is to explore optical design concepts for the PRISM spectrograph and produce a preliminary optical design. An exciting optical configuration has been developed which will allow both wavelength bands to be imaged onto the same detector array. At present the optical design is only partially complete because PRISM will require a fairly elaborate optical system to meet its specification for throughput (area*solid angle). The most complex part of the design, the spectrograph camera, is complete, providing proof of principle that a feasible design is attainable. This camera requires 3 aspheric mirrors to fit inside the 20x60 cm cross-section package. A complete design with reduced throughput (1/9th) has been prepared. The design documents the optical configuration concept. A suitable dispersing prism material, CdTe, has been identified for the prism spectrograph, after a comparison of many materials.

  3. Single Mode, Extreme Precision Doppler Spectrographs

    NASA Astrophysics Data System (ADS)

    Schwab, Christian; Leon-Saval, Sergio G.; Betters, Christopher H.; Bland-Hawthorn, Joss; Mahadevan, Suvrath

    2014-04-01

    The `holy grail' of exoplanet research today is the detection of an earth-like planet: a rocky planet in the habitable zone around a main-sequence star. Extremely precise Doppler spectroscopy is an indispensable tool to find and characterize earth-like planets; however, to find these planets around solar-type stars, we need nearly one order of magnitude better radial velocity (RV) precision than the best current spectrographs provide. Recent developments in astrophotonics (Bland-Hawthorn & Horton 2006, Bland-Hawthorn et al. 2010) and adaptive optics (AO) enable single mode fiber (SMF) fed, high resolution spectrographs, which can realize the next step in precision. SMF feeds have intrinsic advantages over multimode fiber or slit coupled spectrographs: The intensity distribution at the fiber exit is extremely stable, and as a result the line spread function of a well-designed spectrograph is fully decoupled from input coupling conditions, like guiding or seeing variations (Ihle et al. 2010). Modal noise, a limiting factor in current multimode fiber fed instruments (Baudrand & Walker 2001), can be eliminated by proper design, and the diffraction limited input to the spectrograph allows for very compact instrument designs, which provide excellent optomechanical stability. A SMF is the ideal interface for new, very precise wavelength calibrators, like laser frequency combs (Steinmetz et al. 2008, Osterman et al. 2012), or SMF based Fabry-Perot Etalons (Halverson et al. 2013). At near infrared wavelengths, these technologies are ready to be implemented in on-sky instruments, or already in use. We discuss a novel concept for such a spectrograph.

  4. Replicated spectrographs in astronomy

    NASA Astrophysics Data System (ADS)

    Hill, Gary J.

    2014-06-01

    As telescope apertures increase, the challenge of scaling spectrographic astronomical instruments becomes acute. The next generation of extremely large telescopes (ELTs) strain the availability of glass blanks for optics and engineering to provide sufficient mechanical stability. While breaking the relationship between telescope diameter and instrument pupil size by adaptive optics is a clear path for small fields of view, survey instruments exploiting multiplex advantages will be pressed to find cost-effective solutions. In this review we argue that exploiting the full potential of ELTs will require the barrier of the cost and engineering difficulty of monolithic instruments to be broken by the use of large-scale replication of spectrographs. The first steps in this direction have already been taken with the soon to be commissioned MUSE and VIRUS instruments for the Very Large Telescope and the Hobby-Eberly Telescope, respectively. MUSE employs 24 spectrograph channels, while VIRUS has 150 channels. We compare the information gathering power of these replicated instruments with the present state of the art in more traditional spectrographs, and with instruments under development for ELTs. Design principles for replication are explored along with lessons learned, and we look forward to future technologies that could make massively-replicated instruments even more compelling.

  5. Kyoto Tridimensional Spectrograph II

    NASA Astrophysics Data System (ADS)

    Sugai, Hajime; Ohtani, Hiroshi; Ishigaki, Tsuyoshi; Hayashi, Tadashi; Ozaki, Shinobu; Hattori, Takashi; Ishii, M.; Sasaki, Minoru; Takeyama, Norihide

    1998-07-01

    We are building the second version of the Kyoto Tridimensional Spectrograph (Ohtani et al., this symposium). This will be mounted on the MAGNUM, a 2-m telescope under construction at Haleakala, and also on the SUBARU. The spectrograph has four observational modes: Fabry-Perot imager, integral field spectrograph (IFS) with a microlens array, long-slit spectrograph, and filter-imaging modes. The new spectrograph is significantly better than the first version in several ways. The IFS has as many as 37 X 37 microlenses, each of which subtends 0' .39 at the MAGNUM. The optics is designed to be used in wide wavelength ranges from 360 nm to 900 nm. The transmission at any wavelength between 370 and 900 nm is designed to exceed 50% for the collimator plus camera system, and to reach almost 40% even at 360 nm. In order to achieve high efficiency at short wavelengths, we use an anti- reflection coated backside-illuminated 2K X 2K CCD. We are also planning a further improvement by using multi-layer anti- reflection coatings for lenses, in collaboration with National Astronomical Observatory, Japan. In order to assure good image quality under a severe weight limit of 150 kg for this instrument, we have carried out mechanical design by calculating the flexure of the instrument for all telescope attitudes with finite element analysis, and succeeded in limiting the maximum flexure to 30 micrometer. This does not degrade image quality. The movements on the CCD of the light from the center of the focal plane have also been simulated, depending on the telescope attitudes. This is important to obtain not only a good image, but also a correct flat field and wavelength calibration in the IFS mode. The movements are expected to be confined almost within one pixel for an attitude, which is considered to be small enough.

  6. Immersion echelle spectrograph

    SciTech Connect

    Stevens, C.G.; Thomas, N.L.

    2000-06-20

    A small spectrograph is disclosed containing no moving components and capable of providing high resolution spectra of the mid-infrared region from 2 microns to 4 microns in wavelength. The resolving power of the spectrograph exceeds 20,000 throughout this region and at an optical throughput of about 10{sup {minus}5}cm{sup 2}sr. The spectrograph incorporates a silicon immersion echelle grating operating in high spectral order combined with a first order transmission grating in a cross-dispersing configuration to provide a two-dimensional (2-D) spectral format that is focused onto a two-dimensional infrared detector array. The spectrometer incorporates a common collimating and condensing lens assembly in a near aberration-free axially symmetric design. The spectrometer has wide use potential in addition to general research, such as monitoring atmospheric constituents for air quality, climate change, global warming, as well as monitoring exhaust fumes for smog sources or exhaust plumes for evidence of illicit drug manufacture.

  7. THE COSMIC ORIGINS SPECTROGRAPH

    SciTech Connect

    Green, James C.; Michael Shull, J.; Snow, Theodore P.; Stocke, John; Froning, Cynthia S.; Osterman, Steve; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Sembach, Kenneth; Linsky, Jeffrey L.; Savage, Blair D.; Siegmund, Oswald H. W.; Spencer, John; Alan Stern, S.; Welsh, Barry; and others

    2012-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in 2009 May, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F{sub {lambda}} Almost-Equal-To 1.0 Multiplication-Sign 10{sup -14} erg cm{sup -2} s{sup -1} A{sup -1}, COS can achieve comparable signal to noise (when compared to Space Telescope Imaging Spectrograph echelle modes) in 1%-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (2009 September-2011 June) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is nine times than sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of 2011 June. COS has measured, for the first time with high reliability, broad Ly{alpha} absorbers and Ne VIII in the intergalactic medium, and observed the He II reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  8. Million object spectrograph

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.; Ritter, Joseph M.

    2008-07-01

    A new class of astronomical telescope with a primary objective grating (POG) has been studied as an alternative to mirrors. Nineteenth century POG telescopes suffered from low resolution and ambiguity of overlapping spectra as well as background noise. The present design uses a conventional secondary spectrograph to disambiguate all objects while enjoying a very wide instantaneous field-of-view, up to 40°. The POG competes with mirrors, in part, because diffraction gratings provide the very chromatic dispersion that mirrors defeat. The resulting telescope deals effectively with long-standing restrictions on multiple object spectrographs (MOS). The combination of a POG operating in the first-order, coupled to a spectrographic astronomical telescope, isolates spectra from all objects in the free spectral range of the primary. First disclosed as a concept in year 2002, a physical proof-of-principle is now reported. The miniature laboratory model used a 50 mm plane grating primary and was able to disambiguate between objects appearing at angular resolutions of 55 arcseconds and spectral spacings of 0.15 nm. Astronomical performance is a matter of increasing instrument size. A POG configured according to our specifications has no moving parts during observations and is extensible to any length that can be held flat to tolerances approaching float glass. The resulting telescope could record over one million spectra per night of objects in a line of right ascension. The novel MOS does not require pre-imaging to start acquisition of uncharted star fields. Problems are anticipated in calibration and integration time. We propose means to ameliorate them.

  9. Ultraviolet spectrograph lens

    SciTech Connect

    Brixner, B.; Winkler, M.A.

    1981-01-01

    A 700-mm f/4.7 spectrograph camera lens was designed for imaging spectral lines in the 200 to 400-nm region on a 120-mm flat image field. Lens elements of fused silica and crystalline calcium fluoride have so little secondary spectrum that raytracing calculations predict a monochromatic resolution limit of 30 lines/mm without refocusing in the 238- to 365-nm region. Light scattering at the polished calcium-fluoride surfaces is avoided by sandwiching the fluoride elements between fused silica and cementing with silicone fluid. The constructed lens makes good spectrograms.

  10. Ultraviolet-spectrograph lens

    SciTech Connect

    Brixner, B.; Winkler, M.A.

    1981-01-01

    A 700-mm f/4.7 spectrograph camera lens was designed for imaging spectral lines in the 200- to 400-nm region on a 120-mm flat image field. Lens elements of fused silica and crystal calcium fluoride give such good achromatization that raytracing calculations predict a resolution limit of 30 lines/mm without refocusing in the 238- to 365-nm region. Light scattering at the polished calcium-fluoride surfaces is avoided by sandwiching the fluoride elements between fused silica and cementing with silicone fluid. The constructed lens makes good spectrograms.

  11. A Spectrograph for BigBOSS

    NASA Astrophysics Data System (ADS)

    CARTON, Pierre-Henri; Bebek, C.; Cazaux, S.; Ealet, A.; Eppelle, D.; Kneib, J.; Karst, P.; levi, M.; magneville, C.; Palanque-Delabrouille, N.; Ruhlmann-Kleider, V.; Schlegel, D.; Yeche, C.

    2012-01-01

    The Big-Boss spectrographs assembly will take in charge the light from the fiber output to the detector, including the optics, gratings, mechanics and cryostats. The 5000 fibers are split in 10 bundles of 500 ones. Each of these channel feed one spectrograph. The full bandwidth from 0.36µm to 1.05µm is split in 3 bands. Each channel is composed with one collimator (doublet lenses), a VPH grating, and a 6 lenses camera. The 500 fiber spectrum are imaged onto a 4kx4k detector thanks to the F/2 camera. Each fiber core is imaged onto 4 pixels. Each channel of the BigBOSS spectrograph will be equipped with a single-CCD camera, resulting in 30 cryostats in total for the instrument. Based on its experience of CCD cameras for projects like EROS and MegaCam, CEA/Saclay has designed small and autonomous cryogenic vessels which integrate cryo-cooling, CCD positioning and slow control interfacing capabilities. The use of a Linear Pulse Tube with its own control unit, both developed by Thales Cryogenics BV, will ensure versatility, reliability and operational flexibility. CCD's will be cooled down to 140K, with stability better than 1K. CCD's will be positioned within 15µm along the optical axis and 50µm in the XY Plan. Slow Control machines will be directly interfaced to an Ethernet network, which will allow them to be operated remotely. The concept of spectrograph leads to a very robust concept without any mechanics (except the shutters). This 30 channels has a impressive compactness with its 3m3 volume. The development of such number of channel will drive to a quasi mass production philosophy.

  12. Spectrographic imaging system

    DOEpatents

    Morris, Michael D.; Treado, Patrick J.

    1991-01-01

    An imaging system for providing spectrographically resolved images. The system incorporates a one-dimensional spatial encoding mask which enables an image to be projected onto a two-dimensional image detector after spectral dispersion of the image. The dimension of the image which is lost due to spectral dispersion on the two-dimensional detector is recovered through employing a reverse transform based on presenting a multiplicity of different spatial encoding patterns to the image. The system is especially adapted for detecting Raman scattering of monochromatic light transmitted through or reflected from physical samples. Preferably, spatial encoding is achieved through the use of Hadamard mask which selectively transmits or blocks portions of the image from the sample being evaluated.

  13. The Cosmic Origins Spectrograph

    NASA Technical Reports Server (NTRS)

    Green, James C.; Froning, Cynthia S.; Osterman, Steve; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Linsky, Jeffrey L.; Savage, Blair D.; Sembach, Kenneth; Shull, J. Michael; Siegmund, Oswald H. W.; Snow, Theodore P.; Spencer, John; Stern, S. Alan; Stocke, John; Welsh, Barry; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin; Keeney, Brian; McPhate, Jason; Penton, Steven V; Andrews, John; Morse, Jon

    2010-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in May 2009, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F(sub lambda) approximates 1.0 X 10(exp -14) ergs/s/cm2/Angstrom, COS can achieve comparable signal to noise (when compared to STIS echelle modes) in 1-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (September 2009 - June 2011) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is 9 times that sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of June 2011. COS has measured, for the first time with high reliability, broad Lya absorbers and Ne VIII in the intergalactic medium, and observed the HeII reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  14. Interferometric resolution boosting for spectrographs

    SciTech Connect

    Erskine, D J; Edelstein, J

    2004-05-25

    Externally dispersed interferometry (EDI) is a technique for enhancing the performance of spectrographs for wide bandwidth high resolution spectroscopy and Doppler radial velocimetry. By placing a small angle-independent interferometer near the slit of a spectrograph, periodic fiducials are embedded on the recorded spectrum. The multiplication of the stellar spectrum times the sinusoidal fiducial net creates a moir{acute e} pattern, which manifests high detailed spectral information heterodyned down to detectably low spatial frequencies. The latter can more accurately survive the blurring, distortions and CCD Nyquist limitations of the spectrograph. Hence lower resolution spectrographs can be used to perform high resolution spectroscopy and radial velocimetry. Previous demonstrations of {approx}2.5x resolution boost used an interferometer having a single fixed delay. We report new data indicating {approx}6x Gaussian resolution boost (140,000 from a spectrograph with 25,000 native resolving power), taken by using multiple exposures at widely different interferometer delays.

  15. Field Raman spectrograph for environmental analysis

    SciTech Connect

    Haas, J.W. III; Forney, R.W.; Carrabba, M.M.; Rauh, R.D.

    1995-12-01

    The enormous cost for chemical analysis at DOE facilities predicates that cost-saving measures be implemented. Many approaches, ranging from increasing laboratory sample throughput by reducing preparation time to the development of field instrumentation, are being explored to meet this need. Because of the presence of radioactive materials at many DOE sites, there is also a need for methods that are safer for site personnel and analysts. This project entails the development of a compact Raman spectrograph for field screening and monitoring of a wide variety of wastes, pollutants, and corrosion products in storage tanks, soils, and ground and surface waters. Analytical advantages of the Raman technique include its ability to produce a unique, spectral fingerprint for each contaminant and its ability to analyze both solids and liquids directly, without the need for isolation or cleanup.

  16. Near ultraviolet spectrograph for balloon platform

    NASA Astrophysics Data System (ADS)

    Sreejith, A. G.; Safonova, Margarita; Murthy, Jayant

    2015-06-01

    Small and compact scientific payloads may be easily designed constructed and own on high altitude balloons. Despite the fact that large orbital observatories provide accurate observations and statistical studies of remote and/or faint space sources, small telescopes on board balloons or rockets are still attractive because of their low cost and rapid response time. We describe here a near ultraviolet (NUV) spectrograph designed to be own on a high{altitude balloon platform. Our basic optical design is a modified Czerny-Turner system using off the shelf optics. We compare different methods of aberration corrections in such a system. We intend the system to be portable and scalable to different telescopes. The use of reflecting optics reduces the transmission loss in UV. We plan on using an image intensified CMOS sensor operating in photon counting mode as the detector of choice.

  17. Moderate-resolution holographic spectrograph

    NASA Astrophysics Data System (ADS)

    Muslimov, E. R.; Pavlycheva, N. K.; Valyavin, G. G.; Fabrika, S. N.

    2016-07-01

    We present a new scheme of a moderate-resolution spectrograph based on a cascade of serial holographic gratings each of which produces an individual spectrum with a resolution of about 6000 and a bandwidth of 80 nm. The gratings ensure centering of each part of the spectrum they produce so as to provide uniform coverage of the broadest possible wavelength interval. In this study we manage to simultaneously cover the 430-680 nm interval without gaps using three gratings. Efficiency of the spectrograph optical system itself from the entrance slit to the CCD detector is typically of about 60% with a maximum of 75%. We discuss the advantages and drawbacks of the new spectrograph scheme as well as the astrophysical tasks for which the instrument can be used.

  18. MMT and Magellan infrared spectrograph

    NASA Astrophysics Data System (ADS)

    McLeod, Brian A.; Fabricant, Daniel; Geary, John; Martini, Paul; Nystrom, George; Elston, Richard; Eikenberry, Stephen S.; Epps, Harland

    2004-09-01

    We present the preliminary design for the MMT and Magellan Infrared Spectrograph (MMIRS). MMIRS is a fully refractive imager and multi-object spectrograph that uses a 2048x2048 pixel Hawaii2 HgCdTe array. It offers a 7'x7' imaging field of view and a 4'x7' field of view for multi-object spectroscopy. Dispersion is provided by a set of 5 grisms providing R=3000 at J, H, or K, or R=1300 in J+H or H+K.

  19. X-ray spectrograph design

    NASA Technical Reports Server (NTRS)

    Chrisp, M. P.

    1983-01-01

    An aberration theory is applied to spectrograph design. The initial system considered has a toroidal mirror in front of a concave grating spectrograph, giving spatial resolution perpendicular to the dispersion direction. The accuracy of the theory is shown by comparison of spot diagrams obtained from the aberrations with those produced by raytracing. The major aberrations affecting the vignetting at the intermediate slit and the spatial resolution are identified. A new system, using a holographic grating to give a flat focal plane, is then designed and optimized. It has increased spatial resolution over the wavelength range and is particularly suitable for microchannel array detectors.

  20. Holographic spectrograph for space telescope

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.; Lysenko, Sergiy; Crenshaw, Melissa

    2013-09-01

    A spectrograph is described which is made with dual Holographic Optical Elements (HOEs) which are identical and parallel to each other. Both optics are collimating transmission HOEs with focal points that are at equal and opposite distances from each other. The identical HOEs are formed by the interference of a plane wave parallel to the grating plane with an off-axis spherical wave originating in the near-field. In playback, a spectrum can be formed from a point source radiator placed at the position of the recording spherical wave. If played back at an arbitrary wavelength other than the recording wavelength, the image exhibits coma. This spectrograph is intended for an unusual configuration where many nearly monochromatic sources of known wavelengths are separately positioned relative to the first HOE. The special application is in a space telescope capable of resolving spectra from habitable planets within 10 pc. HOEs of this type could be fabricated on membrane substrates with a low areal mass and stowable on rolls for insertion into the second Lagrange point. The intended application is for a 50 x 10 meter class primary objective holographic space telescope with 50 x 10 m HOEs in the spectrograph. We present a computer model of the spectrograph.. Experimental results are compared with predictions from theory. A single HOE is shown to perform over a wider bandwidth and is demonstrated.

  1. AVES: an adaptive optics visual echelle spectrograph for the VLT

    NASA Astrophysics Data System (ADS)

    Pasquini, Luca; Delabre, Bernard; Avila, Gerardo; Bonaccini, Domenico

    1998-07-01

    We present the preliminary study of a low cost, high performance spectrograph for the VLT, for observations in the V, R and I bands. This spectrograph is meant for intermediate (R equals 16,000) resolution spectroscopy of faint (sky and/or detector limited) sources, with particular emphasis on the study of solar-type (F-G) stars belonging to the nearest galaxies and to distant (or highly reddened) galactic clusters. The spectrograph is designed to use the adaptive optics (AO) systems at the VLT Telescope. Even if these AO systems will not provide diffraction limited images in the V, R and I bands, the photon concentration will still be above approximately 60% of the flux in an 0.3 arcsecond aperture for typical Paranal conditions. This makes the construction of a compact, cheap and efficient echelle spectrograph possible. AVES will outperform comparable non adaptive optic instruments by more than one magnitude for sky- and/or detector-limited observations, and it will be very suitable for observations in crowded fields.

  2. Texas echelon cross echelle spectrograph

    NASA Astrophysics Data System (ADS)

    Lacy, John H.; Richter, Matthew J.; Yu, Wanglong; Basso, Bianca S.

    1998-08-01

    A new mid-IR spectrograph, the Texas Echelon Cross Echelle Spectrograph (TEXES) is under construction. The primary motivation for TEXES is to observe interstellar molecules at very high resolution. TEXES will operate at 7-25 micrometers wavelength with three spectrographic modes: a high resolution cross-dispersed mode, with R approximately equals 100,000, a mid-resolution long-slit mode, with R approximately equals 14,000, and a low resolution long-slit mode, with R approximately equals 2000. In hi-res mode, the primary disperser is a 36 inch long, R10 grating with a 7 mm groove spacing. The echelon is cross-dispersed with a 7 in long R2 echelle. In mid-res mode, the echelon is by-passed with an Offner relay, and the echelle is used by itself. In lo-res mode, a first-order grating is inserted over the echelle. For initial test, TEXES will use a Hughes Aircraft 20 X 64 pixel Si:As impurity-band array, which covers only two echelon orders. It will later be replaced with a 256 X 256 pixel array, which will Nyquist sample approximately 10 orders. The spectrograph has been assembled and tested with a partially complete echelon, demonstrating the soundness of the design. When we began this project, we were unable to find a vendor capable of machining or ruling a diffraction grating with the very coarse ruling required. Consequently, we attempted to hand-fabricate the echelon. We have not succeeded in assembling the echelon with the required precision, missing by about a factor of two. Fortunately, Hyperfine, Inc. is now capable of diamond machining the echelon. We are purchasing a machined echelon, and hope to complete the spectrograph by the end of summer 1998.

  3. High resolution spectrograph. [for LST

    NASA Technical Reports Server (NTRS)

    Peacock, K.

    1975-01-01

    The high resolution spectrograph (HRS) is designed to be used with the Large Space Telescope (LST) for the study of spectra of point and extended targets in the spectral range 110 to 410 nm. It has spectral resolutions of 1,000; 30,000; and 100,000 and has a field of view as large as 10 arc sec. The spectral range and resolution are selectable using interchangeable optical components and an echelle spectrograph is used to display a cross dispersed spectrum on the photocathode of either of 2 SEC orthicon image tubes. Provisions are included for wavelength calibration, target identification and acquisition and thermal control. The system considerations of the instrument are described.

  4. The AAO's Gemini High-Resolution Optical SpecTrograph (GHOST) concept

    NASA Astrophysics Data System (ADS)

    Ireland, Michael J.; Barnes, Stuart; Cochrane, David; Colless, Matthew; Connor, Peter; Horton, Anthony; Gibson, Steve; Lawrence, Jon; Martell, Sarah; McGregor, Peter; Nicolle, Tom; Nield, Kathryn; Orr, David; Robertson, J. G.; Ryder, Stuart; Sheinis, Andrew; Smith, Greg; Staszak, Nick; Tims, Julia; Xavier, Pascal; Young, Peter; Zheng, Jessica

    2012-09-01

    The Gemini High-Resolution Optical SpecTrograph (GHOST) will fill an important gap in the current suite of Gemini instruments. We will describe the Australian Astronomical Observatory (AAO)-led concept for GHOST, which consists of a multi-object, compact, high-efficiency, fixed-format, fiber-fed design. The spectrograph itself is a four-arm variant of the asymmetric white-pupil echelle Kiwispec spectrograph, Kiwisped, produced by Industrial Research Ltd. This spectrograph has an R4 grating and a 100mm pupil, and separate cross-disperser and camera optics for each of the four arms, carefully optimized for their respective wavelength ranges. We feed this spectrograph with a miniature lensletbased IFU that sub-samples the seeing disk of a single object into 7 hexagonal sub-images, reformatting this into a slit with a second set of double microlenses at the spectrograph entrance with relatively little loss due to focal-ratio degradation. This reformatting enables high spectral resolution from a compact design that fits well within the relatively tight GHOST budget. We will describe our baseline 2-object R~50,000 design with full wavelength coverage from the ultraviolet to the silicon cutoff, as well as the high-resolution single-object R~75,000 mode.

  5. KIDSpec: an MKID based medium resolution integral field spectrograph

    NASA Astrophysics Data System (ADS)

    O'Brien, Kieran; Thatte, Niranjan; Mazin, Benjamin

    2014-07-01

    We present a novel concept for a highly sensitive, medium spectral resolution optical through near-IR spectrograph. KIDSpec, the Kinetic Inductance Detector Spectrograph, uses the intrinsic energy resolving capability of an array of optical/IR-sensitive MKIDs to distinguish multiple orders from a low line-density (echelle) grating. MKID arrays have a wide bandpass (0.1-2.5um) and good quantum efficiency, making them strong candidates for replacing CCDs in many astronomical instruments. By acting as an `order resolver', the MKID array replaces the cross-disperser in an echelle spectrograph. This greatly simplifies the optical layout of the spectrograph and enables longer slits than are possible with cross-dispersed instruments. KIDSpec would have similar capabilities to ESO's X-shooter instrument. It would provide an R=4000-10,000 spectrum covering the entire optical and near-IR spectral range. In addition to a `long-slit' mode, the IFU would provide a small (~50 spaxel) field-of-view for spatially resolved sources. In addition, the photon-counting operation of MKIDs and their photon-energy resolving ability enable a read-noise free spectrum with perfect cosmic ray removal. The spectral resolution would be sufficient to remove the bright night-sky lines without the additional pixel noise, making the instrument more sensitive than an equivalent semiconductor-based instrument. KIDSpec would enhance many existing high-profile science cases, including transient (GRB, SNe, etc.) follow-up, redshift determination of faint objects and transit spectroscopy of exoplanets. In addition it will enable unique science cases, such as dynamical mass estimates of the compact objects in ultra-compact binaries.

  6. EGRAM- ECHELLE SPECTROGRAPH DESIGN AID

    NASA Technical Reports Server (NTRS)

    Dantzler, A. A.

    1994-01-01

    EGRAM aids in the design of spectrographic systems that utilize an echelle-first order cross disperser combination. This optical combination causes a two dimensional echellogram to fall on a detector. EGRAM describes the echellogram with enough detail to allow the user to effectively judge the feasibility of the spectrograph's design. By iteratively altering system parameters, the desired echellogram can be achieved without making a physical model. EGRAM calculates system parameters which are accurate to the first order and compare favorably to results from ray tracing techniques. The spectrographic system modelled by EGRAM consists of an entrance aperture, collimator, echelle, cross dispersion grating, focusing options, and a detector. The system is assumed to be free of aberrations and the echelle, cross disperser, and detector should be planar. The EGRAM program is menu driven and has a HELP facility. The user is prompted for information such as minimum and maximum wavelengths, slit dimensions, ruling frequencies, detector geometry, and angle of incidence. EGRAM calculates the resolving power and range of order numbers covered by the echellogram. A numerical map is also produced. This tabulates the order number, slit bandpass, and high/middle/low wavelengths. EGRAM can also compute the centroid coordinates of a specific wavelength and order (or vice versa). EGRAM is written for interactive execution and is written in Microsoft BASIC A. It has been implemented on an IBM PC series computer operating under DOS. EGRAM was developed in 1985.

  7. The Cosmic Origins Spectrograph: NUV Imaging Performance

    NASA Astrophysics Data System (ADS)

    Goudfrooij, Paul; Burgh, E.; Aloisi, A.; Keyes, C.; Sahnow, D.; Penton, S.; STScI COS Team; COS IDT Team

    2010-01-01

    The Cosmic Origins Spectrograph (COS) includes an NUV imaging mode, which is selected by means of the optical elements MIRRORA or MIRRORB. While the greatest use of this imaging capability is expected to be for target acquisition, science exposures may be obtained as well. COS NUV imaging (with MIRRORA) has specific advantages over other NUV imaging options available on HST, which renders it especially powerful for the purpose of spatially resolving faint, compact, and/or time-variable targets. It features the best spatial sampling available for any imaging mode on HST within its field of view of about 2 arcsec in radius, a much lower dark current rate than the NUV-MAMA detector aboard STIS, and no read noise or charge transfer inefficiency which hamper CCD observations of faint targets in the NUV. This paper reports on the on-orbit calibration of the COS NUV imaging modes, concentrating on accurate measurements of the point spread function, imaging quality, plate scale, photometric zeropoints, and throughput as functions of (a) measurement aperture size and (b) target location within the COS aperture.

  8. The upgraded WIYN bench spectrograph

    NASA Astrophysics Data System (ADS)

    Knezek, Patricia M.; Bershady, Matthew A.; Willmarth, Daryl; Glaspey, John; Poczulp, Gary; Blanco, Dan; Britanik, Lana; McDougall, Eugene; Corson, Charles; Liang, Ming; Keyes, Joe; Jacoby, George

    2010-07-01

    We present the as-built design overview and post-installation performance of the upgraded WIYN Bench Spectrograph. This Bench is currently fed by either of the general-use multi-fiber instruments at the WIYN 3.5m telescope on Kitt Peak, the Hydra multi-object positioner, and the SparsePak integral field unit (IFU). It is very versatile, and can be configured to accommodate low-order, echelle, and volume phase holographic gratings. The overarching goal of the upgrade was to increase the average spectrograph throughput by ~60% while minimizing resolution loss (< 20%). In order to accomplish these goals, the project has had three major thrusts: (1) a new CCD was provided with a nearly constant 30% increase is throughput over 320-1000 nm; (2) two Volume Phase Holographic (VPH) gratings were delivered; and (3) installed a new all-refractive collimator that properly matches the output fiber irradiance (EE90) and optimizes pupil placement. Initial analysis of commissioning data indicates that the total throughput of the system has increased 50-70% using the 600 l/mm surface ruled grating, indicating that the upgrade has achieved its goal. Furthermore, it has been demonstrated that overall image resolution meets the requirement of <20% loss.

  9. Sky subtraction with fiber spectrographs

    NASA Astrophysics Data System (ADS)

    Lissandrini, C.; Cristiani, S.; La Franca, F.

    1994-11-01

    The sky-subtraction performance of multifiber spectrographs is discussed, analyzing in detail the case of the OPTOPUS system at the 3.6-m European Space Observatory (ESO) telescope at La Silla. A standard technique, based on flat fields obtained with a uniformly illuminated screen on the dome, provides poor results. A new method has been developed, using the (O I) emission line at 5577 A as a calibrator of the fiber transmittance, taking into account the diffuse light and the influence of each fiber on the adjacent ones, and correcting for the effects of the image distortions on the sky sampling. In this way the accuracy of the sky subtraction improves from 2%-8% to 1.3%-1.6%.

  10. Ultraviolet-visible spectrograph optics: ODIN project

    NASA Astrophysics Data System (ADS)

    Powell, Ian; Bewsher, Amanda

    1995-10-01

    We describe one of the possible designs for the UV-visible spectrograph optics to be employed in the ODIN project. The spectrograph will be used in a future satellite mission for aeronomy observations and will image a column of atmosphere just above the Earth's surface onto a two-dimensional CCD array with the spatial and spectral content aligned orthogonal to one another.

  11. High-resolving mass spectrographs and spectrometers

    NASA Astrophysics Data System (ADS)

    Wollnik, Hermann

    2015-11-01

    Discussed are different types of high resolving mass spectrographs and spectrometers. In detail outlined are (1) magnetic and electric sector field mass spectrographs, which are the oldest systems, (2) Penning Trap mass spectrographs and spectrometers, which have achieved very high mass-resolving powers, but are technically demanding (3) time-of-flight mass spectrographs using high energy ions passing through accelerator rings, which have also achieved very high mass-resolving powers and are equally technically demanding, (4) linear time-of-flight mass spectrographs, which have become the most versatile mass analyzers for low energy ions, while the even higher performing multi-pass systems have only started to be used, (5) orbitraps, which also have achieved remarkably high mass-resolving powers for low energy ions.

  12. Control of flexure in large astronomical spectrographs

    NASA Astrophysics Data System (ADS)

    D'Arrigo, Paolo

    This thesis describes the design, construction and testing of an experimental system for improving the imaging stability on the detectors of the Intermediate-dispersion Spectroscopic and Imaging System (ISIS), a Cassegrain spectrograph at the 4.2 metre William Hershel Telescope. This system, called ISAAC (ISIS Spectrograph Automatic Active Collimator) is based on the new concept of active compensation, where spectrum shifts, due to the spectrograph flexing under the effect of gravity, are compensated by the movement of an active optical element. ISAAC is a fine steering tip-tilt collimator mirror. The thesis provides an extensive introduction on astronomical spectrographs, active optics and actuator systems. The new concept of active compensation of flexure is also described. The problem of spectrograph flexure is analyzed, focusing in particular on the case of ISIS and on how an active compensation system can help to solve it. The development of ISAAC is explained, from the component specification and design, to the construction and laboratory testing. The performance and successful testing of the instrument at the William Herschel Telescope is then described in detail. The implications for the future of ISIS and of new spectrograph designs are then discussed, with particular stress on the new High Resolution Optical Spectrograph (HROS) for the 8-metre Gemini telescopes.

  13. The Schmidt-Czerny-Turner spectrograph

    NASA Astrophysics Data System (ADS)

    McClure, Jason P.

    2014-09-01

    Since the invention of the CCD detector in 1969 by George Smith and Willard Boyle, incremental innovations to the dispersive imaging spectrograph have slowly materialized in response the abounding advances in CCD detector technology. The modern Czerny-Turner type spectrograph, arguably the most commonly used instrument in optical spectroscopy, fails to uphold the ever increasing needs today's researchers demand, let alone tomorrow's. This paper discusses an innovative solution to the Czerny-Turner imaging spectrograph bridging a more than 20 year gap in development and understanding. A manifold of techniques in optical spectroscopy both advantaged and enabled by this innovation are expounded upon.

  14. On the stability of Cassegrain spectrographs

    NASA Astrophysics Data System (ADS)

    Walker, D. D.; D'Arrigo, P.

    1996-07-01

    Gravity-induced flexure has been a long-standing challenge in Cassegrain spectrographs at 4-m class telescopes; it is more so on the scale of 8-m telescopes. This is of particular concern for the Gemini High Resolution Optical Spectrograph, which will be Cassegrain-mounted for its routine mode of operation. In this paper we address the general flexure problem and make specific recommendations. In a companion paper we present results on experimental compensation for flexure in a specific Cassegrain spectrograph - ISIS on the 4.2-m William Herschel Telescope (WHT).

  15. The Diffuse Interstellar Cloud Experiment: a high-resolution far-ultraviolet spectrograph.

    PubMed

    Schindhelm, Eric; Beasley, Matthew; Burgh, Eric B; Green, James C

    2012-03-01

    We have designed, assembled, and launched a sounding rocket payload to perform high-resolution far-ultraviolet spectroscopy. The instrument is functionally a Cassegrain telescope followed by a modified Rowland spectrograph. The spectrograph was designed to achieve a resolving power (R=λ/δλ) of 60,000 in a compact package by adding a magnifying secondary optic. This is enabled by using a holographically ruled grating to minimize aberrations induced by the second optic. We designed the instrument to observe two stars on opposing sides of a nearby hot/cold gas interface. Obtaining spectra of the O VI doublet in absorption toward these stars can provide new insight into the processes governing hot gas in the local interstellar medium. Here we present the optical design and alignment of the telescope and spectrograph, as well as flight results.

  16. The Diffuse Interstellar Cloud Experiment: a high-resolution far-ultraviolet spectrograph.

    PubMed

    Schindhelm, Eric; Beasley, Matthew; Burgh, Eric B; Green, James C

    2012-03-01

    We have designed, assembled, and launched a sounding rocket payload to perform high-resolution far-ultraviolet spectroscopy. The instrument is functionally a Cassegrain telescope followed by a modified Rowland spectrograph. The spectrograph was designed to achieve a resolving power (R=λ/δλ) of 60,000 in a compact package by adding a magnifying secondary optic. This is enabled by using a holographically ruled grating to minimize aberrations induced by the second optic. We designed the instrument to observe two stars on opposing sides of a nearby hot/cold gas interface. Obtaining spectra of the O VI doublet in absorption toward these stars can provide new insight into the processes governing hot gas in the local interstellar medium. Here we present the optical design and alignment of the telescope and spectrograph, as well as flight results. PMID:22410881

  17. NIR Camera/spectrograph: TEQUILA

    NASA Astrophysics Data System (ADS)

    Ruiz, E.; Sohn, E.; Cruz-Gonzalez, I.; Salas, L.; Parraga, A.; Torres, R.; Perez, M.; Cobos, F.; Tejada, C.; Iriarte, A.

    1998-11-01

    We describe the configuration and operation modes of the IR camera/spectrograph called TEQUILA, based on a 1024X1024 HgCdTe FPA (HAWAII). The optical system will allow three possible modes of operation: direct imaging, low and medium resolution spectroscopy and polarimetry. The basic system is being designed to consist of the following: 1) A LN$_2$ dewar that allocates the FPA together with the preamplifiers and a 24 filter position cylinder. 2) Control and readout electronics based on DSP modules linked to a workstation through fiber optics. 3) An optomechanical assembly cooled to -30oC that provides an efficient operation of the instrument in its various modes. 4) A control module for the moving parts of the instrument. The opto-mechanical assembly will have the necessary provisions to install a scanning Fabry-Perot interferometer and an adaptive optics correction system. The final image acquisition and control of the whole instrument is carried out in a workstation to provide the observer with a friendly environment. The system will operate at the 2.1 m telescope at the Observatorio Astronomico Nacional in San Pedro Martir, B.C. (Mexico), and is intended to be a first-light instrument for the new 7.8 m Mexican Infrared-Optical Telescope (TIM).

  18. Comparison of STIS and SNAP spectrograph throughputs

    SciTech Connect

    Aldering, Greg

    2002-06-30

    This is a comparison of the measured throughput of STIS on HST versus what we might expect from the spectrograph on SNAP. The principle reference is Woodgate et al. (1998) PASP, 110, 1183. Additional material was taken from the STIS Handbook, available on-line at www.stsci.edu. The goal is to demonstrate that there are sound reasons to expect better performance for a SNAP spectrograph (even one with a grating) than would be expected by scaling from HST+STIS.

  19. MEGARA: a new generation optical spectrograph for GTC

    NASA Astrophysics Data System (ADS)

    Gil de Paz, A.; Gallego, J.; Carrasco, E.; Iglesias-Páramo, J.; Cedazo, R.; Vílchez, J. M.; García-Vargas, M. L.; Arrillaga, X.; Carrera, M. A.; Castillo-Morales, A.; Castillo-Domínguez, E.; Eliche-Moral, M. C.; Ferrusca, D.; González-Guardia, E.; Lefort, B.; Maldonado, M.; Marino, R. A.; Martínez-Delgado, I.; Morales Durán, I.; Mujica, E.; Páez, G.; Pascual, S.; Pérez-Calpena, A.; Sánchez-Penim, A.; Sánchez-Blanco, E.; Tulloch, S.; Velázquez, M.; Zamorano, J.; Aguerri, A. L.; Barrado y Naváscues, D.; Bertone, E.; Cardiel, N.; Cava, A.; Cenarro, J.; Chávez, M.; García, M.; Guichard, J.; Gúzman, R.; Herrero, A.; Huélamo, N.; Hughes, D.; Jiménez-Vicente, J.; Kehrig, C.; Márquez, I.; Masegosa, J.; Mayya, Y. D.; Méndez-Abreu, J.; Mollá, M.; Muñoz-Tuñón, C.; Peimbert, M.; Pérez-González, P. G.; Pérez Montero, E.; Rodríguez, M.; Rodríguez-Espinosa, J. M.; Rodríguez-Merino, L.; Rosa-González, D.; Sánchez-Almeida, J.; Sánchez Contreras, C.; Sánchez-Blázquez, P.; Sánchez Moreno, F. M.; Sánchez, S. F.; Sarajedini, A.; Serena, F.; Silich, S.; Simón-Díaz, S.; Tenorio-Tagle, G.; Terlevich, E.; Terlevich, R.; Torres-Peimbert, S.; Trujillo, I.; Tsamis, Y.; Vega, O.; Villar, V.

    2014-07-01

    MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4m telescope in La Palma. MEGARA offers two IFU fiber bundles, one covering 12.5x11.3 arcsec2 with a spaxel size of 0.62 arcsec (Large Compact Bundle; LCB) and another one covering 8.5x6.7 arcsec2 with a spaxel size of 0.42 arcsec (Small Compact Bundle; SCB). The MEGARA MOS mode will allow observing up to 100 objects in a region of 3.5x3.5 arcmin2 around the two IFU bundles. Both the LCB IFU and MOS capabilities of MEGARA will provide intermediate-to-high spectral resolutions (RFWHM~6,000, 12,000 and 18,700, respectively for the low-, mid- and high-resolution Volume Phase Holographic gratings) in the range 3650-9700ÅÅ. These values become RFWHM~7,000, 13,500, and 21,500 when the SCB is used. A mechanism placed at the pseudo-slit position allows exchanging the three observing modes and also acts as focusing mechanism. The spectrograph is a collimator-camera system that has a total of 11 VPHs simultaneously available (out of the 18 VPHs designed and being built) that are placed in the pupil by means of a wheel and an insertion mechanism. The custom-made cryostat hosts an E2V231-84 4kx4k CCD. The UCM (Spain) leads the MEGARA Consortium that also includes INAOE (Mexico), IAA-CSIC (Spain), and UPM (Spain). MEGARA is being developed under a contract between GRANTECAN and UCM. The detailed design, construction and AIV phases are now funded and the instrument should be delivered to GTC before the end of 2016.

  20. NRES: The Network of Robotic Echelle Spectrographs

    NASA Astrophysics Data System (ADS)

    Siverd, Robert; Brown, Timothy M.; Hygelund, John; Henderson, Todd; Tufts, Joseph; Eastman, Jason; Van Eyken, Julian C.; Barnes, Stuart

    2016-01-01

    Las Cumbres Observatory Global Network (LCOGT) is building the Network of Robotic Echelle Spectrographs (NRES), which will consist of six identical, optical (390 - 860 nm) high-precision spectrographs, each fiber-fed simultaneously by up to two 1-meter telescopes and a thorium argon calibration source. We plan to install one at up to 6 observatory sites in the Northern and Southern hemispheres, creating a single, globally-distributed, autonomous spectrograph facility using up to twelve 1-m telescopes. Simulations suggest we will achieve long-term radial velocity precision of 3 m/s in less than an hour for stars brighter than V = 12. We have been funded with NSF MRI and ATI grants, and expect our first spectrograph to be deployed in early 2016, with the full network operation of 5 or 6 units beginning in 2017. We will briefly overview the NRES design, goals, robotic operation, and status. In addition, we will discuss early results from our prototype spectrograph, the laboratory and on-sky performance of our first production unit, and the ongoing software development effort to bring this resource online.

  1. NRES: The Network of Robotic Echelle Spectrographs

    NASA Astrophysics Data System (ADS)

    Siverd, Robert; Brown, Timothy M.; Henderson, Todd; Hygelund, John; Tufts, Joseph; Eastman, Jason; Barnes, Stuart; Van Eyken, Julian C.

    2016-06-01

    Las Cumbres Observatory Global Network (LCOGT) is building the Network of Robotic Echelle Spectrographs (NRES), which will consist of six identical, optical (390 - 860 nm) high-precision spectrographs, each fiber-fed simultaneously by up to two 1-meter telescopes and a thorium argon calibration source. We plan to install one at up to 6 observatory sites in the Northern and Southern hemispheres, creating a single, globally-distributed, autonomous spectrograph facility using up to twelve 1-m telescopes. Simulations suggest we will achieve long-term radial velocity precision of 3 m/s in less than an hour for stars brighter than V = 12. We have been funded with NSF MRI and ATI grants, and expect to deploy the first spectrograph in fall 2016, with the full network operation of 5 or 6 units beginning in 2017. We will briefly overview the NRES design, goals, robotic operation, and status. In addition, we will discuss early results from our prototype spectrograph, the laboratory and on-sky performance of our first production unit, initial science results, and the ongoing software development effort to bring this resource online.

  2. Curved VPH gratings for novel spectrographs

    NASA Astrophysics Data System (ADS)

    Clemens, J. Christopher; O'Donoghue, Darragh; Dunlap, Bart H.

    2014-07-01

    The introduction of volume phase holographic (VPH) gratings into astronomy over a decade ago opened new possibilities for instrument designers. In this paper we describe an extension of VPH grating technology that will have applications in astronomy and beyond: curved VPH gratings. These devices can disperse light while simultaneously correcting aberrations. We have designed and manufactured two different kinds of convex VPH grating prototypes for use in off-axis reflecting spectrographs. One type functions in transmission and the other in reflection, enabling Offnerstyle spectrographs with the high-efficiency and low-cost advantages of VPH gratings. We will discuss the design process and the tools required for modelling these gratings along with the recording layout and process steps required to fabricate them. We will present performance data for the first convex VPH grating produced for an astronomical spectrograph.

  3. An Ultraviolet Imaging Spectrograph for JIMO

    NASA Technical Reports Server (NTRS)

    Hendrix, A. R.; Esposito, L. W.; Pryor, W. R.; Stewart, A. I. F.; McClintock, W. E.; Hansen, C. J.

    2003-01-01

    It is vital to include an ultraviolet spectrograph as part of the JIMO payload to Europa, Ganymede and Callisto. Ultraviolet measurements are key for understanding the atmospheres, auroral activity and surfaces of these icy satellites, and a UV imaging spectrograph will also complement a visible camera and near-IR spectrometer, to achieve full wavelength coverage in remote sensing of the icy satellites. The UV instrument proposed for JIMO will be similar to that currently on board the Cassini spacecraft. The design draws on the experience of building UV spectrometers for Mariner, Pioneer, Galileo and Cassini. It will have three spectrographic channels that provide images and spectra of the atmosphere, aurorae and surface: An EUV channel (800-110 nm), an FUV channel (110 to 190 nm) range, and an NUV channel (180 to 350 nm).

  4. National Student Solar Spectrograph Competition overview

    NASA Astrophysics Data System (ADS)

    Larimer, Randal M.; DesJardins, Angela; Shaw, Joseph A.; Kankelborg, Charles C.; Palmer, Christopher; Springer, Larry; Key, Joey; Knighton, W. Berk; Repasky, Kevin S.; Pust, Nathan J.; Hobish, Mitchell K.; Wilson, Edmond W.; Fitzgerald, Carrie; Fitzgerald, Ryan; Trickel, Thomas; Jensen, Clyde; Dorsett, Skye; Anderson, Matt; Boger, Jim; McCrady, Nate; Naylor, Jaylene; Battle, Laurie

    2012-10-01

    The yearly National Student Solar Spectrograph Competition (NSSSC) is Montana Space Grant Consortium's Education and Public Outreach (EP/O) Program for NASA's Interface Region Imaging Spectrograph (IRIS) mission. The NSSSC is designed to give schools with less aerospace activity such as Minority Serving Institutions and Community Colleges an opportunity for hands on real world research experience. The NSSSC provides students from across the country the opportunity to work as part of an undergraduate interdisciplinary team to design, build and test a ground based solar spectrograph. Over the course of nine months, teams come up with their own science goals and then build an instrument to collect data in support of their goals. Teams then travel to Bozeman, MT to demonstrate their instruments and present their results in a competitive science fair environment. This paper and poster will discuss the 2011-2012 competition along with results as well as provide information on the 2012 -2013 competition opportunities.

  5. Integrating the HERMES spectrograph for the AAT

    NASA Astrophysics Data System (ADS)

    Heijmans, Jeroen; Asplund, Martin; Barden, Sam; Birchall, Michael; Carollo, Daniela; Bland-Hawthorn, Joss; Brzeski, Jurek; Case, Scott; Churilov, Vladimir; Colless, Matthew; Dean, Robert; De Silva, Gayandhi; Farrell, Tony; Fiegert, Kristin; Freeman, Kenneth; Gers, Luke; Goodwin, Michael; Gray, Doug; Heald, Ron; Heng, Anthony; Jones, Damien; Kobayashi, Chiaki; Klauser, Urs; Kondrat, Yuriy; Lawrence, Jon; Lee, Steve; Mathews, Darren; Mayfield, Don; Miziarski, Stan; Monnet, Guy J.; Muller, Rolf; Pai, Naveen; Patterson, Robert; Penny, Ed; Orr, David; Sheinis, Andrew; Shortridge, Keith; Smedley, Scott; Smith, Greg; Stafford, Darren; Staszak, Nicholas; Vuong, Minh; Waller, Lewis; Whittard, Denis; Wylie de Boer, Elisabeth; Xavier, Pascal; Zheng, Jessica; Zhelem, Ross; Zucker, Daniel

    2012-09-01

    The High Efficiency and Resolution Multi Element Spectrograph, HERMES is an optical spectrograph designed primarily for the GALAH, Galactic Archeology Survey, the first major attempt to create a detailed understanding of galaxy formation and evolution by studying the history of our own galaxy, the Milky Way1. The goal of the GALAH survey is to reconstruct the mass assembly history of the of the Milky way, through a detailed spatially tagged abundance study of one million stars in the Milky Way. The spectrograph will be based at the Anglo Australian Telescope (AAT) and be fed with the existing 2dF robotic fibre positioning system. The spectrograph uses VPH-gratings to achieve a spectral resolving power of 28,000 in standard mode and also provides a high resolution mode ranging between 40,000 to 50,000 using a slit mask. The GALAH survey requires a SNR greater than 100 aiming for a star brightness of V=14. The total spectral coverage of the four channels is about 100nm between 370 and 1000nm for up to 392 simultaneous targets within the 2 degree field of view. Current efforts are focused on manufacturing and integration. The delivery date of spectrograph at the telescope is scheduled for 2013. A performance prediction is presented and a complete overview of the status of the HERMES spectrograph is given. This paper details the following specific topics: The approach to AIT, the manufacturing and integration of the large mechanical frame, the opto-mechanical slit assembly, collimator optics and cameras, VPH gratings, cryostats, fibre cable assembly, instrument control hardware and software, data reduction.

  6. VIRUS spectrograph assembly and alignment procedures

    NASA Astrophysics Data System (ADS)

    Prochaska, Travis; Allen, Richard D.; Boster, Emily; DePoy, D. L.; Herbig, Benjamin; Hill, Gary J.; Lee, Hanshin; Marshall, Jennifer L.; Martin, Emily C.; Meador, William; Rheault, Jean-Philippe; Tuttle, Sarah E.; Vattiat, Brian L.

    2012-09-01

    We describe the mechanical assembly and optical alignment processes used to construct the Visual Integral-Field Replicable Unit Spectrograph (VIRUS) instrument. VIRUS is a set of 150+ optical spectrographs designed to support observations for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). To meet the instrument's manufacturing constraints, a production line will be set up to build subassemblies in parallel. To aid in the instrument's assembly and alignment, specialized fixtures and adjustment apparatuses have been developed. We describe the design and operations of the various optics alignment apparatuses, as well as the mirrors' alignment and bonding fixtures.

  7. Initial results from VIRUS production spectrographs

    NASA Astrophysics Data System (ADS)

    Tuttle, Sarah E.; Allen, Richard D.; Chonis, Taylor S.; Cornell, Mark E.; DePoy, Darren L.; Hill, Gary J.; Lee, Hanshin; Marshall, Jennifer L.; Prochaska, Travis; Rafal, Marc D.; Savage, Richard D.; Vattiat, Brian L.

    2012-09-01

    The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) uses a novel technique of replicated spectrographs (VIRUS) to measure dark energy at intermediate redshifts (2 < z < 4). VIRUS contains over 30,000 fibers and over 160 independent and identical channels. Here we report on the construction and characterization of the initial batch of VIRUS spectrograph cameras. Assembly of the first batch of 16 is in progress. A brief overview of the assembly is presented, and where available performance is compared to specification.

  8. HETDEX: VIRUS Spectrographs Assembly and Alignment

    NASA Astrophysics Data System (ADS)

    Prochaska, Travis; Marshall, J. L.; DePoy, D. L.; Boster, E.; Meador, W.; Allen, R.; Hill, G. J.; HETDEX Collaboration

    2012-01-01

    We describe the assembly and optical alignment process used to construct the Visual Integral-Field Replicable Unit Spectrograph (VIRUS) instrument. VIRUS is a set of 150+ optical spectrographs designed to support observations for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). To meet the accuracy, interchangeability, time and cost constraints, a production line will be set up to construct and test modular subassemblies in parallel. To facilitate the VIRUS production, fixtures and adjustment mechanisms have been designed to aid in assembly and alignment. This poster describes the details and operations of the camera mirror, collimator mirror and grating adjustment mechanisms, as well as the fold flat mirror alignment fixture.

  9. Spectrographic analysis of coal and coal ash

    USGS Publications Warehouse

    Hunter, R.G.; Headlee, A.J.W.

    1950-01-01

    Coal can be analyzed on the spectrograph for per cent ash and composition of ash in a matter of a few minutes, using the total energy method. The composition of the ash so determined can be used to calculate ash softening temperatures. This analysis can be made in sufficiently short a time to control tipple and washing operations for preparation of coal to meet specifications. This spectrographic method can be readily adapted to the analysis of rocks, minerals, and inorganic chemicals of all kinds.

  10. Upgrade Of The SDSS Spectrographs For BOSS

    NASA Astrophysics Data System (ADS)

    Roe, Natalie; Barkhouser, R.; Carey, L.; Carr, M.; Eisenstein, D. J.; Gunn, J. E.; Honscheid, K.; Leger, F.; Rockosi, C.; Schlegel, D. J.; Smee, S.

    2010-01-01

    A major upgrade of the Sloan Digital Sky Survey (SDSS) fiber-fed spectrographs was completed in August, 2009. The upgraded spectrographs have 50% more fibers, extended wavelength coverage and much improved throughput. Large format VPH gratings and thick, fully-depleted CCDs are special features of the upgrade, which will enable the Baryon Oscillation Spectroscopic Survey (BOSS) project to obtain spectra of 1.4M galaxies and 160,000 quasars in five years of dark time observations. We report on the details of the upgrade, including the fiber system, optics, cameras and electronics.

  11. Mass producing an efficient NIR spectrograph

    NASA Astrophysics Data System (ADS)

    Wilson, John C.; Henderson, Charles P.; Herter, Terry L.; Matthews, Keith; Skrutskie, Michael F.; Adams, Joseph D.; Moon, Dae-Sik; Smith, Roger; Gautier, Nick; Ressler, Michael; Soifer, B. T.; Lin, Sean; Howard, James; LaMarr, John; Stolberg, Todd M.; Zink, Jeff

    2004-09-01

    Four institutions are collaborating to design and build three near identical R ~2700 cross-dispersed near-infrared spectrographs for use on various 5-10 meter telescopes. The instrument design addresses the common observatory need for efficient, reliable near-infrared spectrographs through such features as broad wavelength coverage across 6 simultaneous orders (0.8 - 2.4 microns) in echelle format, real-time slit viewing through separate optics and detector, and minimal moving parts. Lastly, the collaborators are saving money and increasing the likelihood of success through economies of scale and sharing intellectual capital.

  12. The Spartan-281 Far Ultraviolet Imaging Spectrograph

    NASA Technical Reports Server (NTRS)

    Carruthers, George R.; Heckathorn, Harry M.; Dufour, Reginald J.; Opal, Chet B.; Raymond, John C.

    1988-01-01

    The U.S. Naval Research Laboratory's Far Ultraviolet Imaging Spectrograph (FUVIS), currently under development for flight as a Spartan shuttle payload, is designed to perform spectroscopy of diffuse sources in the FUV with very high sensitivity and moderate spatial and spectral resolution. Diffuse nebulae, the general galactic background radiation, and artificially induced radiation associated with the Space Shuttle vehicle are sources of particular interest. The FUVIS instrument will cover the wavelength range of 970-2000 A with selectable resolutions of 5 and 30 A. It is a slit imaging spectrograph having 3 arcmin spatial resolution along its 2.7 deg long slit.

  13. The optical design of MARVELS spectrograph

    NASA Astrophysics Data System (ADS)

    Zhao, Bo; Ge, Jian; Groot, John

    2009-08-01

    This paper describes an optical spectrograph design for the Multi-object APO Radial-Velocity Exoplanet Large-area Survey (MARVELS) instrument. This MARVELS instrument is currently installed at the Sloan 2.5m telescope, and is capable of simultaneously monitoring 60 stars at high radial velocity precision for a planet survey. The MARVELS spectrograph consists of an entrance slit (multi-slits), collimator optics, a Volume Phase Holographic (VPH) grating, camera optics and a 4kx4k CCD camera, which with a 160mm diameter collimated beam provides a spectral resolution of R =10000. This spectrograph is transmissive and optimized for delivering high throughput and high image quality over the entire operation bandwidth 500-570nm and the whole 160mmx30mm square shape FOV. The collimator and camera optics (280 mm largest diameter) are all made of standard optical grade glasses. The f/4 input beams from the MARVELS monolithic interferometer are converted to f/1.5 beams on the detector by this spectrograph, and form 120 stellar fringe spectra.

  14. VXMS: the VISTA extreme multiplex spectrograph

    NASA Astrophysics Data System (ADS)

    Content, Robert; Shanks, Tom; Sharples, Ray; Bramall, David; Percival, Will

    2012-09-01

    A study for a spectrograph delivering at least 10000 slits for galaxies and 20000 for stars over a 2.5 deg2 field have been completed as an answer to the call for proposal for future VISTA MOS instrumentation. In a single night, 65000 galaxy redshifts can be measured to z~0.7 and beyond for measuring the Baryon Acoustic Oscillation (BAO) scale and many other science goals. The design features ten cloned spectrographs which give a smaller total weight and length than a unique spectrograph to make it placable in the space envelope of the Cassegrain focus. The clones use a transparent design including a grism in which all optics are about the size or smaller than the clone rectangular subfield so that they can be tightly packed with little gaps between subfields. Only low cost glasses are used; the variations in chromatic aberrations between bands are compensated by changing a box containing the grism and two adjacent lenses. Two bands cover the 550nm to 900nm wavelength range at resolution of 1100 for blue end and 3000 for red end while another cover the Calcium triplet at 5000. An optional box does imaging but we studied different innovative methods for acquisition without imaging. A new 2.3° corrector was designed that places the pupil before and relatively near the focal plane which permits to give more space at the back of the spectrographs by placing them in a hedgehog configuration. An offaxis field lens in each spectrograph permits to control the pupil position.

  15. Spectrographs for the Measurement of Radial Velocities

    NASA Astrophysics Data System (ADS)

    Baranne, A.

    A radial-velocity measurement derives from a shift in position of spectral features at the focus of a spectrographic instrument. We do not often think about how small these shifts are. It is not generally appreciated that the accuracy to which this shift must be measured is a tiny fraction of a pixel. Or, if we prefer to calculate in microns a surprising minuteness. What precautions should we be taking for the measurement of such small shifts? It is true that, thanks to computers, modern reduction methods allows us to correct for a wide variety of pertubations, provided that these are foreseen and understood; but such reduction procedures will give the best results if such pertubations are kept very small. We must therefore analyse these pertubations and think about how we can control them. The correlation method initiated in its modern form by Roger Griffin, and which we developed further with an optical mask in CORAVEL twenty-five years ago and more recently with a numerical mask in ELODIE, has demonstrated its power. In terms of these methods, the problem of high precision is to improve the correlation peak. Can this be done? Does the correlation method allow us to distinguish the overall radial velocity of the object from possible distortions of the lines? This is certainly a major problem which must be solved. The luminous efficiency of high-precision spectrographs is low. If the use of an optical fibre with scrambling for feeding the spectrograph seems inevitable to us today, it seems to me that the transmission of this system can be considerably improved by a better choice of the F-ratio of the image beam of the telescope which is to be matched with that of the spectrograph. This problem, common to all spectrographs, could be resolved with a specialised focal-plane instrument, giving a much greater than usual F-ratio, resulting in a simplification of the spectrograph optics, and hence an improvement in transmission and a serious decrease in size (which is

  16. HETDEX: Optical Alignment Of The Virus Spectrographs

    NASA Astrophysics Data System (ADS)

    Martin, Emily; Marshall, J.; Rheault, J.; DePoy, D.; Prochaska, T.; Allen, R.; Hill, G.; HETDEX Collaboration

    2012-01-01

    We present an optical alignment procedure for the Visible Integral-Field Replicable Unit Spectrograph (VIRUS) collimator. Texas A&M is helping to build the VIRUS spectrographs, designed in collaboration with The University of Texas at Austin. The Hobby Eberly Telescope Dark Energy Experiment (HETDEX) will use as many as 192 units of this instrument to search for answers regarding Dark Energy. Texas A&M is currently assembling the collimators for VIRUS and designing alignment fixtures to aid in the assembly. We used ZEMAX models of VIRUS optics made by UT engineers to analyze various alignment methods we have considered. Our current plan uses two steps to properly align the collimator within the tolerance of 0.1-degrees. This will permit interchangeability among the various VIRUS parts.

  17. WAVELENGTH CALIBRATION OF THE HAMILTON ECHELLE SPECTROGRAPH

    SciTech Connect

    Pakhomov, Yu. V.; Zhao, G.

    2013-10-01

    We present the wavelength calibration of the Hamilton Echelle Spectrograph at Lick Observatory. The main problem with the calibration of this spectrograph arises from the fact that thorium lines are absent in the spectrum of the presumed ThAr hollow-cathode lamp now under operation; numerous unknown strong lines, which have been identified as titanium lines, are present in the spectrum. We estimate the temperature of the lamp's gas which permits us to calculate the intensities of the lines and to select a large number of relevant Ti I and Ti II lines. The resulting titanium line list for the Lick hollow-cathode lamp is presented. The wavelength calibration using this line list was made with an accuracy of about 0.006 Å.

  18. Multiple object spectroscopy - The Medusa spectrograph

    NASA Technical Reports Server (NTRS)

    Hill, J. M.; Angel, J. R. P.; Scott, J. S.; Lindley, D.; Hintzen, P.

    1980-01-01

    An instrument has been built to obtain simultaneous spectra of many objects in the field of view of the Steward 90 inch (2.29 m) telescope. Short lengths of fused silica fiber 300 microns in diameter are used to bring the light from galaxy images at the Cassegrain focus into a line along the spectrograph slit. From a single exposure of the cluster Abell 1904, which has a redshift of 20,000 km/s, the redshifts of 26 individual galaxies were determined, each with a precision of 100 km/s. The present device, while already giving a sixfold reduction in the mean telescope time per galaxy, has significant light losses because it is not ideally matched to the telescope. An instrument being designed for the prime focus will transmit light from each object as efficiently as a conventional spectrograph.

  19. Faint-object spectrograph optical bench

    NASA Technical Reports Server (NTRS)

    Toth, J. M., Jr.; Lyon, R. L.

    1982-01-01

    The Faint-Object Spectrograph (FOS) is one of five scientific instruments under development for use with the Optical Telescope Assembly (OTA) of NASA's Space Telescope. It is a dual-channel spectrograph operating with two independent 512-channel pulse-counting Digicons. The FOS will be employed in connection with the study of scientific questions associated with quasars, active galaxies, normal distant and local group galaxies, a wide class of objects within the Milky Way Galaxy and neighboring galaxies, and objects within the solar system. The FOS contains an optical bench which supports all optical elements. Dimensional stability was the primary design requirement for the optical bench. This led to the selection of a graphite/epoxy structure using laminates with very low coefficients of thermal expansion and high stiffness. The technical requirements are considered and details of fabrication are discussed.

  20. The design of the WEAVE spectrograph

    NASA Astrophysics Data System (ADS)

    Rogers, Kevin; Stuik, Remko; Steele, Iain A.; Pragt, Johan; Middleton, Kevin F.; Bates, Stuart; Kragt, Jan; Tromp, Niels; Lesman, Dirk; Lhomé, Emilie; Dalton, Gavin; Trager, Scott; Navarro, Ramon; Abrams, Don C.; Tosh, Ian; Jasko, Attila; Martin, Carlos; O'Mahony, Neil; Pico, Sergio; Cano Infantes, Diego; Bianca, Andrea; Delgado, Jose; Rodríguez, Luis F.

    2014-07-01

    WEAVE is the next-generation optical spectroscopy facility for the William Herschel Telescope and aims at spectroscopic follow-up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE places in the re-fitted prime focus either 1000 fibres, 20 fibre-coupled mini-IFUs or a single large 600 fibre IFU. A spectrograph on the Nasmyth platform analyses the light and supports, in a single exposure, either R~5,000 observations over the full 366- 975 nm wavelength range or simultaneous R~20,000 observations over two out of three pre-specified bands within this wavelength range. This paper describes the requirements, optical design and mechanical design of the WEAVE spectrograph.

  1. User Support for the HST Spectrographs

    NASA Astrophysics Data System (ADS)

    Gonnella, A. M.; Christensen, J. A.; Hulbert, S. J.

    1997-12-01

    Plans for user support of the HST spectrographs include the two archival instruments, GHRS and FOS, as well as the currently operational STIS. Support for users of STIS covers the range of proposal preparation, calibration and visits to the institute, whereas support for the archival instruments is not as broad. We describe the ways in which an observer can find support through our extensive World Wide Web resources and the Space Telescope help desk.

  2. Integrating TV/digital data spectrograph system

    NASA Technical Reports Server (NTRS)

    Duncan, B. J.; Fay, T. D.; Miller, E. R.; Wamsteker, W.; Brown, R. M.; Neely, P. L.

    1975-01-01

    A 25-mm vidicon camera was previously modified to allow operation in an integration mode for low-light-level astronomical work. The camera was then mated to a low-dispersion spectrograph for obtaining spectral information in the 400 to 750 nm range. A high speed digital video image system was utilized to digitize the analog video signal, place the information directly into computer-type memory, and record data on digital magnetic tape for permanent storage and subsequent analysis.

  3. Spectrograph Measures Contamination Of Optical Elements

    NASA Technical Reports Server (NTRS)

    Flint, Bruce K.; Fancy, Robert D.; Jarratt, Robert V., Jr.

    1989-01-01

    Scanning-monochromator spectrograph designed to measure contamination on surfaces of optical elements as function of time. Repeatedly exposes samples to environment, then measures their transmittances or reflectances over range of wavelengths. Intended for use at vacuum-ultraviolet wavelengths to evaluate effects of outgassing, heating, and cooling on optical instruments. Principle of operation also applicable to spectral monitoring of time-dependent contamination at other wavelengths and in laboratory, industrial, or other settings.

  4. Early Doppler Performance from New Generation High Resolution Optical and near Infrared Planet-hunting Spectrographs

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Varosi, F.; Powell, S.; Zhao, B.; Schofield, S.; Liu, J.; Warner, C.; Sithajan, S.; Li, R.; Muterspaugh, M. W.; Williamson, M. W.; Avner, L.; Jakeman, H.

    2014-01-01

    The next generation of radial velocity (RV) planet surveys require high precision (sub m/s for optical and 1-3 m/s for near infrared (NIR)) and high cadence 100 RV measurements per star) to systematically reach low mass planet populations, including habitable Earth-like planets, around FGKM dwarfs and study their properties. These require new sensitive optical and NIR high resolution spectrographs. At UF, we have developed two new generation optical and NIR high resolution spectrographs for high precision RV low mass planet surveys. The optical high resolution spectrograph called EXtremely high Precision ExtrasolaR planet Tracker (EXPERT) III (EXPERT-III), was commissioned at the Automatic Spectroscopic Telescope (AST), a robotic telescope at Fairborn Observatory in Arizona in July 2013 and has produced a spectral resolution of about 100,000 and a simultaneous wavelength coverage of 0.38-0.9 mm with a 4kx4k back-illuminated Fairchild CCD detector. The early RV measurements show that this instrument has reached ~0.7 m/s RV precision and daily instrument stability is better than 5m/s. The near IR spectrograph, called the Florida IR Silicon immersion grating spectromeTer (FIRST), has produced 60,000 at 0.8-1.8 microns with a 2kx2k H2RG IR array. FIRST is the first high resolution NIR spectrograph taking full advantage of an innovative silicon immersion grating to achieve high spectral resolution (3.4 times higher than a commercially available echelle grating of the equal size and blaze angle) in an extremely compact design. FIRST is schedule to be commissioned at AST in October 2013. Here we report on-sky RV performance and early science results from the AST robotic observations.

  5. Optical design of a versatile FIRST high-resolution near-IR spectrograph

    NASA Astrophysics Data System (ADS)

    Zhao, Bo; Ge, Jian

    2012-09-01

    We report the update optical design of a versatile FIRST high resolution near IR spectrograph, which is called Florida IR Silicon immersion grating spectromeTer (FIRST). This spectrograph uses cross-dispersed echelle design with white pupils and also takes advantage of the image slicing to increase the spectra resolution, while maintaining the instrument throughput. It is an extremely high dispersion R1.4 (blazed angle of 54.74°) silicon immersion grating with a 49 mm diameter pupil is used as the main disperser at 1.4μm -1.8μm to produce R=72,000 while an R4 echelle with the same pupil diameter produces R=60,000 at 0.8μm -1.35μm. Two cryogenic Volume Phase Holographic (VPH) gratings are used as cross-dispersers to allow simultaneous wavelength coverage of 0.8μm -1.8μm. The butterfly mirrors and dichroic beamsplitters make a compact folding system to record these two wavelength bands with a 2kx2k H2RG array in a single exposure. By inserting a mirror before the grating disperser (the SIG and the echelle), this spectrograph becomes a very efficient integral field 3-D imaging spectrograph with R=2,000-4,000 at 0.8μm-1.8μm by coupling a 10x10 telescope fiber bundle with the spectrograph. Details about the optical design and performance are reported.

  6. 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.

  7. An Opto-MEMS Multiobject Spectrograph

    NASA Astrophysics Data System (ADS)

    Kearney, K.; Ninkov, Z.; Zwarg, D.

    2000-05-01

    Optical MEMS (Micro-Electro-Mechanical-Structures) are an enabling technology for a new class of optical instrumentation designs. An opto-MEMS device consists of an array of microfabricated structures, each of which modulates the phase and/or amplitude of an incident light beam. Typically the devices consist of an array of moveable micromirrors - each of which reflects an incident beam in a unique direction (tilt), or with a unique phase shift (piston). One widely available opto-MEMS device is the Texas Instruments' Digital Micromirror Device (DMD). The DMD is an array of 16 micron x 16 micron square mirrors postioned on a 17 micron pitch. Each mirror can tilt +/- 10 degrees from the normal - reflecting a normally incident light beam +/- 20 degrees. By positioning the DMD in an intermediate image plane in an optical system, portions of the image can be directed into- or out-of the input pupil of the follow-on imaging optics. RIT is utilizing the DMD to construct a prototype multiobject spectrograph (RIT-MOS) for visible observations with terrestrial telescopes. The DMD array replaces the input slit of an imaging spectrograph, forming a 'virtual', programmable slit assembly. By acquiring a pre-image of the astronomical field, it is possible to select a multidude of objects, and to program the DMD to pass only those objects into the input optics of the imaging spectrograph. We will report on the design and characterizatotion of the RIT-MOS, as well as preliminary imaging results.

  8. VIBRATION COMPACTION

    DOEpatents

    Hauth, J.J.

    1962-07-01

    A method of compacting a powder in a metal container is described including the steps of vibrating the container at above and below the resonant frequency and also sweeping the frequency of vibration across the resonant frequency several times thereby following the change in resonant frequency caused by compaction of the powder. (AEC)

  9. PRAXIS: low thermal emission high efficiency OH suppressed fibre spectrograph

    NASA Astrophysics Data System (ADS)

    Content, Robert; Bland-Hawthorn, Joss; Ellis, Simon; Gers, Luke; Haynes, Roger; Horton, Anthony; Lawrence, Jon; Leon-Saval, Sergio; Lindley, Emma; Min, Seong-Sik; Shortridge, Keith; Staszak, Nick; Trinh, Christopher; Xavier, Pascal; Zhelem, Ross

    2014-07-01

    PRAXIS is a second generation instrument that follows on from GNOSIS, which was the first instrument using fibre Bragg gratings for OH suppression to be deployed on a telescope. The Bragg gratings reflect the NIR OH lines while being transparent to the light between the lines. This gives in principle a much higher signal-noise ratio at low resolution spectroscopy but also at higher resolutions by removing the scattered wings of the OH lines. The specifications call for high throughput and very low thermal and detector noise so that PRAXIS will remain sky noise limited even with the low sky background levels remaining after OH suppression. The optical and mechanical designs are presented. The optical train starts with fore-optics that image the telescope focal plane on an IFU which has 19 hexagonal microlenses each feeding a multi-mode fibre. Seven of these fibres are attached to a fibre Bragg grating OH suppression system while the others are reference/acquisition fibres. The light from each of the seven OH suppression fibres is then split by a photonic lantern into many single mode fibres where the Bragg gratings are imprinted. Another lantern recombines the light from the single mode fibres into a multi-mode fibre. A trade-off was made in the design of the IFU between field of view and transmission to maximize the signal-noise ratio for observations of faint, compact objects under typical seeing. GNOSIS used the pre-existing IRIS2 spectrograph while PRAXIS will use a new spectrograph specifically designed for the fibre Bragg grating OH suppression and optimised for 1.47 μm to 1.7 μm (it can also be used in the 1.09 μm to 1.26 μm band by changing the grating and refocussing). This results in a significantly higher transmission due to high efficiency coatings, a VPH grating at low incident angle and optimized for our small bandwidth, and low absorption glasses. The detector noise will also be lower thanks to the use of a current generation HAWAII-2RG detector

  10. Upgrade of the area II spectrograph

    SciTech Connect

    Rehm, K.E.; Bolduc, C.

    1995-08-01

    Because of the low beam energies required for experiments of astrophysical interest, the first test experiments with radioactive {sup 18}F beams can be performed in Area II. Because of the shorter distances between ion source and detector this also results in higher transmission efficiencies. The Enge split-pole spectrograph, which was not used during the last 8 years, was equipped with a new cryopump system, upgrades to the magnet power supply and the NMR system were performed. A rotating target system was built which should alleviate target deterioration effects that were observed in first test experiments.

  11. New soft x-ray emission spectrograph

    NASA Astrophysics Data System (ADS)

    Carson, R. D.; Franck, C. P.; Schnatterly, S.; Zutavern, F.

    1984-12-01

    We have built a new soft x-ray emission spectrograph covering the photon energy range 20-800 eV. It incorporates toroidal holographic grazing incidence diffraction gratings and a position-sensitive photodiode array as a detector. The detector electronics are remote from the array which is under vacuum at nitrogen temperature, and features a double-correlated sampling scheme. The sample is excited with a Pierce-type electron gun using a quadrupole focusing lens. The performance of the instrument is described.

  12. Exact optics - III. Schwarzschild's spectrograph camera revised

    NASA Astrophysics Data System (ADS)

    Willstrop, R. V.

    2004-03-01

    Karl Schwarzschild identified a system of two mirrors, each defined by conic sections, free of third-order spherical aberration, coma and astigmatism, and with a flat focal surface. He considered it impractical, because the field was too restricted. This system was rediscovered as a quadratic approximation to one of Lynden-Bell's `exact optics' designs which have wider fields. Thus the `exact optics' version has a moderate but useful field, with excellent definition, suitable for a spectrograph camera. The mirrors are strongly aspheric in both the Schwarzschild design and the exact optics version.

  13. Instrumental profile of the Debrecen solar spectrograph

    NASA Astrophysics Data System (ADS)

    Murakozy, J.; Vince, I.; Ludmany, A.

    The solar spectrograph of the Heliophysical Observatory at Debrecen, Hungary, was investigated to determine its instrumental profile. The measurements were made by using a HeNe laser beam. The widths and asymmetries of the profiles decrease toward higher spectral orders, the most advantageous orders being the third and the fourth ones. To eliminate the broadening of solar lines on account of the instrumental profile, the straightforward iteration method of Gurtovenko has been applied. The efficiency of the method is demonstrated by the simulation of the broadened and corrected spectral line profiles.

  14. Advanced prism-grating-prism imaging spectrograph in online industrial applications

    NASA Astrophysics Data System (ADS)

    Vaarala, Tapio; Aikio, Mauri; Keraenen, Heimo

    1997-08-01

    Imaging spectrographs have traditionally been utilized in aerial and remote sensing applications. A novel, compact and inexpensive imaging spectrograph developed by VTT Electronics is now available. It contains a multichannel fiber optic sensor head, a dispersive prism-grating-prism (PGP) component and digital CCD matrix camera capable of area integration. In rolled steel manufacturing, a protective oil film is applied on steel to resist corrosion while in transport and storage. The main problems in the oiling machine are film thickness control and jet failures. In this application, the spectrum of fluorescence of an oil film was measured simultaneously with parallel fibers. A relatively simple calibration and analysis procedure was used to calculate the oil film thickness. On-line color control for color reproduction is essential in both consumer and industrial products. The instrument was tested and analyzed for measuring differences in color by multivariate analysis of the spectra and by color space coordinate estimation. In general, a continuous spectrum is not absolute requirement. In these two examples, filter-based measurement would probably cost less thana PGP spectrograph solution. On the other hand, by measuring the spectrum and using an advanced signal processing algorithm one production version will cover all installations in both applications. In practice, only the fiber sensor mechanics need to be modified.

  15. LRS2: A New Integral Field Spectrograph for the HET

    NASA Astrophysics Data System (ADS)

    Tuttle, Sarah E.; Hill, Gary J.; Chonis, Taylor S.; Tonnesen, Stephanie

    2016-01-01

    Here we present LRS2 (Low Resolution Spectrograph) and highlight early science opportunities with the newly upgraded Hobby Eberly telescope (HET). LRS2 is a four-channel optical wavelength (370nm - 1micron) spectrograph based on two VIRUS unit spectrographs. This fiber-fed integral field spectrograph covers a 12" x 6" field of view, switched between the two units (one blue, and one red) at R~2000. We highlight design elements, including the fundamental modification to grisms (from VPH gratings in VIRUS) to access the higher resolution. We discuss early science opportunities, including investigating nearby "blue-bulge" spiral galaxies and their anomalous star formation distribution.

  16. The deterministic optical alignment of the HERMES spectrograph

    NASA Astrophysics Data System (ADS)

    Gers, Luke; Staszak, Nicholas

    2014-07-01

    The High Efficiency and Resolution Multi Element Spectrograph (HERMES) is a four channel, VPH-grating spectrograph fed by two 400 fiber slit assemblies whose construction and commissioning has now been completed at the Anglo Australian Telescope (AAT). The size, weight, complexity, and scheduling constraints of the system necessitated that a fully integrated, deterministic, opto-mechanical alignment system be designed into the spectrograph before it was manufactured. This paper presents the principles about which the system was assembled and aligned, including the equipment and the metrology methods employed to complete the spectrograph integration.

  17. The Faulkes Telescope Optical Spectrographs and Swift

    NASA Astrophysics Data System (ADS)

    O'Brien, Paul

    The Faulkes Telescope project funded primarily by the Dill Faulkes Educational Trust is currently constructing two 2-m robotic telescopes to be located in Hawaii and Australia. These will be the largest and most powerful telescopes ever built dedicated for use by schools and colleges. We have been awarded funding to build two optical spectrographs to be permanently mounted on these telescopes by the end of 2003. At this time an astronomical satellite called Swift will be launched by NASA. Swift is dedicated to the study of gamma-ray bursts the most powerful explosive events in the Universe. The Department of Physics and Astronomy at the University of Leicester has provided the X-ray camera for Swift and is a partner in the Faulkes Telescopes project. To enhance both projects we intend to use the Faulkes Telescope optical spectrographs to study the gamma-ray bursts identified by Swift. These data will also be made available to schools thereby raising the profile of physics and astronomy in the educational community.

  18. Field Raman Spectrograph for Environmental Analysis

    SciTech Connect

    Sylvia, J.M.; Haas, J.W.; Spencer, K.M.; Carrabba, M.M.; Rauh, R.D.; Forney, R.W.; Johnston, T.M.

    1998-07-01

    The widespread contamination found across the US Department of Energy (DOE) complex has received considerable attention from the government and public alike. A massive site characterization and cleanup effort has been underway for several years and is expected to continue for several decades more. The scope of the cleanup effort ranges from soil excavation and treatment to complete dismantling and decontamination of whole buildings. To its credit, DOE has supported research and development of new technologies to speed up and reduce the cost of this effort. One area in particular has been the development of portable instrumentation that can be used to perform analytical measurements in the field. This approach provides timely data to decision makers and eliminates the expense, delays, and uncertainties of sample preservation, transport, storage, and laboratory analysis. In this program, we have developed and demonstrated in the field a transportable, high performance Raman spectrograph that can be used to detect and identify contaminants in a variety of scenarios. With no moving parts, the spectrograph is rugged and can perform many Raman measurements in situ with flexible fiber optic sampling probes. The instrument operates under computer control and a software package has been developed to collect and process spectral data. A collection of Raman spectra for 200 contaminants of DOE importance has been compiled in a searchable format to assist in the identification of unknown contaminants in the field.

  19. LOTUS: a low-cost, ultraviolet spectrograph

    NASA Astrophysics Data System (ADS)

    Steele, I. A.; Marchant, J. M.; Jermak, H. E.; Barnsley, R. M.; Bates, S. D.; Clay, N. R.; Fitzsimmons, A.; Jehin, E.; Jones, G.; Mottram, C. J.; Smith, R. J.; Snodgrass, C.; de Val-Borro, M.

    2016-08-01

    We describe the design, construction and commissioning of a simple, low-cost long-slit spectrograph for the Liverpool Telescope. The design is optimized for near-UV and visible wavelengths and uses all transmitting optics. It exploits the instrument focal plane field curvature to partially correct axial chromatic aberration. A stepped slit provides narrow (2.5 × 95 arcsec) and wide (5 × 25 arcsec) options that are optimized for spectral resolution and flux calibration, respectively. On sky testing shows a wavelength range of 3200-6300 Å with a peak system throughput (including detector quantum efficiency) of 15 per cent and wavelength dependent spectral resolution of R = 225-430. By repeated observations of the symbiotic emission line star AG Peg, we demonstrate the wavelength stability of the system is <2 Å rms and is limited by the positioning of the object in the slit. The spectrograph is now in routine operation monitoring the activity of comet 67P/Churyumov-Gerasimenko during its current post-perihelion apparition.

  20. Design, construction, and implementation of a ground-based solar spectrograph for the National Student Solar Spectrograph Competition

    NASA Astrophysics Data System (ADS)

    Keeler, E.; Moen, D.; Peck, C.; Zimny, C.; Repasky, K.

    2012-10-01

    A solar spectrograph is an instrument that takes incoming sunlight over a specified portion of the sun's emitted electromagnetic spectrum and separates the light into its constituent frequency components, or spectrum. The components are then sent to a detector that measures intensity, which reveals the location of spectral properties of the light such as absorption and emission lines. The National Student Solar Spectrograph Competition (NSSSC) is a Montana Space Grant Consortium sponsored competition where undergraduate student teams from across the country design, build, and implement a ground-based solar spectrograph to perform any solar related task and demonstrate their spectrographs for the competition in May 2012 in Bozeman, MT. Each team is given a 2,000-dollar budget to build their spectrograph, which cannot be exceeded, and all spectrographs must follow regulations in the NSSSC guidelines. This team designed a spectrograph to be capable of imaging the sun across the visible spectrum using spatial filters and a standard photo detector rather than a traditional charge-coupled device due to budget limitations. The spectrograph analyzes the spectrum of small sections of the sun to determine how the spectrum varies across solar features such as the corona, active regions, and quiet regions. In addition to solar imaging, the spectrograph will also analyze atmospheric absorption of the solar spectrum by comparing the measured spectrum to the theoretical spectrum calculated from the blackbody equation.

  1. Ureilite compaction

    NASA Astrophysics Data System (ADS)

    Walker, D.; Agee, C. B.

    1988-03-01

    Ureilite meteorites show the simple mineralogy and compact recrystallized textures of adcumulate rock or melting residues. A certain amount of controversy exists about whether they are in fact adcumulate rocks or melting residues and about the nature of the precursor liquid or solid assemblage. The authors undertook a limited experimental study which made possible the evaluation of the potential of the thermal migration mechanism (diffusion on a saturation gradient) for forming ureilite-like aggregates from carbonaceous chondrite precursors. They find that the process can produce compact recrystallized aggregates of silicate crystals which do resemble the ureilities and other interstitial-liquid-free adcumulate rocks in texture.

  2. Solar System Science in the FUSE Band with the Cosmic Origins Spectrograph on HST

    NASA Astrophysics Data System (ADS)

    Osterman, S. N.; Penton, S. V.; Oliveira, C. M.; Cheng, A. F.; Green, J. C.

    2014-12-01

    The Cosmic Origins Spectrograph is a high sensitivity, medium resolution FUV/NUV point source spectrograph currently operating onboard the Hubble Space Telescope that is ideally suited for observing dim, compact objects. By taking advantage of the wide range of grating positions possible and the windowless detector we have developed new observing modes that extend COS sensitivity to 90nm at throughputs comparable to the Far Ultraviolet Spectroscopic Explorer. To date multiple compact solar system objects have been observed using COS, including Galilean moons, the Pluto-Charon system. By extending the wavelength coverage to below the MgF2 window cutoff we enable observations of a wide range of atomic and molecular emissions that have not been accessible since the end of the FUSE mission. These include, for example, S II, III and IV and Cl II and III emissions from the Io plasma torus, Ar I, N I, O I and IV, H2, and CO emissions from comets, and H2 emissions from giant planet atmospheres.

  3. Aries x ray objective grating spectrograph

    NASA Technical Reports Server (NTRS)

    Catura, R. C.

    1991-01-01

    This investigation was initiated in June of 1983. An Aries payload involving a single Wolter 1 telescope was developed and flown under a previous contract and the objective of this work was to add two additional mirrors, nested inside of the then existing mirror and add 12 objective reflection gratings to convert the telescope into a spectrograph. A summary of major milestones in the investigation are given. Results of efforts under this contract prior to 1987 are presented in the form of four reprints of published papers attached to this report. Results of the gamma-ray research are also included in the form of an attached reprint. A summary of other work under the contract since 1987 is given.

  4. A high resolution ultraviolet Shuttle glow spectrograph

    NASA Technical Reports Server (NTRS)

    Carruthers, George R.

    1993-01-01

    The High Resolution Shuttle Glow Spectrograph-B (HRSGS-B) is a small payload being developed by the Naval Research Laboratory. It is intended for study of shuttle surface glow in the 180-400 nm near- and middle-ultraviolet wavelength range, with a spectral resolution of 0.2 nm. It will search for, among other possible features, the band systems of excited NO which result from surface-catalyzed combination of N and O. It may also detect O2 Hertzberg bands and N2 Vegard-Kaplan bands resulting from surface recombination. This wavelength range also includes possible N2+ and OH emissions. The HRSGS-B will be housed in a Get Away Special canister, mounted in the shuttle orbiter payload bay, and will observe the glow on the tail of the orbiter.

  5. Fiber feed for the CFHT Gecko spectrograph

    NASA Astrophysics Data System (ADS)

    Baudrand, Jacques; Vitry, Rene

    2000-08-01

    Motivated by a strong concern to keep maintenance work as low as possible the direction of the CFHT had for some times contemplated the possibility to replace the original mirror train f/20 focus feeding their Gecko High Resolution Coude Spectrograph by a more convenient fiber link coupled to the f/8 Cassegrain focus. A decision supporting that idea was ultimately taken two years ago and our group at the OPM was contacted to build such a system according to precise specifications. This telescope facility, baptized CAFÉ for Cassegrain Fiber Environment, has now arrived to near completion and we are able to present here its main characteristics and the technical solutions that were adopted to meet the CFHT requirements and to provide the system with the best performances in terms of robustness and efficiency.

  6. Fiber Scrambling for High Precision Spectrographs

    NASA Astrophysics Data System (ADS)

    Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.

    2011-05-01

    The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the largest factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam position, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s precision. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personality” of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.

  7. Production-line assembly of 150+ VIRUS spectrographs

    NASA Astrophysics Data System (ADS)

    Marshall, J. L.; Vattiat, Brian; DePoy, D. L.; Hill, Gary J.; Collins, Amanda D.; Lee, Hanshin; Allen, Richard D.; Kelz, Andreas; Bauer, Svend M.; Popow, Emil

    2010-07-01

    The Visual Integral-Field Replicable Unit Spectrograph (VIRUS) instrument is being built to support observations for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) project. The instrument consists of 150+ identical fiber-fed integral field optical spectrographs. This instrument provides a unique challenge in astronomical instrumentation: each of the 150+ instruments must be identical and each component must be interchangeable amongst every other spectrograph in order to ease assembly and maintenance of the instrument. In this paper we describe plans for the production-line assembly of the spectrographs. In particular, we discuss the assembly procedures and design choices that will ensure uniformity of the spectrographs and support the project schedule.

  8. Modelling high resolution Echelle spectrographs for calibrations: Hanle Echelle spectrograph, a case study

    NASA Astrophysics Data System (ADS)

    Chanumolu, Anantha; Jones, Damien; Thirupathi, Sivarani

    2015-06-01

    We present a modelling scheme that predicts the centroids of spectral line features for a high resolution Echelle spectrograph to a high accuracy. Towards this, a computing scheme is used, whereby any astronomical spectrograph can be modelled and controlled without recourse to a ray tracing program. The computations are based on paraxial ray trace and exact corrections added for certain surface types and Buchdahl aberration coefficients for complex modules. The resultant chain of paraxial ray traces and corrections for all relevant components is used to calculate the location of any spectral line on the detector under all normal operating conditions with a high degree of certainty. This will allow a semi-autonomous control using simple in-house, programming modules. The scheme is simple enough to be implemented even in a spreadsheet or in any scripting language. Such a model along with an optimization routine can represent the real time behaviour of the instrument. We present here a case study for Hanle Echelle Spectrograph. We show that our results match well with a popular commercial ray tracing software. The model is further optimized using Thorium Argon calibration lamp exposures taken during the preliminary alignment of the instrument. The model predictions matched the calibration frames at a level of 0.08 pixel. Monte Carlo simulations were performed to show the photon noise effect on the model predictions.

  9. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  10. Applications of Integrated Photonic Spectrographs in astronomy

    NASA Astrophysics Data System (ADS)

    Harris, R. J.; Allington-Smith, J. R.

    2013-02-01

    One of the problems of producing instruments for extremely large telescopes (ELTs) is that their size (and hence cost) scales rapidly with telescope aperture. To try to break this relation alternative new technologies have been proposed, such as the use of the Integrated Photonic Spectrograph (IPS). Due to their diffraction-limited nature, the IPS is claimed to defeat the harsh scaling law applying to conventional instruments. In contrast to photonic applications, devices for astronomy are not usually used at the diffraction limit. Therefore, to retain throughput and spatial information, the IPS requires a photonic lantern (PL) to decompose the input multi-mode light into single modes. This is then fed into either numerous arrayed waveguide gratings (AWGs) or a conventional spectrograph. We investigate the potential advantage of using an IPS instead of conventional monolithic optics for a variety of capabilities represented by existing instruments on 8 m telescopes and others planned for ELTs. To do this, we have constructed toy models of different versions of the IPS and calculated the relative instrument sizes and the number of detector pixels required. This allows us to quantify the relative size/cost advantage for instruments aimed at different science requirements. We show that a full IPS instrument is equivalent to an image slicer. Image slicing is a beneficial strategy for ELTs as previously demonstrated. However, the requirement to decompose the input light into individual modes imposes a redundancy in terms of the numbers of components and detector pixels in many cases which acts to cancel out the advantage of the small size of the photonic components. However, there are specific applications where an IPS gives a potential advantage which we describe. Furthermore, the IPS approach has the potential advantage of minimizing or eliminating bulk optics. We show that AWGs fed with multiple single-mode inputs from an PL require relatively bulky auxiliary optics

  11. The Interface Region Imaging Spectrograph (IRIS)

    NASA Astrophysics Data System (ADS)

    De Pontieu, B.; Title, A. M.; Lemen, J. R.; Kushner, G. D.; Akin, D. J.; Allard, B.; Berger, T.; Boerner, P.; Cheung, M.; Chou, C.; Drake, J. F.; Duncan, D. W.; Freeland, S.; Heyman, G. F.; Hoffman, C.; Hurlburt, N. E.; Lindgren, R. W.; Mathur, D.; Rehse, R.; Sabolish, D.; Seguin, R.; Schrijver, C. J.; Tarbell, T. D.; Wülser, J.-P.; Wolfson, C. J.; Yanari, C.; Mudge, J.; Nguyen-Phuc, N.; Timmons, R.; van Bezooijen, R.; Weingrod, I.; Brookner, R.; Butcher, G.; Dougherty, B.; Eder, J.; Knagenhjelm, V.; Larsen, S.; Mansir, D.; Phan, L.; Boyle, P.; Cheimets, P. N.; DeLuca, E. E.; Golub, L.; Gates, R.; Hertz, E.; McKillop, S.; Park, S.; Perry, T.; Podgorski, W. A.; Reeves, K.; Saar, S.; Testa, P.; Tian, H.; Weber, M.; Dunn, C.; Eccles, S.; Jaeggli, S. A.; Kankelborg, C. C.; Mashburn, K.; Pust, N.; Springer, L.; Carvalho, R.; Kleint, L.; Marmie, J.; Mazmanian, E.; Pereira, T. M. D.; Sawyer, S.; Strong, J.; Worden, S. P.; Carlsson, M.; Hansteen, V. H.; Leenaarts, J.; Wiesmann, M.; Aloise, J.; Chu, K.-C.; Bush, R. I.; Scherrer, P. H.; Brekke, P.; Martinez-Sykora, J.; Lites, B. W.; McIntosh, S. W.; Uitenbroek, H.; Okamoto, T. J.; Gummin, M. A.; Auker, G.; Jerram, P.; Pool, P.; Waltham, N.

    2014-07-01

    The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, and corona with 0.33 - 0.4 arcsec spatial resolution, two-second temporal resolution, and 1 km s-1 velocity resolution over a field-of-view of up to 175 arcsec × 175 arcsec. IRIS was launched into a Sun-synchronous orbit on 27 June 2013 using a Pegasus-XL rocket and consists of a 19-cm UV telescope that feeds a slit-based dual-bandpass imaging spectrograph. IRIS obtains spectra in passbands from 1332 - 1358 Å, 1389 - 1407 Å, and 2783 - 2834 Å, including bright spectral lines formed in the chromosphere (Mg ii h 2803 Å and Mg ii k 2796 Å) and transition region (C ii 1334/1335 Å and Si iv 1394/1403 Å). Slit-jaw images in four different passbands (C ii 1330, Si iv 1400, Mg ii k 2796, and Mg ii wing 2830 Å) can be taken simultaneously with spectral rasters that sample regions up to 130 arcsec × 175 arcsec at a variety of spatial samplings (from 0.33 arcsec and up). IRIS is sensitive to emission from plasma at temperatures between 5000 K and 10 MK and will advance our understanding of the flow of mass and energy through an interface region, formed by the chromosphere and transition region, between the photosphere and corona. This highly structured and dynamic region not only acts as the conduit of all mass and energy feeding into the corona and solar wind, it also requires an order of magnitude more energy to heat than the corona and solar wind combined. The IRIS investigation includes a strong numerical modeling component based on advanced radiative-MHD codes to facilitate interpretation of observations of this complex region. Approximately eight Gbytes of data (after compression) are acquired by IRIS each day and made available for unrestricted use within a few days of the observation.

  12. Interstellar Medium Absorption Profile Spectrograph (IMAPS)

    NASA Technical Reports Server (NTRS)

    Jenkins, E. B.

    1985-01-01

    The design and fabrication of an objective-grating echelle spectrograph to fly on sounding rockets and record spectra of stars from approximately 920 to 1120A with a resolving power lambda/delta lambda = 200,000 is discussed. The scientific purpose of the program is to observe, with ten times better velocity resolution than before, the plentiful absorption lines in this spectral region produced by atoms, ions and molecules in the interstellar medium. In addition, an important technical goal is to develop and flight-quality a new ultraviolet, photon-counting image sensor which has a windowless, opaque photocathode and a CCD bombarded directly by the accelerated photoelectrons. Except for some initial difficulties with the performance of CCDs, the development of the payload instrument is relatively straightforward and our overall design goals are satisfied. The first flight occurred in late 1984, but no data were obtained because of an inrush of air degraded the instrument's vacuum and caused the detector's high voltage to arc. A second flight in early 1985 was a complete success and obtained a spectrum of pi Sco. Data from this mission are currently being reduced; quick-look versions of the spectra indicate that excellent results will be obtained. Currently, the payload is being reconfigured to fly on a Spartan mission in 1988.

  13. Interstellar Medium Absorption Profile Spectrograph (IMAPS)

    NASA Astrophysics Data System (ADS)

    Jenkins, E. B.

    1985-08-01

    The design and fabrication of an objective-grating echelle spectrograph to fly on sounding rockets and record spectra of stars from approximately 920 to 1120A with a resolving power lambda/delta lambda = 200,000 is discussed. The scientific purpose of the program is to observe, with ten times better velocity resolution than before, the plentiful absorption lines in this spectral region produced by atoms, ions and molecules in the interstellar medium. In addition, an important technical goal is to develop and flight-quality a new ultraviolet, photon-counting image sensor which has a windowless, opaque photocathode and a CCD bombarded directly by the accelerated photoelectrons. Except for some initial difficulties with the performance of CCDs, the development of the payload instrument is relatively straightforward and our overall design goals are satisfied. The first flight occurred in late 1984, but no data were obtained because of an inrush of air degraded the instrument's vacuum and caused the detector's high voltage to arc. A second flight in early 1985 was a complete success and obtained a spectrum of pi Sco. Data from this mission are currently being reduced; quick-look versions of the spectra indicate that excellent results will be obtained. Currently, the payload is being reconfigured to fly on a Spartan mission in 1988.

  14. Galactic Archeology - Requirements on Survey Spectrographs

    NASA Astrophysics Data System (ADS)

    Feltzing, S.

    2016-10-01

    Galactic Archeology is about exploring the Milky Way as a galaxy by, mainly, using its (old) stars as tracers of past events and thus to figure out the formation and evolution of our Galaxy. I will briefly outline some of the key scientific aspects of Galactic Archeology and then discuss the associated instrumentation. Gaia will forever change the way we approach this subject. However, Gaia on its own is not enough. Ground-based complementary spectroscopy is necessary to obtain full phase-space information and elemental abundances for stars fainter than the top few percent of the bright part of the Gaia catalog. I will review the requirement on instrumentation for Gaia follow-up that Galactic Archeology sets. In particular, I will discuss the requirements on radial velocity and elemental abundance determination, including a brief look at potential pitfalls in the abundance analysis (e.g., NLTE, atomic diffusion). This contribution also provides a non-exhaustive comparison of the various current and future spectrographs for Galactic Archeology. Finally, I will discuss the needs for astrophysical calibrations for the surveys and inter-survey calibrations.

  15. Compact magnetograph

    NASA Technical Reports Server (NTRS)

    Title, A. M.; Gillespie, B. A.; Mosher, J. W.

    1982-01-01

    A compact magnetograph system based on solid Fabry-Perot interferometers as the spectral isolation elements was studied. The theory of operation of several Fabry-Perot systems, the suitability of various magnetic lines, signal levels expected for different modes of operation, and the optimal detector systems were investigated. The requirements that the lack of a polarization modulator placed upon the electronic signal chain was emphasized. The PLZT modulator was chosen as a satisfactory component with both high reliability and elatively low voltage requirements. Thermal control, line centering and velocity offset problems were solved by a Fabry-Perot configuration.

  16. Wavefront Sensing Using a Multi-Object Spectrograph (NIRSpec)

    NASA Technical Reports Server (NTRS)

    Dean, Bruce H.; Boucarut, Rene; Hadjimichael, Theo; Smith, Scott

    2004-01-01

    An analysis is presented that illustrates how the James Webb Space Telescope (JWST) fine-phasing process can be carried out using the Near-Infrared Spectrograph (NIRSpec) data collected at the science focal plane. The analysis considers a multi-plane diffraction model which properly accounts for the microshutter diffractive element placed at the first relay position of the spectrograph. Wavefront sensing results are presented based on data collected from the NASA Goddard Microshutter Testbed.

  17. X-ray spectrographic determination of cesium and rubidium

    USGS Publications Warehouse

    Axelrod, J.M.; Adler, I.

    1957-01-01

    An x-ray spectrographic method for the determination of rubidium and cesium was developed, using the internal-standard method and a four-channel flat-crystal spectrograph. The sensitivity is within 0.1% for cesia and 0.02% for rubidia; the precision is within 10% of the amount present. Results agree well with those obtained by flame photometry and by radio-activation.

  18. The Kyoto Tridimensional Spectrograph II on Subaru and the University of Hawaii 88 in Telescopes

    NASA Astrophysics Data System (ADS)

    Sugai, H.; Hattori, T.; Kawai, A.; Ozaki, S.; Hayashi, T.; Ishigaki, T.; Ishii, M.; Ohtani, H.; Shimono, A.; Okita, Y.; Matsubayashi, K.; Kosugi, G.; Sasaki, M.; Takeyama, N.

    2010-01-01

    In order to investigate physical conditions of ionized gas in galaxies, as well as its kinematics, we have developed the Kyoto tridimensional spectrograph II. It is a multimode optical instrument, including integral field spectrograph (IFS) and Fabry-Perot imager modes. We have designed it compact so that we can mount it on 2 m class telescopes as well as on the 8.2 m Subaru telescope. Special care was taken to obtain high-quality calibrations in the IFS mode. In order to remove the chromatic aberration of micropupil images produced by a lenslet array, we have introduced a corrector lens system behind the lenslet array. The internal calibration system simulates the telescope optics so that the system provides micropupil images identical to those produced by the telescope. The rigidness of the instrument provides the positional stability of micropupil images. We have succeeded in test observations of all the modes on Subaru and the University of Hawaii 88 in (UH88) telescopes and have verified the performance of the instrument. This includes the instrument efficiencies as well as the effective sky background subtraction and the minimization of crosstalk effects in the IFS mode. In the IFS mode a spatial resolution of 0.4'' was obtained in good seeing conditions. Each of 37 × 37 lenslets subtends 0.1'' in Subaru's case. This samples the image size well. A wider field of view is emphasized in the case of UH88.

  19. Chemical Abundances of Compact Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Lee, Ting-Hui; Shaw, Richard A.; Stanghellini, letizia; Riley, Ben

    2015-08-01

    We present preliminary results from an optical spectroscopic survey of compact planetary nebulae (PNe) in the Galactic disk. This is an ongoing optical+infrared spectral survey of 150 compact PNe to build a deep sample of PN chemical abundances. We obtained optical spectra of PNe with the Southern Astrophysical Research (SOAR) Telescope and Goodman High-Throughput Spectrograph between 2012 and 2015. These data were used to calculate the nebulae diagnostics such as electron temperature and density for each PN, and to derive the elemental abundances of He, N, O Ne, S and Ar. These abundances are vital to understanding the nature of the PNe, and their low- to intermediate-mass progenitor stars.

  20. The Mitchell Spectrograph: Studying Nearby Galaxies with the VIRUS Prototype

    NASA Astrophysics Data System (ADS)

    Blanc, Guillermo A.

    The Mitchell Spectrograph (a.k.a. VIRUS-P) on the 2.7m Harlan J. Smith telescope at McDonald Observatory is currently the largest field of view (FOV) integral field unit (IFU) spectrograph in the world (1.7'x1.7'). It was designed as a prototype for the highly replicable VIRUS spectrograph which consists of a mosaic of IFUs spread over a 16' diameter FOV feeding 150 spectrographs similar to the Mitchell. VIRUS will be deployed on the 9.2 meter Hobby-Eberly Telescope (HET) and will be used to conduct the HET Dark Energy Experiment (HETDEX). Since seeing first light in 2007 the Mitchell Spectrograph has been widely used, among other things, to study nearby galaxies in the local universe where their internal structure and the spatial distribution of different physical parameters can be studied in great detail. These observations have provided important insight into many aspects of the physics behind the formation and evolution of galaxies and have boosted the scientific impact of the 2.7 meter telescope enormously. Here I review the contributions of the Mitchell Spectrograph to the study of nearby galaxies, from the investigation of the spatial distribution of dark matter and the properties of supermassive black holes, to the studies of the process of star formation and the chemical composition of stars and gas in the ISM, which provide important information regarding the formation and evolution of these systems. I highlight the fact that wide field integral field spectrographs on small and medium size telescopes can be powerful cost effective tools to study the astrophysics of galaxies. Finally I briefly discuss the potential of HETDEX for conducting studies on nearby galaxies. The survey parameters make it complimentary and competitive to ongoing and future surveys like SAMI and MANGA.

  1. Construction of pre-slit system of Chinese SONG spectrograph

    NASA Astrophysics Data System (ADS)

    Gao, Pengfei; Hu, Zhongwen; Dai, Songxin

    2015-10-01

    The pre-slit system of Chinese SONG spectrograph is a multi-function unit. The main function is to direct the incoming light from the coudé path to the entrance slit of the spectrograph. The specific functions includes maintaining exit pupil stable, fast guiding and telescope focus corrections. The original optics of this pre-slit system were designed by Aarhus University in Denmark. We built the system and designed the software for it. This system holds a guide/slit-viewing camera, a pupil-viewing camera, two tip-tilt mirrors and its tip-tilt controllers. So it includes two sets of the fast-steering mirror systems applied to image tracking and correction. When this image tracking and correction systems is running, the real-time software algorithm will be presented and simulated simultaneously. From the images taken with camera, a closed loop signals are generated for the tip-tilt mirror to correct image motion. When the camera exposure time is 25ms,the correcting frequency of slit imge tip-tilt motion is about 30Hz. The correcting frequency of pupil imge tip-tilt motion is about 1Hz. In addition, a temperature control system surrounding the spectrograph is necessary to keep spectrograph at a constant temperature. The test results shows that the error is about +/-0.005°C in 69.4 hours. The results prove that the pre-slit system of Chinese SONG spectrograph is effective and feasible.

  2. An introduction to the World Space Observatory-Ultraviolet spectrographs

    NASA Astrophysics Data System (ADS)

    Hermanutz, S.; Barnstedt, J.; Diebold, S.; Elsener, H. R.; Ganz, P. R.; Kalkuhl, C.; Kappelmann, N.; Pfeifer, M.; Tanirah, O.; Sachkov, M.; Schaadt, D. M.; Schanz, T.; Shustov, B. M.; Werner, K.

    2012-09-01

    The World Space Observatory Ultraviolet (WSO-UV) is a multinational mission under the leadership of Russia with contributions of Spain and Germany. The mission is part of the Spektrum series and launch is currently scheduled for 2016. It consists of a 1.7m mirror focusing on spectrographs in the range of 102-310 nm withh a resolution of R >= 55,000 for high resolution spectral observations, a long-slit-spectrograph for spatially resolved observations and an imager. According to the Phase-B-Study all spectrographs will use the same detectors built by the IAAT. These spectrographs are designed to observe cosmic plasma with temperatures of several ten thousands Kelvin and atomic transition lines of all important atoms and molecuules like H2, CO, OH eetc. In knowledge about the formation of galaxies and analyze the atmospheres of extrasolar planets and protoplanetary discs. To achieve these goals the IAAT designed in cooperation with the Leibniz-Institute for Analytical Sciences (ISAS Berlin) the spectrographs. In addition Tubingen develops and builds a new type of michrchannel plate detector based on gallim nitride cathods and a cross-strip-anode.

  3. The optical design of wide integral field infrared spectrograph

    NASA Astrophysics Data System (ADS)

    Chou, Richard C. Y.; Moon, Dae-Sik; Eikenberry, Stephen S.

    2010-07-01

    We present the optical design of the Wide Integral Field Infrared Spectrograph (WIFIS) which provides an unprecedented combination of the integral field size and the spectral resolving power in the near-infrared wavebands. The integral field size and spectral resolving power of WIFIS are ~ 5× 12on a 10-m telescope (or equivalently 13× 30on a 4-m telescope) and ~ 5300, respectively. Therefore, the affordable etendue of WIFIS is larger than any other near-infrared integral field spectrographs while its spectral resolving power is comparable to the highest value provided by other spectrographs. WIFIS optical system comprises an Offner relay-based pre-slit unit, an image slicer for integral-field unit, a collimator, diffraction gratings, and a spectrograph camera. For the integral field unit, WIFIS uses the Florida Image Slicer for Infrared Cosmological and Astrophysics which is a set of 3 monolithic mirror arrays housing 22 image slicers. The collimator system consists of one off-axis parabola and two lenses, while WIFIS relies on 3 different gratings to cover the entire JHK bands. The spectrograph camera uses 6 lenses of CaF2 and SFTM16, delivering the f/3 final beam onto a Hawaii II RG 2K × 2K detector array. WIFIS will be an ideal instrument to study the dynamics and chemistry of extended objects.

  4. Compact Reactor

    SciTech Connect

    Williams, Pharis E.

    2007-01-30

    Weyl's Gauge Principle of 1929 has been used to establish Weyl's Quantum Principle (WQP) that requires that the Weyl scale factor should be unity. It has been shown that the WQP requires the following: quantum mechanics must be used to determine system states; the electrostatic potential must be non-singular and quantified; interactions between particles with different electric charges (i.e. electron and proton) do not obey Newton's Third Law at sub-nuclear separations, and nuclear particles may be much different than expected using the standard model. The above WQP requirements lead to a potential fusion reactor wherein deuterium nuclei are preferentially fused into helium nuclei. Because the deuterium nuclei are preferentially fused into helium nuclei at temperatures and energies lower than specified by the standard model there is no harmful radiation as a byproduct of this fusion process. Therefore, a reactor using this reaction does not need any shielding to contain such radiation. The energy released from each reaction and the absence of shielding makes the deuterium-plus-deuterium-to-helium (DDH) reactor very compact when compared to other reactors, both fission and fusion types. Moreover, the potential energy output per reactor weight and the absence of harmful radiation makes the DDH reactor an ideal candidate for space power. The logic is summarized by which the WQP requires the above conditions that make the prediction of DDH possible. The details of the DDH reaction will be presented along with the specifics of why the DDH reactor may be made to cause two deuterium nuclei to preferentially fuse to a helium nucleus. The presentation will also indicate the calculations needed to predict the reactor temperature as a function of fuel loading, reactor size, and desired output and will include the progress achieved to date.

  5. Ceramic powder compaction

    SciTech Connect

    Glass, S.J.; Ewsuk, K.G.; Mahoney, F.M.

    1995-12-31

    With the objective of developing a predictive model for ceramic powder compaction we have investigated methods for characterizing density gradients in ceramic powder compacts, reviewed and compared existing compaction models, conducted compaction experiments on a spray dried alumina powder, and conducted mechanical tests and compaction experiments on model granular materials. Die filling and particle packing, and the behavior of individual granules play an important role in determining compaction behavior and should be incorporated into realistic compaction models. These results support the use of discrete element modeling techniques and statistical mechanics principals to develop a comprehensive model for compaction, something that should be achievable with computers with parallel processing capabilities.

  6. The construction, alignment, and installation of the VIRUS spectrograph

    NASA Astrophysics Data System (ADS)

    Tuttle, Sarah E.; Hill, Gary J.; Lee, Hanshin; Vattiat, Brian; Noyola, Eva; Drory, Niv; Cornell, Mark; Peterson, Trent; Chonis, Taylor; Allen, Richard; Dalton, Gavin; DePoy, Darren; Edmonston, Doug; Fabricius, Maximillian; Haynes, Dionne; Kelz, Andreas; Landriau, Martin; Lesser, Michael; Leach, Bob; Marshall, Jennifer; Murphy, Jeremy; Perry, David; Prochaska, Travis; Ramsey, Jason; Savage, Richard

    2014-07-01

    VIRUS is the massively replicated fiber-fed spectrograph being built for the Hobby-Eberly Telescope to support HETDEX (the Hobby-Eberly Telescope Dark Energy Experiment). The instrument consists of 156 identical channels, fed by 34,944 fibers contained in 78 integral field units, deployed in the 22 arcminute field of the upgraded HET. VIRUS covers 350-550nm at R ≍ 700 and is built to target Lyman α emitters at 1.9 < z < 3.5 to measure the evolution of dark energy. Here we present the assembly line construction of the VIRUS spectrographs, including their alignment and plans for characterization. We briefly discuss plans for installation on the telescope. The spectrographs are being installed on the HET in several stages, and the instrument is due for completion by the end of 2014.

  7. Sky background subtraction with fiber-fed spectrographs

    NASA Astrophysics Data System (ADS)

    Puech, M.; Rodrigues, M.; Yang, Y.; Flores, H.; Royer, F.; Disseau, K.; Gonçalves, T.; Hammer, F.; Cirasuolo, M.; Evans, C. J.; Li Causi, G.; Maiolino, R.; Melo, C.

    2014-08-01

    Fiber-fed spectrographs can now have throughputs equivalent to slit spectrographs. However, the sky subtraction accuracy that can be reached on such instruments has often been pinpointed as one of their major issues, in relation to difficulties in scattered light and flat-field corrections or throughput losses associated with fibers. Using technical time observations with FLAMES-GIRAFFE, two observing techniques, namely dual staring and cross beam switching modes, were tested and the resulting sky subtraction accuracy reached in both cases was quantified. Results indicate that an accuracy of 0.6% on the sky subtraction can be reached, provided that the cross beam switching mode is used. This is very encouraging regarding the detection of very faint sources with future fiber-fed spectrographs such as VLT/MOONS or E-ELT/MOSAIC.

  8. Optical design of the SuMIRe/PFS spectrograph

    NASA Astrophysics Data System (ADS)

    Pascal, Sandrine; Vives, Sébastien; Barkhouser, Robert; Gunn, James E.

    2014-07-01

    The SuMIRe Prime Focus Spectrograph (PFS), developed for the 8-m class SUBARU telescope, will consist of four identical spectrographs, each receiving 600 fibers from a 2394 fiber robotic positioner at the telescope prime focus. Each spectrograph includes three spectral channels to cover the wavelength range [0.38-1.26] um with a resolving power ranging between 2000 and 4000. A medium resolution mode is also implemented to reach a resolving power of 5000 at 0.8 um. Each spectrograph is made of 4 optical units: the entrance unit which produces three corrected collimated beams and three camera units (one per spectral channel: "blue, "red", and "NIR"). The beam is split by using two large dichroics; and in each arm, the light is dispersed by large VPH gratings (about 280x280mm). The proposed optical design was optimized to achieve the requested image quality while simplifying the manufacturing of the whole optical system. The camera design consists in an innovative Schmidt camera observing a large field-of-view (10 degrees) with a very fast beam (F/1.09). To achieve such a performance, the classical spherical mirror is replaced by a catadioptric mirror (i.e meniscus lens with a reflective surface on the rear side of the glass, like a Mangin mirror). This article focuses on the optical architecture of the PFS spectrograph and the perfornance achieved. We will first described the global optical design of the spectrograph. Then, we will focus on the Mangin-Schmidt camera design. The analysis of the optical performance and the results obtained are presented in the last section.

  9. Correction of stray light in spectrographs: implications for remote sensing

    NASA Astrophysics Data System (ADS)

    Zong, Yuqin; Brown, Steven W.; Johnson, B. C.; Lykke, Keith R.; Ohno, Yoshi

    2005-08-01

    Spectrographs are used in a variety of applications in the field of remote sensing for radiometric measurements due to the benefits of measurement speed, sensitivity, and portability. However, spectrographs are single grating instruments that are susceptible to systematic errors arising from stray radiation within the instrument. In the application of measurements of ocean color, stray light of the spectrographs has led to significant measurement errors. In this work, a simple method to correct stray-light errors in a spectrograph is described. By measuring a set of monochromatic laser sources that cover the instrument's spectral range, the instrument's stray-light property is characterized and a stray-light correction matrix is derived. The matrix is then used to correct the stray-light error in measured raw signals by a simple matrix multiplication, which is fast enough to be implemented in the spectrograph's firmware or software to perform real-time corrections: an important feature for remote sensing applications. The results of corrections on real instruments demonstrated that the stray-light errors were reduced by one to two orders of magnitude, to a level of approximately 10-5 for a broadband source measurement, which is a level less than one count of a 15-bit resolution instrument. As a stray-light correction example, the errors in measurement of solar spectral irradiance using a highquality spectrograph optimized for UV measurements are analyzed; the stray-light correction leads to reduction of errors from a 10 % level to a 1 % level in the UV region. This method is expected to contribute to achieving a 0.1 % level of uncertainty required for future remote-sensing applications.

  10. National Student Solar Spectrograph Competition Overview and Results

    NASA Astrophysics Data System (ADS)

    Des Jardins, Angela C.; Larimer, R.; Shaw, J. A.; Kankelborg, C.; Palmer, C.; Key, J. S.; Nakagawa, W.; Springer, L.; Knighton, W.; Repasky, K. S.; Pust, N. J.; Babbitt, W.; Jaeggli, S. A.; Hobish, M. K.; Wilson, E. W.; Anderson, M.; Boger, J.; McCrady, N.; Naylor, J.; Turcotte, S.; Lines, T.; Strobel, N.; Cooper, W.; Darke, R.; Head, R.; Kimball, D.; Kissel, G.; Buck, K.; Lawrence, L.; Wragg, J.; Runyon, C. J.; Spacher, P.; Dumitriu, I.; Nollenberg, J. G.; Estaban, R.

    2013-07-01

    The yearly National Student Solar Spectrograph Competition (NSSSC) is Montana Space Grant Consortium's Education and Public Outreach (EP/O) Program for NASA's Interface Region Imaging Spectrograph (IRIS) mission. The NSSSC is designed to give institutions with less aerospace activity such as Minority Serving Institutions and Community Colleges an opportunity for hands on real world research experience. The NSSSC provides students from across the country the opportunity to work as part of an undergraduate interdisciplinary team to design, build and test a ground based solar spectrograph. Over the course of nine months, teams come up with their own science goals and then build an instrument to collect data in support of their goals. Teams then travel to Bozeman, MT to demonstrate their instruments and present their results in a competitive science fair environment. This poster will present the 2012-2013 competition results.Abstract (2,250 Maximum Characters): The yearly National Student Solar Spectrograph Competition (NSSSC) is Montana Space Grant Consortium's Education and Public Outreach (EP/O) Program for NASA's Interface Region Imaging Spectrograph (IRIS) mission. The NSSSC is designed to give institutions with less aerospace activity such as Minority Serving Institutions and Community Colleges an opportunity for hands on real world research experience. The NSSSC provides students from across the country the opportunity to work as part of an undergraduate interdisciplinary team to design, build and test a ground based solar spectrograph. Over the course of nine months, teams come up with their own science goals and then build an instrument to collect data in support of their goals. Teams then travel to Bozeman, MT to demonstrate their instruments and present their results in a competitive science fair environment. This poster will present the 2012-2013 competition results.

  11. The AVES adaptive optics spectrograph for the VLT: status report

    NASA Astrophysics Data System (ADS)

    Pallavicini, Roberto; Delabre, Bernard; Pasquini, Luca; Zerbi, Filippo M.; Bonanno, Giovanni; Comari, Maurizio; Conconi, Paolo; Mazzoleni, Ruben; Santin, Paolo; Damiani, Francesco; Di Marcantonio, Paolo; Franchini, Mariagrazia; Spano, Paolo; Bonifacio, P.; Catalano, Santo; Molaro, Paolo P.; Randich, S.; Rodono, Marcello

    2003-03-01

    We report on the status of AVES, the Adaptive-optics Visual Echelle Spectrograph proposed for the secondary port of the Nasmyth Adaptive Optics System (NAOS) recently installed at the VLT. AVES is an intermediate resolution (R ≍ 16,000) high-efficiency fixed- format echelle spectrograph which operates in the spectral band 500 - 1,000 nm. In addition to a high intrinsic efficiency, comparable to that of ESI at Keck II, it takes advantage of the adaptive optics correction provided by NAOS to reduce the sky and detector contribution in background-limited observations of weak sources, thus allowing a further magnitude gain with respect to comparable non-adaptive optics spectrographs. Simulations show that the instrument will be capable of reaching a magnitude V = 22.5 at S/N > 10 in two hours, two magnitudes weaker than GIRAFFE at the same resolution and 3 magnitudes weaker than the higher resolution UVES spectrograph. Imaging and coronographic functions have also been implemented in the design. We present the results of the final design study and we dicuss the technical and operational issues related to its implementation at the VLT as a visitor instrument. We also discuss the possibility of using a scaled-up non-adaptive optics version of the same design as an element of a double- or triple-arm intermediate-resolution spectrograph for the VLT. Such an option looks attractive in the context of a high-efficiency large-bandwidth (320 - 1,500 nm) spectrograph ("fast-shooter") being considered by ESO as a 2nd-generation VLT instrument.

  12. Extreme Precision Environmental Control for Next Generation Radial Velocity Spectrographs

    NASA Astrophysics Data System (ADS)

    Stefansson, Gudmundur K.; Hearty, Fred; Levi, Eric; Robertson, Paul; Mahadevan, Suvrath; Bender, Chad; Nelson, Matt; Halverson, Samuel

    2015-12-01

    Extreme radial velocity precisions of order 10cm/s will enable the discoveries of Earth-like planets around solar-type stars. Temperature and pressure variations inside a spectrograph can lead to thermomechanical instabilities in the optics and mounts, and refractive index variations in both the optical elements as well as the surrounding air. Together, these variations can easily induce instrumental drifts of several tens to hundreds of meters per second. Enclosing the full optical train in thermally stabilized high-vacuum environments minimizes such errors. In this talk, I will discuss the Environmental Control System (ECS) for the Habitable Zone Planet Finder (HPF) spectrograph: a near infrared (NIR) facility class instrument we will commission at the Hobby Eberly Telescope in 2016. The ECS will maintain the HPF optical bench stable at 180K at the sub milli-Kelvin level on the timescale of days, and at the few milli-Kelvin level over months to years. The entire spectrograph is kept under high-quality vacuum (<10-6 Torr), and environmental temperature fluctuations are compensated for with an actively controlled radiation shield outfitted with custom feedback electronics. High efficiency Multi-Layer Insulation (MLI) blankets, and a passive external thermal enclosure further isolate the optics from ambient perturbations. This environmental control scheme is versatile, suitable to stabilize both next generation NIR, and optical spectrographs. I will show how we are currently testing this control system for use with our design concept of the Extreme Precision Doppler Spectrograph (EPDS), the next generation optical spectrograph for the WIYN 3.5m telescope. Our most recent results from full-scale stability tests will be presented.

  13. Successful "First Light" for VLT High-Resolution Spectrograph

    NASA Astrophysics Data System (ADS)

    1999-10-01

    quite faint objects, down to about magnitude 20 (corresponding to nearly one million times fainter than what can be perceived with the unaided eye). The possibility of doing simultaneous observations in the two channels (with a dichroic mirror) ensures a further gain in data gathering efficiency. First Observations with UVES In the evening of September 27, 1999, the ESO astronomers turned the KUEYEN telescope and - for the first time - focussed the light of stars and galaxies on the entrance aperture of the UVES instrument. This is the crucial moment of "First Light" for a new astronomical facility. The following test period will last about three weeks. Much of the time during the first observing nights was spent by functional tests of the various observation modes and by targeting "standard stars" with well-known properties in order to measure the performance of the new instrument. They showed that it is behaving very well. This marks the beginning of a period of progressive fine-tuning that will ultimately bring UVES to peak performance. The astronomers also did a few "scientific" observations during these nights, aimed at exploring the capabilities of their new spectrograph. They were eager to do so, also because UVES is the first spectrograph of this type installed at a telescope of large diameter in the southern hemisphere . Many exciting research possibilities are now opening with UVES . They include a study of the chemical history of many galaxies in the Local Group, e.g. by observing the most metal-poor (oldest) stars in the Milky Way Galaxy and by obtaining the first, extremely detailed spectra of their brightest stars in the Magellanic Clouds. Quasars and distant compact galaxies will also be among the most favoured targets of the first UVES observers, not least because their spectra carry crucial information about the density, physical state and chemical composition of the early Universe. UVES First Light: SN 1987A One of the first spectral test exposures

  14. GRASSP: a spectrograph for the study of transient luminous events.

    PubMed

    Passas, María; Sánchez, Justo; Sánchez-Blanco, Ernesto; Luque, Alejandro; Gordillo-Vázquez, Francisco J

    2016-08-10

    We present the main parameters, design features, and optical characterization of the Granada Sprite Spectrograph and Polarimeter (GRASSP), a ground-based spectrographic system intended for the analysis of the spectroscopic signature of transient luminous events (TLEs) occurring in the mesosphere of the Earth. It has been designed to measure the spectra of the light emitted from TLEs with a mean spectral resolution of 0.235 nm and 0.07 nm/px dispersion in the wavelength range between 700 and 800 nm. PMID:27534491

  15. The current status of the UK-FMOS spectrograph

    NASA Astrophysics Data System (ADS)

    Tosh, Ian A.; Woodhouse, Guy F.; Froud, Tim; Dowell, Allan; Patel, Mukesh; Wallner, Mattias; Lewis, Ian J.; Dalton, Gavin B.; Holmes, Alan; Brooks, Barney; Band, Cyril; Bonfield, David G.; Murray, Graham J.; Robertson, David J.; Dipper, Nigel A.

    2004-09-01

    FMOS is a near-IR OH-suppressed multi-fibre fed spectrograph for the Subaru telescope. The spectrograph will accept 200 optical fibres from the ECHIDNA positioner system at the 30arcmin Prime focus of the telescope. We will describe the recent activities here in the UK in progressing the instrument from its conceptual phase through detailed design and into manufacture. A variety of technical areas will be described including: the opto-mechanical system design and construction, development of the HAWAII-II detector control system, the thermal system design & control and OH suppression techniques.

  16. An integral field spectrograph for SNAP supernova studies

    SciTech Connect

    Ealet, Anne; Prieto, E.; Bonissent, A.; Malina, R.; Basa, S.; LeFevre, O.; Mazure, A.; Tarle, G.; Akerlof, C.W.; Aldering, G.; Amidei, D.E.; Astier, P.; Baden, A.R.; Bebek, C.; Bergstrom, L.; Bernstein, G.M.; Bower, C.R.; Campbell, M.; Carithers Jr., W.C.; Commins, E.D.; Curtis, D.W.; Deustua, S.E.; Edwards, W.R.; Ellis, R.S.; Fruchter, A.; Frye, B.L.; Genat, J.; Goldhaber, G.; Goobar, A.; Goodman, J.A.; Graham, J.R.; Hardin, D.; Harris, S.E.; Harvey, P.R.; Heetderks, H.D.; Honeycutt, R.; Holland, S.E.; Hook, I.; Huterer, D.; Kasen, D.N.; Kim, A.G.; Knop, R.A.; Lafever, R.; Lampton, M.L.; Levi, M.E.; Levin, D.S.; Levy, J.M.; Lidman, C.; Lin, R.P.; Linder, E.V.; Loken, S.C.; McKay, T.; McKee, S.P.; Metzger, M.R.; Miquel, R.; Mourao, A.; Mufson, S.; Musser, J.A.; Nugent, P.E.; Pain, R.; Pankow, D.H.; Pennypacker, C.R.; Perlmutter, S.; Refregier, A.; Rich, J.; Robinson, K.E.; Schahmaneche, K.; Schubnell, M.S.; Spadafora, A.; Smoot, G.F.; Sullivan, G.W.; Tomasch, A.D.; SNAP Collaboration

    2002-07-29

    A well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment. The goal is to ensure proper identification of Type Ia supernovae and to standardize the magnitude of each candidate by determining explosion parameters. An instrument based on an integral field method with the powerful concept of imager slicing has been designed and is presented in this paper. The spectrograph concept is optimized to have very high efficiency and low spectral resolution (R {approx} 100), constant through the wavelength range (0.35-1.7{micro}m), adapted to the scientific goals of the mission.

  17. Fiber optics for astronomical spectroscopy - The Medusa Spectrograph

    NASA Technical Reports Server (NTRS)

    Hill, J. M.; Angel, J. R. P.; Scott, J. S.

    1983-01-01

    An instrument has been built to obtain simultaneous spectra of 32 objects in the field of view of the Steward Observatory 2.3 m telescope. Short lengths of optical fiber are used to bring light from galaxy images at the focus of the telescope into a line at the spectrograph slit. This multi-fiber aperture plate instrument has been dubbed the Medusa Spectrograph. The Medusa is now producing spectra of about 100 galaxies per clear night. An optimized version of the instrument called the MX Spectrometer is being constructed to record spectra at a higher rate. This new instrument will have remotely positioned fibers under computer control. A Charge Coupled Device will be used as the spectrograph detector to allow sky subtraction, give increased dynamic range and provide more accurate wavelength calibration. Transmission characteristics of some commercial fibers are discussed, and the microlens optics used to match the telescope and the spectrograph to the fibers to avoid focal ratio degradation are described.

  18. Versatile nebular insect-eye fabry-perot spectrograph.

    PubMed

    Meaburn, J

    1975-02-01

    The design and performance of an insect-eye F.P. spectrograph used on the 249-cm Isaac Newton telescope, which can also be converted into a nebular filter camera, is presented. This device has several novel features, including a pressure-controlled optically contacted etalon and an image tube as a detector.

  19. Galactic Archaeology with the Subaru Prime Focus Spectrograph

    NASA Astrophysics Data System (ADS)

    Chiba, Masashi; Cohen, Judith; Wyse, Rosemary F. G.

    2016-08-01

    We present an overview of our Galactic Archaeology (GA) survey program with the Prime Focus Spectrograph (PFS) for Subaru. Following successful design reviews, the instrument is now under construction with first light anticipated in 2018. Main characteristics of PFS and the science goals in our PFS/GA program are described.

  20. X-shooter near-IR spectrograph arm realisation

    NASA Astrophysics Data System (ADS)

    Navarro, Ramon; Elswijk, Eddy; Tromp, Niels; ter Horst, Rik; Horrobin, Matthew; Vernet, Joel; Finger, Gert; Groot, Paul; Kaper, Lex

    2008-07-01

    X-shooter is a new high-efficiency spectrograph observing the complete spectral range of 300-2500 nm in a single exposure, with a spectral resolving power R>5000. The instrument will be located at the Cassegrain focus of one of the VLT UTs and consists of three spectrographs: UV, VIS and Near-IR. This paper addresses the design, hardware realization and performance of the Near-IR spectrograph of the X-Shooter instrument and its components. Various optical, mechanical and cryogenic manufacturing and verification techniques are discussed. The cryogenic performance of replicated light weight gratings is presented. Bare aluminium mirrors are produced and polished to optical quality to preserve high shape accuracy at cryogenic conditions. Their manufacturing techniques and performance are both discussed. The cryogenic collimator and dispersion boxes, on which the optical components are mounted, feature integrated baffles for improved stiffness and integrated leaf springs to reduce tension on optical components, thereby challenging 5 axis simultaneous CNC milling capabilities. ASTRON Extreme Light Weighting is used for a key component to reduce the flexure of the cryogenic system; some key numbers and unique manufacturing experience for this component are presented. The method of integrated system design at cryogenic working temperatures and the resulting alignment-free integration are evaluated. Finally some key lab test results for the complete NIR spectrograph are presented.

  1. KiwiSpec - an advanced spectrograph for high resolution spectroscopy: optical design and variations

    NASA Astrophysics Data System (ADS)

    Barnes, Stuart I.; Gibson, Steve; Nield, Kathryn; Cochrane, Dave

    2012-09-01

    The KiwiSpec R4-100 is an advanced high resolution spectrograph developed by KiwiStar Optics, Industrial Research Ltd, New Zealand. The instrument is based around an R4 echelle grating and a 100mm collimated beam diameter. The optical design employs a highly asymmetric white pupil design, whereby the transfer collimator has a focal length only 1/3 that of the primary collimator. This allows the cross-dispersers (VPH gratings) and camera optics to be small and low cost while also ensuring a very compact instrument. The KiwiSpec instrument will be bre-fed and is designed to be contained in both thermal and/or vacuum enclosures. The instrument concept is highly exible in order to ensure that the same basic design can be used for a wide variety of science cases. Options include the possibility of splitting the wavelength coverage into 2 to 4 separate channels allowing each channel to be highly optimized for maximum eciency. CCDs ranging from smaller than 2K2K to larger than 4K4K can be accommodated. This allows good (3-4 pixel) sampling of resolving powers ranging from below 50,000 to greater than 100,000. Among the specic design options presented here will be a two-channel concept optimized for precision radial velocities, and a four-channel concept developed for the Gemini High- Resolution Optical Spectrograph (GHOST). The design and performance of a single-channel prototype will be presented elsewhere in these proceedings.

  2. KiwiSpec - an advanced spectrograph for high resolution spectroscopy: prototype design and performance

    NASA Astrophysics Data System (ADS)

    Gibson, Steve; Barnes, Stuart I.; Hearnshaw, John; Nield, Kathryn; Cochrane, Dave; Grobler, Deon

    2012-09-01

    A new advanced high resolution spectrograph has been developed by Kiwistar Optics of Industrial Research Ltd., New Zealand. The instrument, KiwiSpec R4-100, is bench-mounted, bre-fed, compact (0.75m by 1.5m footprint), and is well-suited for small to medium-sized telescopes. The instrument makes use of several advanced concepts in high resolution spectrograph design. The basic design follows the classical white pupil concept in an asymmetric implementation and employs an R4 echelle grating illuminated by a 100mm diameter collimated beam for primary dispersion. A volume phase holographic grating (VPH) based grism is used for cross-dispersion. The design also allows for up to four camera and detector channels to allow for extended wavelength coverage at high eciency. A single channel prototype of the instrument has been built and successfully tested with a 1m telescope. Targets included various spectrophotometric standard stars and several radial velocity standard stars to measure the instrument's light throughput and radial velocity capabilities. The prototype uses a 725 lines/mm VPH grism, an off-the-shelf camera objective, and a 2k×2k CCD. As such, it covers the wavelength range from 420nm to 660nm and has a resolving power of R ≍ 40,000. Spectrophotometric and precision radial velocity results from the on-sky testing period will be reported, as well as results of laboratory-based measurements. The optical design of KiwiSpec, and the various multi-channel design options, will be presented elsewhere in these proceedings.

  3. Efficient and affordable catadioptric spectrograph designs for 4MOST and Hector

    NASA Astrophysics Data System (ADS)

    Saunders, Will

    2014-08-01

    Spectrograph costs have become the limiting factor in multiplexed fiber-based spectroscopic instruments, because tens of millions of resolution elements (spectral x spatial) are now required. Catadioptric (Schmidt-like) designs allow faster cameras and hence reduced detector costs, and recent advances in aspheric lens production make the overall optics costs competitive with transmissive designs. Classic Schmidt designs suffer from obstruction losses caused by the detector being within the beam. A new catadioptric design puts the detector close to the spectrograph pupil, and hence largely in the shadow of the telescope top-end obstruction. The throughput is competitive with the best transmissive designs, and much better in the Blue, where it is usually most valuable. The design also has milder aspheres and is more compact than classic Schmidts, and avoids most of their operational difficulties. The fast cameras mean that with 15micron pixels, the PSF sampling is close to the Nyquist limit; this minimises the effects of read-noise, which for sky-limited observations, far outweighs any difference in throughput. It does introduce pixellation penalties; these are investigated and found to be modest. For 4MOST, low and high resolution designs are presented, with 300mm beams, 3 arms with f/1.3 cameras, and standard 61mm x 61mm detectors. Coverage is 380-930nm at R=5000-7000, or R~20000 in three smaller ranges. A switchable design is also presented. For Hector, a design is presented with 2 arms, 380-930nm coverage, and R=3000-4500; a 4- armed design with smaller beam-size and detectors is also presented. The designs are costed, and appear to represent excellent value.

  4. Interferometers and spectrographs on silicon-platform for astrophysics: trends of astrophotonics

    NASA Astrophysics Data System (ADS)

    Fernando, Harendra N. J.; Stoll, Andreas; Cvetojevic, Nick; Eisemann, René; Tharanga, Nuwan; Holmes, Christopher; Böhm, Michael; Roth, Martin M.; Haynes, Roger; Zimmermann, Lars

    2014-07-01

    We present results of comprehensive re-design of an arrayed waveguide grating (AWG)-based integrated photonic spectrograph (IPS), using Silica-on-Silicon (SOS) technology, to tailor specific performance parameters of interest to high-resolution (resolving power, R = λ/Δλ= 60,000) exoplanet astronomy and stellar seismology. The compactness, modularity, stability, replicability and small-lightweight-payload of the IPS are a few promising and innovative features in the design of high-resolution spectrographs for astronomy or other areas of sciences. The IPS is designed to resolve up to 646 spectral lines per spectral order, with a wavelength spacing of 25 pm, at a central wavelength of 1630 nm (Hband). The fabricated test waveguides have been stress engineered in order to compensate the inherent birefringence of SOS waveguides. The birefringence values of fabricated test structures were quantified, to be on the order 10-6 (theoretical value required to avoid the formation of ghost-images), through inscription of Bragg-gratings on straight waveguides and subsequent measurement of Bragg-reflection spectra. An interferometer system has been integrated with the SOS-IPS (in the same chip) for the characterization of phase errors of the waveguide array. Moreover, promising results of first fabricated key photonics components to form other complex integrated photonic circuits (IPCs), such as astro-interferometers, using silicon nitride-on-insulator (SNOI) technology are also presented. The fabricated IPCs include multimode interference based devices (power splitter/combiners, optical cross/bar-switches), directional-couplers with varying power ratios, Mach-Zehnder interferometers and an AWG. The first results of annealed, low-hydrogen SNOI based devices are promising and comparable to SOI and commercial devices, with device excess-loss less than 2 dB and under 1 dB/cm waveguide-loss in the IR-wavelength.

  5. Volume phase holographic gratings for the Subaru Prime Focus Spectrograph: performance measurements of the prototype grating set

    NASA Astrophysics Data System (ADS)

    Barkhouser, Robert H.; Arns, James; Gunn, James E.

    2014-08-01

    The Prime Focus Spectrograph (PFS) is a major instrument under development for the 8.2 m Subaru telescope on Mauna Kea. Four identical, fixed spectrograph modules are located in a room above one Nasmyth focus. A 55 m fiber optic cable feeds light into the spectrographs from a robotic fiber positioner mounted at the telescope prime focus, behind the wide field corrector developed for Hyper Suprime-Cam. The positioner contains 2400 fibers and covers a 1.3 degree hexagonal field of view. Each spectrograph module will be capable of simultaneously acquiring 600 spectra. The spectrograph optical design consists of a Schmidt collimator, two dichroic beamsplitters to separate the light into three channels, and for each channel a volume phase holographic (VPH) grating and a dual- corrector, modified Schmidt reimaging camera. This design provides a 275 mm collimated beam diameter, wide simultaneous wavelength coverage from 380 nm to 1.26 µm, and good imaging performance at the fast f/1.1 focal ratio required from the cameras to avoid oversampling the fibers. The three channels are designated as the blue, red, and near-infrared (NIR), and cover the bandpasses 380-650 nm (blue), 630-970 nm (red), and 0.94-1.26 µm (NIR). A mosaic of two Hamamatsu 2k×4k, 15 µm pixel CCDs records the spectra in the blue and red channels, while the NIR channel employs a 4k×4k, substrate-removed HAWAII-4RG array from Teledyne, with 15 µm pixels and a 1.7 µm wavelength cutoff. VPH gratings have become the dispersing element of choice for moderate-resolution astronomical spectro- graphs due their potential for very high diffraction efficiency, low scattered light, and the more compact instru- ment designs offered by transmissive dispersers. High quality VPH gratings are now routinely being produced in the sizes required for instruments on large telescopes. These factors made VPH gratings an obvious choice for PFS. In order to reduce risk to the project, as well as fully exploit the performance

  6. Design inputs for a high-performance high-resolution near-infrared spectrograph

    NASA Astrophysics Data System (ADS)

    Hinkle, Kenneth H.; Joyce, Richard R.; Najita, Joan R.

    2010-07-01

    The combination of immersion grating and infrared array detector technologies allows the construction of highresolution spectrographs in the near-infrared that have capabilities similar to those of optical spectrographs. It is possible, for instance, to design multi-object spectrographs with very large wavelength coverage and high throughput. We explored the science and functional drivers for these spectrograph designs. Several key inputs into the design are reviewed including risk, mechanical-optical trades, and operations. We discuss a design for a fixed configuration spectrograph with either 1.1 - 2.5 or 3 - 5 μm simultaneous wavelength coverage.

  7. WUVS spectrographs of World Space Observatory - Ultraviolet project

    NASA Astrophysics Data System (ADS)

    Savanov, Igor; Sachkov, Mikhail; Shustov, Boris M.; Shugarov, Andrey

    2016-07-01

    WSO-UV (World Space Observatory - Ultraviolet) project is an international space observatory designed for observations in the UV (115 - 320 nm). It includes a 170 cm aperture telescope capable of high-resolution spectroscopy, long slit low-resolution spectroscopy and deep UV and optical imaging. WUVS - the set of three ultraviolet spectrographs are regarded as the main instrument of «Spektr -UF» space mission. The spectrographs unit includes three channels and is intended for acquisition of spectrums of high (R=50000) and low (R=1000) resolution of the observed objects in the electromagnetic radiation's ultraviolet range (115-310 nm). We present the design philosophy of WUVS and summarize its key characteristics. We shall present the main properties of WUVS new structure and current status of its mockups and prototypes manufacturing.

  8. The Imaging Ultraviolet Spectrograph (IUVS) for the MAVEN Mission

    NASA Astrophysics Data System (ADS)

    McClintock, William E.; Schneider, Nicholas M.; Holsclaw, Gregory M.; Clarke, John T.; Hoskins, Alan C.; Stewart, Ian; Montmessin, Franck; Yelle, Roger V.; Deighan, Justin

    2015-12-01

    The Imaging Ultraviolet Spectrograph (IUVS) is one of nine science instruments aboard the Mars Atmosphere and Volatile and EvolutioN (MAVEN) spacecraft. MAVEN, launched in November 18, 2013 and arriving at Mars in September 2014, is designed to explore the planet's upper atmosphere and ionosphere and examine their interaction with the solar wind and solar ultraviolet radiation. IUVS is one of the most powerful spectrographs sent to another planet, with several key capabilities: (1) separate Far-UV & Mid-UV channels for stray light control, (2) a high resolution echelle mode to resolve deuterium and hydrogen emission, (3) internal instrument pointing and scanning capabilities to allow complete mapping and nearly-continuous operation, and (4) optimization for airglow studies.

  9. Design and Capabilities of the AAT/HERMES Spectrograph

    NASA Astrophysics Data System (ADS)

    de Silva, G. M.; Heijmans, J.; Gers, L.; Zucker, D.; Aao Hermes Team

    2012-08-01

    The High Efficiency and Resolution Multi-Element spectrograph (HERMES) currently under construction at the Australian Astronomical Observatory will be the next major instrument for the Anglo-Australian Telescope. It will provide a unique and powerful new facility for multi-object spectroscopy. HERMES uses the 2dF fibre positioning system to provide up to 392 multiplex capability over a 2 degree field of view. The spectrograph design includes 4 wavelength channels, each with VPH-gratings providing a nominal spectral resolving power of 28,000 and a high-resolution mode of 50,000. The initial wavelength channels are tailored for determining a large range of chemical elements suitable for chemical tagging, but allow for grating upgrades reconfigurable between 370 - 1000 nm. An overview of the project and expected performance based on the HERMES simulated data is presented.

  10. Performance and sensitivity of low-resolution spectrographs for LAMOST

    NASA Astrophysics Data System (ADS)

    Hou, Yonghui; Zhu, Yongtian; Hu, Zhongwen; Wang, Lei; Wang, Jianing

    2010-07-01

    The 16 low resolution spectrographs (LRS) have been successfully commissioned for the LAMOST. The LRS design employs a dual-beamed and bench-mounted, with large-beamed, fast Schmidt cameras and Volume Phase Holographic (VPH) transmission gratings. The design wavelength range is 370-900nm, at resolutions of R=1000and R=10000. Each spectrograph is fed by 250 fibers with 320 micron in diameter (corresponding 3.3 arcsec), composed of one F/4 Schmidt collimator, a dichroic beam-splitter, four VPH gratings, articulating Schmidt cameras that are optimized at blue band (370-590 nm) and red band (570-900 nm), and field lens near the focal plane service as the vacuum window of CCD detector cryogenic head. In this paper, we present the testing result of the LRS on the image quality, spectra resolution, efficiency and observing spectra.

  11. Optical design of the ESPRESSO spectrograph at VLT

    NASA Astrophysics Data System (ADS)

    Spanò, P.; Mégevand, D.; Herreros, J. M.; Zerbi, F. M.; Cabral, A.; Di Marcantonio, P.; Lovis, C.; Cristiani, S.; Rebolo, R.; Santos, N.; Pepe, F.

    2010-07-01

    ESPRESSO, a very high-resolution, high-efficiency, ultra-high stability, fiber-fed, cross-dispersed echelle spectrograph located in the Combined-Coudé focus of the VLT, has been designed to detect exo-planets with unprecedented radial velocity accuracies of 10 cm/sec over 20 years period. To increase spectral resolution, an innovative pupil slicing technique has been adopted, based onto free-form optics. Anamorphism has been added to increase resolution while keeping the physical size of the echelle grating within reasonable limits. Anamorphic VPH grisms will help to decrease detector size, while maximizing efficiency and inter-order separation. Here we present a summary of the optical design of the spectrograph and of expected performances.

  12. Optical design, performance, and tolerancing of an Offner imaging spectrograph

    NASA Astrophysics Data System (ADS)

    Ku, Hana; Kim, Seo Hyun; Kong, Hong Jin; Lee, Jun Ho

    2012-10-01

    We introduce a design of an Offner imaging spectrograph with its performance and tolerancing results. It is a traditional Offner spectrograph employing two concave mirrors and one convex reflective grating for dispersing light in the SWIR band (900~1700 nm). The optical system uses 25um-pitch pixels for the detector and the goal spectral sampling is 3.2nm. Its performance is analyzed in terms of MTFs, spot diagrams, and distortions - keystone and smile. This design focuses on the yaw(beta-tilt) sensitivity of the tertiary mirror as the compensator hence is expected to act as a performance-improving breakthrough for the entire system as the inverse sensitivity confirms it is the most sensitive component. The procedure of the inverse sensitivity evaluation is explained, and then budgeting the tolerances for each element for the practical production is described.

  13. BASIS: Bayfordbury single-object integral field spectrograph

    NASA Astrophysics Data System (ADS)

    Richards, Samuel; Martin, William; Campbell, David; Jones, Hugh; Bland-Hawthorn, Joss; Lawrence, Jon; Brinks, Elias; Bryant, Julia J.; Fogarty, Lisa; Gallaway, Mark; Goodwin, Michael; Leon-Saval, Sergio; Sarzi, Marc; Smith, Daniel J.

    2012-09-01

    We present an inexpensive (spectrograph (SBIG Self-Guiding Spectrograph) and a 37 optical fibre bundle integral field unit with each fibre having 50μm cores and a pitch of 125μm. It has an overall field-of-view of 40 arc seconds (2.6arcsec/core), a resolution of 9Å from 3995Å to 7170Å and an average system efficiency of 9%, yielding a signal-tonoise ratio of 10 for a 20min exposure of a 13mag/arcsec2 source. Still in commissioning, we present first light observations of Vega and M57.

  14. The infrared spectrograph during the SIRTF pre-definition phase

    NASA Technical Reports Server (NTRS)

    Houck, James R.

    1988-01-01

    A test facility was set up to evaluate back-illuminated impurity band detectors constructed for an infrared spectrograph to be used on the Space Infrared Telescope Facility (SIRTF). Equipment built to perform the tests on these arrays is described. Initial tests have been geared toward determining dark current and read noise for the array. Four prior progress reports are incorporated into this report. They describe the first efforts in the detector development and testing effort; testing details and a new spectrograph concept; a discussion of resolution issues raised by the new design; management activities; a review of computer software and testing facility hardware; and a review of the preamplifier constructed as well as a revised schematic of the detector evaluation facility.

  15. Optics characterization with compact EUV spectrophotometer

    NASA Astrophysics Data System (ADS)

    Blaschke, H.; Balasa, I.; Koch, L.; Starke, K.; Ristau, D.; Wies, C.; Lebert, R.; Bayer, A.; Barkusky, F.; Mann, K.

    2008-03-01

    The development of a novel compact EUV spectrophotometer will be presented. The device is capable of measuring reflectance and transmittance spectra of medium scale EUV-optics primary in the spectral range from 12nm to 21nm. Based on a new polychromatic measurement principle, the system uses the direct irradiation of a table-top EUV-source for illuminating the sample and a broad-band spectrograph for detecting the probe and reference beam. Samples can be investigated under different angles of incidence and in respect of lateral dependencies. Typical results of reflectivity investigations of Mo/Si-mirrors and transmitting foils will be shown and compared with reference measurements of certified institutes and calculations.

  16. The development of WIFIS: a wide integral field infrared spectrograph

    NASA Astrophysics Data System (ADS)

    Sivanandam, Suresh; Chou, Richard C. Y.; Moon, Dae-Sik; Ma, Ke; Millar-Blanchaer, Maxwell; Eikenberry, Stephen S.; Chun, Moo-Young; Kim, Sang Chul; Raines, Steven N.; Eisner, Joshua

    2012-09-01

    We present the current results from the development of a wide integral field infrared spectrograph (WIFIS). WIFIS offers an unprecedented combination of etendue and spectral resolving power for seeing-limited, integral field observations in the 0.9 - 1.8 μm range and is most sensitive in the 0.9 - 1.35 μ,m range. Its optical design consists of front-end re-imaging optics, an all-reflective image slicer-type, integral field unit (IFU) called FISICA, and a long-slit grating spectrograph back-end that is coupled with a HAWAII 2RG focal plane array. The full wavelength range is achieved by selecting between two different gratings. By virtue of its re-imaging optics, the spectrograph is quite versatile and can be used at multiple telescopes. The size of its field-of-view is unrivalled by other similar spectrographs, offering a 4.511x 1211 integral field at a 10-meter class telescope (or 2011 x 5011 at a 2.3-meter telescope). The use of WIFIS will be crucial in astronomical problems which require wide-field, two-dimensional spectroscopy such as the study of merging galaxies at moderate redshift and nearby star/planet-forming regions and supernova remnants. We discuss the final optical design of WIFIS, and its predicted on-sky performance on two reference telescope platforms: the 2.3-m Steward Bok telescope and the 10.4-m Gran Telescopio Canarias. We also present the results from our laboratory characterization of FISICA. IFU properties such as magnification, field-mapping, and slit width along the entire slit length were measured by our tests. The construction and testing of WIFIS is expected to be completed by early 2013. We plan to commission the instrument at the 2.3-m Steward Bok telescope at Kitt Peak, USA in Spring 2013.

  17. FIASCO: A new spectrograph at the University Observatory Jena

    NASA Astrophysics Data System (ADS)

    Mugrauer, M.; Avila, G.

    2009-05-01

    A new spectrograph (FIASCO) is in operation at the 0.9 m telescope of the University Observatory Jena. This article describes the characterization of the instrument and reports its first astronomical observations, among those lithium (6708 Å) detection in the atmosphere of young stars, and the simultaneous photometric and spectroscopic monitoring of variable stars. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University.

  18. V. M. Slipher and the Development of the Nebular Spectrograph

    NASA Astrophysics Data System (ADS)

    Thompson, L. A.

    2013-04-01

    Vesto Melvin Slipher was the first astronomer to clearly define the factors that determine the “speed” of a nebular spectrograph. This brief historical summary recounts the way these ideas developed and how Slipher's early work on galaxy Doppler shifts was so quickly extended in the 1930s when Milton Humason and Edwin Hubble at Mt. Wilson Observatory began to push the velocity-distance relationship to such a depth that no one could doubt its cosmological significance.

  19. Apollo 16 far-ultraviolet camera/spectrograph: Earth observations.

    PubMed

    Carruthers, G R; Page, T

    1972-09-01

    A far-ultraviolet camera/spectograph experiment was operated on the lunar surface during the Apollo 16 mission. Among the data obtained were images and spectra of the terrestrial atmosphere and geocorona in the wavelength range below 1600 angstroms. These gave the spatial distributions and relative intensities of emissions due to atomic hydrogen, atomic oxygen, molecular nitrogen, and other species-some observed spectrographically for the first time.

  20. The Goddard High Resolution Spectrograph: Instrument, goals, and science results

    NASA Technical Reports Server (NTRS)

    Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.

    1994-01-01

    The Goddard High Resolution Spectrograph (GHRS), currently in Earth orbit on the Hubble Space Telescope (HST), operates in the wavelength range 1150-3200 A with spectral resolutions (lambda/delta lambda) of approximately 2 x 10(exp 3), 2 x 10(exp 4), and 1 x 10(exp 3). The instrument and its development from inception, its current status, the approach to operations, representative results in the major areas of the scientific goals, and prospects for the future are described.

  1. First light results from the Hermes spectrograph at the AAT

    NASA Astrophysics Data System (ADS)

    Sheinis, Andrew; Barden, Sam; Birchall, Michael; Carollo, Daniela; Bland-Hawthorn, Joss; Brzeski, Jurek; Case, Scott; Cannon, Russell; Churilov, Vladimir; Couch, Warrick; Dean, Robert; De Silva, Gayandhi; D'Orazi, Valentina; Farrell, Tony; Fiegert, Kristin; Freeman, Kenneth; Frost, Gabriella; Gers, Luke; Goodwin, Michael; Gray, Doug; Heald, Ron; Heijmans, Jeroen; Jones, Damien; Keller, Stephan; Klauser, Urs; Kondrat, Yuriy; Lawrence, Jon; Lee, Steve; Mali, Slavko; Martell, Sarah; Mathews, Darren; Mayfield, Don; Miziarski, Stan; Muller, Rolf; Pai, Naveen; Patterson, Robert; Penny, Ed; Orr, David; Shortridge, Keith; Simpson, Jeffrey; Smedley, Scott; Smith, Greg; Stafford, Darren; Staszak, Nicholas; Vuong, Minh; Waller, Lewis; Wylie de Boer, Elizabeth; Xavier, Pascal; Zheng, Jessica; Zhelem, Ross; Zucker, Daniel

    2014-07-01

    The High Efficiency and Resolution Multi Element Spectrograph, HERMES is an facility-class optical spectrograph for the AAT. It is designed primarily for Galactic Archeology [21], the first major attempt to create a detailed understanding of galaxy formation and evolution by studying the history of our own galaxy, the Milky Way. The goal of the GALAH survey is to reconstruct the mass assembly history of the of the Milky Way, through a detailed spatially tagged abundance study of one million stars. The spectrograph is based at the Anglo Australian Telescope (AAT) and is fed by the existing 2dF robotic fiber positioning system. The spectrograph uses VPH-gratings to achieve a spectral resolving power of 28,000 in standard mode and also provides a high-resolution mode ranging between 40,000 to 50,000 using a slit mask. The GALAH survey requires a SNR greater than 100 for a star brightness of V=14. The total spectral coverage of the four channels is about 100nm between 370 and 1000nm for up to 392 simultaneous targets within the 2 degree field of view. Hermes has been commissioned over 3 runs, during bright time in October, November and December 2013, in parallel with the beginning of the GALAH Pilot survey starting in November 2013. In this paper we present the first-light results from the commissioning run and the beginning of the GALAH Survey, including performance results such as throughput and resolution, as well as instrument reliability. We compare the abundance calculations from the pilot survey to those in the literature.

  2. Hobby-Eberly Telescope low-resolution spectrograph: optical design

    NASA Astrophysics Data System (ADS)

    Cobos Duenas, Francisco J.; Tejada, Carlos; Hill, Gary J.; Perez G., F.

    1998-07-01

    The Hobby Eberly Telescope (HET) is a revolutionary large telescope of 9.2 meter aperture, which is currently undergoing commissioning at McDonald Observatory. First light was obtained on December 11, 1996. Scientific operations are expected in 1998. The Low Resolution Spectrograph (LRS, a collaboration between the University of Texas at Austin, the Instituto de Astronomia de la Universidad Nacional Autonoma de Mexico, Stanford University, Ludwig-Maximillians-Universitat, Munich and Georg-August-Universitat, Gottingen) is a high throughput, imaging spectrograph which rides on the HET tracker at prime focus. The LRS will be the first HET facility instrument. The unique nature of the HET has led to interesting optical design solutions for the LRS, aimed at high performance and simplicity. The LRS is a grism spectrograph with a refractive collimator and a catadioptric f/1.4 camera. The beam size is 140 mm, resulting in resolving powers between (lambda) /(Delta) (lambda) approximately 600 and 3000 with a 1 arcsec wide slit. The LRS optics were designed and partially fabricated at the IAUNAM. We present a description of the LRS specifications and optical design, and describe the manufacturing process.

  3. Hobby-Eberly Telescope low-resolution spectrograph: mechanical design

    NASA Astrophysics Data System (ADS)

    Hill, Gary J.; Nicklas, Harald E.; MacQueen, Phillip J.; Mitsch, Wolfgang; Wellem, Walter; Altmann, Werner; Wesley, Gordon L.; Ray, Frank B.

    1998-07-01

    The Hobby-Eberly Telescope (HET) is a revolutionary large telescope of 9.2 meter aperture, located in West Texas at McDonald Observatory. The Low Resolution Spectrograph [LRS, an international collaboration between the University of Texas at Austin (UT), the Instituto de Astronomia de la Universidad Nacional Autonoma de Mexico (IAUNAM), Stanford University, Ludwig-Maximillians-Universitat, Munich (USM), and Georg- August-Universitat, Gottingen (USG)] is a high throughput, imaging grism spectrograph which rides on the HET tracker at prime focus. The remote location and tight space and weight constraints make the LRS a challenging instrument, built on a limited budget. The mechanical design and fabrication were done in Germany, and the camera and CCD system in Texas. The LRS is a grism spectrograph with three modes of operation: imaging, longslit, and multi-object. Here we present a detailed description of the mechanical design of the LRS. Fabrication, assembly and testing of the LRS will be completed by mid 1998. First light for the LRS on the HET is expected in the summer of 1998.

  4. SPRAT: Spectrograph for the Rapid Acquisition of Transients

    NASA Astrophysics Data System (ADS)

    Piascik, A. S.; Steele, Iain A.; Bates, Stuart D.; Mottram, Christopher J.; Smith, R. J.; Barnsley, R. M.; Bolton, B.

    2014-07-01

    We describe the development of a low cost, low resolution (R ~ 350), high throughput, long slit spectrograph covering visible (4000-8000) wavelengths. The spectrograph has been developed for fully robotic operation with the Liverpool Telescope (La Palma). The primary aim is to provide rapid spectral classification of faint (V ˜ 20) transient objects detected by projects such as Gaia, iPTF (intermediate Palomar Transient Factory), LOFAR, and a variety of high energy satellites. The design employs a volume phase holographic (VPH) transmission grating as the dispersive element combined with a prism pair (grism) in a linear optical path. One of two peak spectral sensitivities are selectable by rotating the grism. The VPH and prism combination and entrance slit are deployable, and when removed from the beam allow the collimator/camera pair to re-image the target field onto the detector. This mode of operation provides automatic acquisition of the target onto the slit prior to spectrographic observation through World Coordinate System fitting. The selection and characterisation of optical components to maximise photon throughput is described together with performance predictions.

  5. The Hercules Échelle Spectrograph at Mt. John

    NASA Astrophysics Data System (ADS)

    Hearnshaw, J. B.; Barnes, S. I.; Kershaw, G. M.; Frost, N.; Graham, G.; Ritchie, R.; Nankivell, G. R.

    2002-03-01

    The High Efficiency and Resolution Canterbury University Large Échelle Spectrograph (HERCULES) a fibre-fed échelle spectrograph that was designed and built at the University of Canterbury and has been in operation at Mt. John University Observatory since April 2001.HERCULES receives light from the f/13.5 Cassegrain focus of the 1 m McLellan telescope. Resolving powers of R = 41 000, 70 000 and 82 000 are available. An R2 200 × 400 mm échelle grating provides dispersion and cross-dispersion uses a large BK7 prism in double pass. The wavelength coverage is designed to be 380-880 nm in a single exposure. The maximum detective quantum efficiency of the fibre, spectrograph and detector system is about 18% in 2 arc second seeing. High wavelength stability (to better than 10 ms-1 in radial velocity) is achieved by installing the whole instrument in a large vacuum tank at 2-4 torr and by there being no moving parts. The tank is in a thermally isolated and insulated environment. The paper describes the design philosophy of HERCULES and its performance during the first year of operation.

  6. Fibre Multi-Object Spectrograph (FMOS) for the Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Kimura, Masahiko; Maihara, Toshinori; Iwamuro, Fumihide; Akiyama, Masayuki; Tamura, Naoyuki; Dalton, Gavin B.; Takato, Naruhisa; Tait, Philip; Ohta, Kouji; Eto, Shigeru; Mochida, Daisaku; Elms, Brian; Kawate, Kaori; Kurakami, Tomio; Moritani, Yuuki; Noumaru, Junichi; Ohshima, Norio; Sumiyoshi, Masanao; Yabe, Kiyoto; Brzeski, Jurek; Farrell, Tony; Frost, Gabriella; Gillingham, Peter R.; Haynes, Roger; Moore, Anna M.; Muller, Rolf; Smedley, Scott; Smith, Greg; Bonfield, David G.; Brooks, Charles B.; Holmes, Alan R.; Curtis Lake, Emma; Lee, Hanshin; Lewis, Ian J.; Froud, Tim R.; Tosh, Ian A.; Woodhouse, Guy F.; Blackburn, Colin; Content, Robert; Dipper, Nigel; Murray, Graham; Sharples, Ray; Robertson, David J.

    2010-10-01

    Fibre Multi-Object Spectrograph (FMOS) is the first near-infrared instrument with a wide field of view capable of acquiring spectra simultaneously from up to 400 objects. It has been developed as a common-use instrument for the F/2 prime-focus of the Subaru Telescope. The field coverage of 30' diameter is achieved using a new 3-element corrector optimized in the near-infrared (0.9-1.8μm) wavelength range. Due to limited space at the prime-focus, we have had to develop a novel fibre positioner, called ``Echidna'', together with two OH-airglow suppressed spectrographs. FMOS consists of three subsystems: the prime focus unit for IR, the fibre positioning system/connector units, and the two spectrographs. After full systems integration, FMOS was installed on the telescope in late 2007. Many aspects of the performance were checked through various test and engineering observations. In this paper, we present the optical and mechanical components of FMOS, and show the results of our on-sky engineering observations to date.

  7. A wide-angle magnetic spectrograph of a novel design

    NASA Astrophysics Data System (ADS)

    Andrzejewski, Roch; Lucas, Julio; Guirao, Angel; Gordillo, Nuria; Boerma, Dirk

    2006-08-01

    At the 5 MV tandem accelerator of the CMAM we install a UHV magnetic spectrograph for the detection of scattered and recoiled ions. Its special feature is that the ions emerging from the sample are passing through a 4 nm thick DLC foil before entering the spectrograph. The secondary electrons emerging from this foil upon passage of an ion are focused on a two-dimensional position sensitive multi-channel plate (MCP) detector with delay-line read-out. From their impact position on this detector the direction of the ion is determined with a precision of 0.15° within an elliptical cone of 6° × 9°. The spectrograph, consisting of a 115° sector magnet with special shaped pole faces, focuses the ions onto a one-dimensional position sensitive MCP detector, also with delay-line read-out, in the focal plane of the magnet. The time delay of the coincident pulses in the first and second detector is measured so that the velocity v of the ion is known in addition to the magnetic rigidity mv/q, allowing determination of m/q. The energy resolution is determined by the straggling in the foil and amounts to ΔE/E ≈ 10-3 for 2 MeV α particles. Blocking patterns of scattered or recoiled ions can be measured in one run. Because of the ion identification implied in the system, recoil spectra can be generated with light ions used as projectile.

  8. Wide band focusing x-ray spectrograph with spatial resolution

    SciTech Connect

    Pikuz, S. A.; Douglass, J. D.; Shelkovenko, T. A.; Sinars, D. B.; Hammer, D. A.

    2008-01-15

    A new, wide spectral bandwidth x-ray spectrograph, the wide-bandwidth focusing spectrograph with spatial resolution (WB-FSSR), based on spherically bent mica crystals, is described. The wide bandwidth is achieved by combining three crystals to form a large aperture dispersive element. Since the WB-FSSR covers a wide spectral band, it is very convenient for application as a routine diagnostic tool in experiments in which the desired spectral coverage is different from one test to the next. The WB-FSSR has been tested in imploding wire-array experiments on a 1 MA pulsed power machine, and x-ray spectra were recorded in the 1-20 A spectral band using different orders of mica crystal reflection. Using a two mirror-symmetrically placed WB-FSSR configuration, it was also possible to distinguish between a real spectral shift and a shift of recorded spectral lines caused by the spatial distribution of the radiating plasma. A spectral resolution of about 2000 was demonstrated and a spatial resolution of {approx}100 {mu}m was achieved in the spectral band of 5-10 A in second order of mica reflection. A simple method of numerical analysis of spectrograph capability is proposed.

  9. Better flat-fielding for ground-based UV spectrographs

    NASA Astrophysics Data System (ADS)

    Kerber, Florian; Hanuschik, Reinhard; Moehler, Sabine; Smette, Alain; Smoker, Jonathan; Bourget, Pierre; Dwyer, Peter J.; Rotschädl, Michael

    2014-07-01

    A new technological development, the laser driven light source (LDLS), in which a laser excited plasma emits intense continuum radiation over a wide wavelength range from well below the atmospheric cut-off up to 800 nm, promises to greatly improve our ability to provide high quality flat-fields for astronomical spectrographs. Its particular strength lies in the ground-based ultraviolet (UV). We report on tests conducted with a LDLS using FORS2, UVES, X-Shooter and CRIRES at ESO's Very Large Telescope (VLT) in August 2013. Comparison with standard calibration sources such as halogen and deuterium lamps shows that with the LDLS flat-fields with a better balanced dynamic range and excellent signal to noise ratio can be achieved within short exposure times. This will enable higher quality science at the short wavelength end of existing spectrographs at the VLT. Furthermore the LDLS provides exceptional stability and long lifetime as important operational aspects. Optimised UV spectrographs such as the proposed CUBES (wavelength range 300-400 nm) project will be able to take full advantage of this development removing the long-standing limitation of signal to noise ratios of UV flat-fields.

  10. The near infrared camera for the Subaru Prime Focus Spectrograph

    NASA Astrophysics Data System (ADS)

    Smee, Stephen A.; Gunn, James E.; Golebiowski, Mirek; Barkhouser, Robert; Vivès, Sebastien; Pascal, Sandrine; Carr, Michael; Hope, Stephen C.; Loomis, Craig; Hart, Murdock; Sugai, Hajime; Tamura, Naoyuki; Shimono, Atsushi

    2014-08-01

    We present the detailed design of the near infrared camera for the SuMIRe (Subaru Measurement of Images and Redshifts) Prime Focus Spectrograph (PFS) being developed for the Subaru Telescope. The PFS spectrograph is designed to collect spectra from 2394 objects simultaneously, covering wavelengths that extend from 380 nm - 1.26 μm. The spectrograph is comprised of four identical spectrograph modules, with each module collecting roughly 600 spectra from a robotic fiber positioner at the telescope prime focus. Each spectrograph module will have two visible channels covering wavelength ranges 380 nm - 640 nm and 640 nm - 955 nm, and one near infrared (NIR) channel with a wavelength range 955 nm - 1.26 μm. Dispersed light in each channel is imaged by a 300 mm focal length, f/1.07, vacuum Schmidt camera onto a 4k x 4k, 15 µm pixel, detector format. For the NIR channel a HgCdTe substrate-removed Teledyne 1.7 μm cutoff device is used. In the visible channels, CCDs from Hamamatsu are used. These cameras are large, having a clear aperture of 300 mm at the entrance window, and a mass of ~ 250 kg. Like the two visible channel cameras, the NIR camera contains just four optical elements: a two-element refractive corrector, a Mangin mirror, and a field flattening lens. This simple design produces very good imaging performance considering the wide field and wavelength range, and it does so in large part due to the use of a Mangin mirror (a lens with a reflecting rear surface) for the Schmidt primary. In the case of the NIR camera, the rear reflecting surface is a dichroic, which reflects in-band wavelengths and transmits wavelengths beyond 1.26 μm. This, combined with a thermal rejection filter coating on the rear surface of the second corrector element, greatly reduces the out-of-band thermal radiation that reaches the detector. The camera optics and detector are packaged in a cryostat and cooled by two Stirling cycle cryocoolers. The first corrector element serves as the

  11. A near-infrared spectrograph for the Discovery Channel Telescope

    NASA Astrophysics Data System (ADS)

    Roe, H. G.; Dunham, E. W.; Bida, T. A.; Hall, J. C.; Degroff, W.

    2011-10-01

    Lowell Observatory is constructing the Discovery Channel Telescope (DCT) at Happy Jack, Arizona, approximately an hour from Lowell's main campus in Flagstaff, Arizona. The DCT is a 4.3-m optical/ infrared telescope. Construction of the telescope is complete and First Light of the DCT is planned for 2012Q2. In its initial configuration instruments will be co-mounted on a rotatable/selectable cube at the Cassegrain focus. Motorized deployable fold mirrors enable rapid switching amongst instruments. In the future the Nasmyth foci will be available for larger instruments as well. The first generation of instruments on DCT include: the Large Monolithic Imager (LMI), the Near-Infrared High-Throughput Spectrograph (NIHTS, pronounced "nights"), and the DeVeny optical spectrograph. The LMI contains a single large 6.1x6.1 K detector with a 12.5 arcmin2 FOV. NIHTS is a low resolution efficient near-infrared spectrograph and is the subject of this presentation. The DeVeny is Lowell's existing optical spectrograph with resolutions available between 500 and 4000. NIHTS is a low-resolution high-throughput infrared spectrograph covering 0.9-2.4 μm in a single fixed spectral setting at a resolution of »100. For simplicity and replicability NIHTS contains no moving parts. The science detector is a 10242 HAWAII-1 array. The fixed slit plate features an 80" long slit with several different slit widths (2,3,4 and 12 pixels) available along its length. The widest slit width is designed to allow accurate flux calibration, while the 3 and 4-pixel slits are closely matched to typical seeing at the DCT site (0.86" mean). Different resolutions will be rapidly selectable by dithering the telescope, and a typical observation is anticipated to involve a sequence of dithers both at the desired resolution and at SED resolution for calibration purposes. Offset guiding and wavefront sensing to control the active optics of the primary mirror are provided by the facility via deployable probes in

  12. Mouse Embryo Compaction.

    PubMed

    White, M D; Bissiere, S; Alvarez, Y D; Plachta, N

    2016-01-01

    Compaction is a critical first morphological event in the preimplantation development of the mammalian embryo. Characterized by the transformation of the embryo from a loose cluster of spherical cells into a tightly packed mass, compaction is a key step in the establishment of the first tissue-like structures of the embryo. Although early investigation of the mechanisms driving compaction implicated changes in cell-cell adhesion, recent work has identified essential roles for cortical tension and a compaction-specific class of filopodia. During the transition from 8 to 16 cells, as the embryo is compacting, it must also make fundamental decisions regarding cell position, polarity, and fate. Understanding how these and other processes are integrated with compaction requires further investigation. Emerging imaging-based techniques that enable quantitative analysis from the level of cell-cell interactions down to the level of individual regulatory molecules will provide a greater understanding of how compaction shapes the early mammalian embryo. PMID:27475854

  13. Reversible DNA compaction.

    PubMed

    González-Pérez, Alfredo

    2014-01-01

    In this review we summarize and discuss the different methods we can use to achieve reversible DNA compaction in vitro. Reversible DNA compaction is a natural process that occurs in living cells and viruses. As a result these process long sequences of DNA can be concentrated in a small volume (compacted) to be decompacted only when the information carried by the DNA is needed. In the current work we review the main artificial compacting agents looking at their suitability for decompaction. The different approaches used for decompaction are strongly influenced by the nature of the compacting agent that determines the mechanism of compaction. We focus our discussion on two main artificial compacting agents: multivalent cations and cationic surfactants that are the best known compacting agents. The reversibility of the process can be achieved by adding chemicals like divalent cations, alcohols, anionic surfactants, cyclodextrins or by changing the chemical nature of the compacting agents via pH modifications, light induced conformation changes or by redox-reactions. We stress the relevance of electrostatic interactions and self-assembly as a main approach in order to tune up the DNA conformation in order to create an on-off switch allowing a transition between coil and compact states. The recent advances to control DNA conformation in vitro, by means of molecular self-assembly, result in a better understanding of the fundamental aspects involved in the DNA behavior in vivo and serve of invaluable inspiration for the development of potential biomedical applications. PMID:24444152

  14. Attaining m s-1 level intrinsic Doppler precision with RHEA, a low-cost single-mode spectrograph

    NASA Astrophysics Data System (ADS)

    Feger, Tobias; Ireland, Michael J.; Schwab, Christian; Bento, Joao; Bacigalupo, Carlos; Coutts, David W.

    2016-08-01

    We present RHEA, a compact and inexpensive single-mode spectrograph which is built to exploit the capabilities of modest-sized telescopes in an economic way. The instrument is fed by up to seven optical waveguides with the aim of achieving an efficient and modal-noise-free unit, suitable for attaining extreme Doppler precision. The cross-dispersed layout features a wavelength coverage from 430-650 nm, with spectral resolution of R ˜75,000. When coupled to small telescopes using fast tip/tilt control, our instrument is well-suited to sensitive spectroscopy. Example science cases are accurate radial velocity studies of low to intermediate-mass giant stars with the purpose of searching for giant plants and using asteroseismology to simultaneously measure the host star parameters. In this paper we describe the final instrument design and present first results from testing the internal stability.

  15. The Hobby-Eberly Telescope Low Resolution Spectrograph

    NASA Astrophysics Data System (ADS)

    Hill, G. J.; MacQueen, P. J.; Nicklas, H.; Cobos D., F. J.; Tejada, C.; Mitsch, W.; Wolf, M. J.

    1998-12-01

    The Hobby-Eberly Telescope (HET) is a revolutionary large telescope of 9.2 meter aperture, located in West Texas at McDonald Observatory. First light was obtained on December 11, 1996. Scientific operations are expected in the spring of 1999. The Low Resolution Spectrograph (LRS, an international collaboration between Texas, UNAM, Stanford, Munich and Goettingen) is a high throughput, imaging spectrograph which rides on the HET tracker at prime focus. The LRS will be the first HET facility instrument. The remote location and tight space and weight constraints make the LRS a challenging instrument, built on a limited budget. The optics were partially constructed in Mexico at IAUNAM, the mechanics in Germany, and the camera and CCD system in Texas. The LRS is a grism spectrograph with a number of modes of operation: imaging, longslit, and multi-object. The field of view from the HET is 4-arcminutes in diameter, and the LRS will have a 13-slitlet Multi Object Spectroscopy (MOS) unit covering this field. The MOS unit is described in a separate paper. Resolutions between lambda / {delta lambda } = 500 and 3000 with a 1-arcsec. wide slit will be achieved with a variety of grisms, of which two can be carried by the instrument at any one time. The CCD is a Ford Aerospace 1024x3096 device with 15 micron pixels, and the image scale is approximately 0.25 arcsec. per pixel. We will present a detailed description of the LRS, and provide an overview of the optical and mechanical aspects of its design. Fabrication and assembly of the LRS will be completed by the end of 1998. First light on the HET is expected shortly thereafter.

  16. CAFE: Calar Alto Fiber-fed Échelle spectrograph

    NASA Astrophysics Data System (ADS)

    Aceituno, J.; Sánchez, S. F.; Grupp, F.; Lillo, J.; Hernán-Obispo, M.; Benitez, D.; Montoya, L. M.; Thiele, U.; Pedraz, S.; Barrado, D.; Dreizler, S.; Bean, J.

    2013-04-01

    We present here CAFE, the Calar Alto Fiber-fed Échelle spectrograph, a new instrument built at the Centro Astronomico Hispano Alemán (CAHA). CAFE is a single-fiber, high-resolution (R ~ 70 000) spectrograph, covering the wavelength range between 3650-9800 Å. It was built on the basis of the common design for Échelle spectrographs. Its main aim is to measure radial velocities of stellar objects up to V ~ 13-14 mag with a precision as good as a few tens of m s-1. To achieve this goal the design was simplified at maximum, removing all possible movable components, the central wavelength is fixed, as is the wavelength coverage; there is no filter wheel, etc. Particular care was taken with the thermal and mechanical stability. The instrument is fully operational and publically accessible at the 2.2 m telescope of the Calar Alto Observatory. In this article we describe (i) the design, summarizing its manufacturing phase; (ii) characterize the main properties of the instrument; (iii) describe the reduction pipeline; and (iv) show the results from the first light and commissioning runs. The preliminar results indicate that the instrument fulfills the specifications and can achieve the planned goals. In particular, the results show that the instrument is more efficient than anticipated, reaching a signal-to-noise of ~20 for a stellar object as faint as V ~ 14.5 mag in ~2700 s integration time. The instrument is a wonderful machine for exoplanetary research (by studying large samples of possible systems cotaining massive planets), galactic dynamics (highly precise radial velocities in moving groups or stellar associations), or astrochemistry.

  17. Design of the KOSMOS oil-coupled spectrograph camera lenses

    NASA Astrophysics Data System (ADS)

    O'Brien, Thomas P.; Derwent, Mark; Martini, Paul; Poczulp, Gary

    2014-07-01

    We present the design details of oil-coupled lens groups used in the KOSMOS spectrograph camera. The oil-coupled groups use silicone rubber O-rings in a unique way to accurately center lens elements with high radial and axial stiffness while also allowing easy assembly. The O-rings robustly seal the oil within the lens gaps to prevent oil migration. The design of an expansion diaphragm to compensate for differential expansion due to temperature changes is described. The issues of lens assembly, lens gap shimming, oil filling and draining, bubble mitigation, material compatibility, mechanical inspection, and optical testing are discussed.

  18. Updated Status and Performance for the Cosmic Origins Spectrograph

    NASA Astrophysics Data System (ADS)

    Taylor, Joanna M.; De Rosa, Gisella; Debes, John H.; Ely, Justin; Fix, Mees B.; Fox, Andrew; Jedrzejewski, Robert I.; Lockwood, Sean A.; Monroe, TalaWanda R.; Oliveira, Cristina M.; Peeples, Molly S.; Penton, Steven V.; Plesha, Rachel; Proffitt, Charles R.; Roman-Duval, Julia; Sahnow, David J.; Sonnentrucker, Paule; Walborn, Nolan R.; White, James

    2016-06-01

    The Cosmic Origins Spectrograph (COS) was installed on the Hubble Space Telescope (HST) in May 2009. COS is designed to perform high-sensitivity medium- and low-resolution spectroscopy of astronomical objects in the far-ultraviolet (FUV) and near-ultraviolet (NUV) wavelength regimes. We present updates on the time-dependent sensitivities of both the NUV and FUV detectors. Additionally, we discuss the appearance and mitigation of transient, isolated regions of increased count rates on the COS FUV detector called “hot spots”. We also present updates to the COS calibration pipeline, CalCOS, that provide improvements to COS data products.

  19. CCD readout electronics for the Subaru Prime Focus Spectrograph

    NASA Astrophysics Data System (ADS)

    Hope, Stephen C.; Gunn, James E.; Loomis, Craig P.; Fitzgerald, Roger E.; Peacock, Grant O.

    2014-07-01

    The following paper details the design for the CCD readout electronics for the Subaru Telescope Prime Focus Spectrograph (PFS). PFS is designed to gather spectra from 2394 objects simultaneously, covering wavelengths that extend from 380 nm to 1260 nm. The spectrograph is comprised of four identical spectrograph modules, each collecting roughly 600 spectra. The spectrograph modules provide simultaneous wavelength coverage over the entire band through the use of three separate optical channels: blue, red, and near infrared (NIR). A camera in each channel images the multi-object spectra onto a 4k × 4k, 15 μm pixel, detector format. The two visible cameras use a pair of Hamamatsu 2k × 4k CCDs with readout provided by custom electronics, while the NIR camera uses a single Teledyne HgCdTe 4k × 4k detector and Teledyne's ASIC Sidecar to read the device. The CCD readout system is a custom design comprised of three electrical subsystems - the Back End Electronics (BEE), the Front End Electronics (FEE), and a Pre-amplifier. The BEE is an off-the-shelf PC104 computer, with an auxiliary Xilinx FPGA module. The computer serves as the main interface to the Subaru messaging hub and controls other peripheral devices associated with the camera, while the FPGA is used to generate the necessary clocks and transfer image data from the CCDs. The FEE board sets clock biases, substrate bias, and CDS offsets. It also monitors bias voltages, offset voltages, power rail voltage, substrate voltage and CCD temperature. The board translates LVDS clock signals to biased clocks and returns digitized analog data via LVDS. Monitoring and control messages are sent from the BEE to the FEE using a standard serial interface. The Pre-amplifier board resides behind the detectors and acts as an interface to the two Hamamatsu CCDs. The Pre-amplifier passes clocks and biases to the CCDs, and analog CCD data is buffered and amplified prior to being returned to the FEE. In this paper we describe the

  20. Spectrographic studies: Electron induced luminescence in optical materials

    NASA Technical Reports Server (NTRS)

    Romanko, J.; Miles, J. K.; Cheever, P. R.

    1971-01-01

    The spectral luminescence induced in UV grade sapphire, MgF2 and LiF2, three fused silicas, and three Corning glasses, by 1/2, 1, 2, and 3 MeV electrons was recorded. In the wavelength range from the LiF UV cutoff to the near visible, a plane-grating spectrograph with photographic recording at resolutions of 0.8 and 1.6 nm was utilized. Qualitative results based on relative density tracings of seven of the nine materials obtained from preliminary plates are given.

  1. Working model of a gossamer membrane spectrographic space telescope

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.; Ritter, Joe; Valliant, John

    2009-08-01

    The nineteenth century Fraunhofer primary objective grating (POG) telescope has been redesigned with a secondary spectrometer. The POG is embossed on a membrane and placed at an angle of grazing exodus relative to a conventional spectrographic telescope. The result is a new type of telescope that disambiguates overlapping spectra and can capture spectral flux from all objects over its free spectral range, nearly 40°. For space deployment, the ribbon-shaped membrane can be stowed as a cylinder under a rocket fairing for launch and deployed in space from a cylindrical drum. Any length up to kilometer scale could be contemplated.

  2. Two-Dimensional Spectroscopy with the Cosmic Origins Spectrograph

    NASA Astrophysics Data System (ADS)

    Penton, Steven V.; Sahnow, D.; France, K.

    2011-05-01

    The circular aperture of HSTs' Cosmic Origins Spectrograph (COS) is 2.5" in diameter, but transmission extends out to a 4" diameter. The NUV MAMA and the FUV microchannel plates image the sky over the full extent of the transmission. The cross-dispersion plate scale of the NUV channel is 0.02" and is 0.1" for the FUV channel. In this presentation we will discuss the capabilities and limitations of performing two-dimensional spectroscopy, in the cross-dispersion direction, with COS. In particular, we will discuss FUV detector effects, such as fixed pattern noise, gain sag, and Y walk, and the latest techniques for their correction.

  3. Mechanics of tissue compaction.

    PubMed

    Turlier, Hervé; Maître, Jean-Léon

    2015-12-01

    During embryonic development, tissues deform by a succession and combination of morphogenetic processes. Tissue compaction is the morphogenetic process by which a tissue adopts a tighter structure. Recent studies characterized the respective roles of cells' adhesive and contractile properties in tissue compaction. In this review, we formalize the mechanical and molecular principles of tissue compaction and we analyze through the prism of this framework several morphogenetic events: the compaction of the early mouse embryo, the formation of the fly retina, the segmentation of somites and the separation of germ layers during gastrulation.

  4. Elliptical X-ray analyzer spectrograph application to a laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Tanaka, Tina J.; Palmer, Merrill A.; Henke, Burton L.

    1985-08-01

    A preliminary experimental study was conducted on the application of an elliptical analyzer spectrograph to X-ray diagnostics of pulsed plasmas. This spectrograph was designed to record a range of 100-2000 eV X-rays on calibrated Kodak RAR-21497 film. Using point calibrations and theoretical models, the spectrograph efficiency was predicted. Basic spectrograph geometry and photographic calibrations are presented in companion papers. A 20 J, 6 ns duration Nd:glass laser pulse was focussed upon planar targets of gold, aluminum, teflon and boron carbide. Sample spectra for line and X-ray yields analysis are presented.

  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 Å to 23000 Å. 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. Absolute calibration of space-resolving soft X-ray spectrograph for plasma diagnostics

    NASA Astrophysics Data System (ADS)

    Yoshikawa, M.; Okamoto, Y.; Kawamori, E.; Watanabe, Y.; Watabe, C.; Yamaguchi, N.; Tamano, T.

    2001-07-01

    A grazing incidence flat-field soft X-ray (20-350 Å) spectrograph was constructed and applied for impurity diagnostics in the GAMMA 10 fusion plasma. The spectrograph consisted of a limited height entrance slit, an aberration-corrected concave grating, a microchannel-plate intensified detector and an instant camera/a high speed solid state camera. An absolute calibration experiment for the SX spectrograph was performed at the Photon Factory in the High Energy Accelerator Research Organization with monitoring the incident synchrotron beam intensity by using an absolutely calibrated XUV silicon photodiode. From the results of absolute calibration of the spectrograph, the radiation loss from the plasma was obtained.

  7. Integral field spectroscopy with the Gemini Near-Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Allington-Smith, Jeremy R.; Dubbeldam, Cornelis M.; Content, Robert; Dunlop, Colin J.; Robertson, David J.; Elias, Jay; Rodgers, Bernadette; Turner, James E.

    2004-09-01

    The Astronomical Instrumentation Group (AIG) of the University of Durham has recently completed an integral field unit (IFU) for use on the Gemini-South telescope with the Gemini Near-Infrared Spectrograph (GNIRS) built by the National Optical Astronomy Observatories (NOAO, USA). When the IFU is deployed remotely inside the instrument cryostat, GNIRS is converted into an integral field spectrograph with a field of 5 × 3 arcsec2 and spatial sampling of 0.15 × 0.15 arcsec2, optimised for 1-2.5μm but operable up to 5μm. We present summaries of the design and construction and results from laboratory testing. We also show results obtained at the telescope where a throughput of 90% was measured at 2.5μm, and show that this is consistent with predictions of a simple model where surface scattering is the dominant loss mechanism. The throughput data are well fit by the roughness measured in the laboratory. Finally, we show a few examples of astrophysical data from the commissioning run in April 2004.

  8. EMIR: cryogenic NIR multi-object spectrograph for GTC

    NASA Astrophysics Data System (ADS)

    Balcells, Marc; Guzman, R.; Patron, J.; Aragon-Salamanca, Alfonso; Azcue, J.; Ballester Lluch, Jose A.; Barroso, M. T.; Beigbeder, F.; Brau-Nogue, S.; Cardiel, N.; Carter, Dave; Diaz-Garcia, Jose J.; de la Fuente, E.; Fuentes, F. Javier; Fragoso-Lopez, Ana B.; Gago, Fernando; Gallego, J.; Gomez-Elvira, J.; Heredero, J. C.; Jones, Damien J.; Lopez, J. C.; Luke, P.; Manescau, Antonio; Munoz, T.; Peletier, R. F.; Pello, R.; Picat, Jean P.; Robertson, David J.; Rodriguez, J. A.; Serrano, Angel; Sharples, Ray M.; Zamorano, J.

    2000-08-01

    EMIR is a near-IR, multi-slit camera-spectrograph under development for the 10m GTC on La Palma. It will deliver up to 45 independent R equals 3500-4000 spectra of sources over a field of view of 6 feet by 3 feet, and allow NIR imaging over a 6 foot by 6 foot FOV, with spatial sampling of 0.175 inch/pixel. The prime science goal of the instrument is to open K-band, wide field multi-object spectroscopy on 10m class telescopes. Science applications range from the study of star-forming galaxies beyond z equals 2, to observations of substellar objects and dust-enshrouded star formation regions. Main technological challenges include the large optics, the mechanical and thermal stability and the need to implement a mask exchange mechanism that does not require warming up the spectrograph. EMIR is begin developed by the Instituto de Astrofisica de Canarias, the Instituto Nacional de Tecnica Aeroespacial, the Universidad Complutense de Madrid, the Observatoire Midi-Pyrennees, and the University of Durham. Currently in its Preliminary Design phase, EMIR is expected to start science operation in 2004.

  9. Modelling the application of integrated photonic spectrographs to astronomy

    NASA Astrophysics Data System (ADS)

    Harris, R. J.; Allington-Smith, J. R.

    2012-09-01

    One of the well-known problems of producing instruments for Extremely Large Telescopes is that their size (and hence cost) scales rapidly with telescope aperture. To try to break this relation alternative new technologies have been proposed, such as the use of the Integrated Photonic Spectrograph (IPS). Due to their diraction limited nature the IPS is claimed to defeat the harsh scaling law applying to conventional instruments. The problem with astronomical applications is that unlike conventional photonics, they are not usually fed by diraction limited sources. This means in order to retain throughput and spatial information the IPS will require multiple Arrayed Waveguide Gratings (AWGs) and a photonic lantern. We investigate the implications of these extra components on the size of the instrument. We also investigate the potential size advantage of using an IPS as opposed to conventional monolithic optics. To do this, we have constructed toy models of IPS and conventional image sliced spectrographs to calculate the relative instrument sizes and their requirements in terms of numbers of detector pixels. Using these models we can quantify the relative size/cost advantage for dierent types of instrument, by varying dierent parameters e.g. multiplex gain and spectral resolution. This is accompanied by an assessment of the uncertainties in these predictions, which may prove crucial for the planning of future instrumentation for highly-multiplexed spectroscopy.

  10. MSE spectrograph optical design: a novel pupil slicing technique

    NASA Astrophysics Data System (ADS)

    Spanò, P.

    2014-07-01

    The Maunakea Spectroscopic Explorer shall be mainly devoted to perform deep, wide-field, spectroscopic surveys at spectral resolutions from ~2000 to ~20000, at visible and near-infrared wavelengths. Simultaneous spectral coverage at low resolution is required, while at high resolution only selected windows can be covered. Moreover, very high multiplexing (3200 objects) must be obtained at low resolution. At higher resolutions a decreased number of objects (~800) can be observed. To meet such high demanding requirements, a fiber-fed multi-object spectrograph concept has been designed by pupil-slicing the collimated beam, followed by multiple dispersive and camera optics. Different resolution modes are obtained by introducing anamorphic lenslets in front of the fiber arrays. The spectrograph is able to switch between three resolution modes (2000, 6500, 20000) by removing the anamorphic lenses and exchanging gratings. Camera lenses are fixed in place to increase stability. To enhance throughput, VPH first-order gratings has been preferred over echelle gratings. Moreover, throughput is kept high over all wavelength ranges by splitting light into more arms by dichroic beamsplitters and optimizing efficiency for each channel by proper selection of glass materials, coatings, and grating parameters.

  11. Astrophotonic micro-spectrographs in the era of ELTs

    NASA Astrophysics Data System (ADS)

    Blind, N.; Le Coarer, E.; Kern, P.; Bland-Hawthorn, J.

    2014-08-01

    The next generation of Extremely Large Telescopes (ELT), with diameters up to 39 meters, will start opera- tion in the next decade and promises new challenges in the development of instruments. The growing field of astrophotonics (the use of photonic technologies in astronomy) can partly solve this problem by allowing mass production of fully integrated and robust instruments combining various optical functions, with the potential to reduce the size, complexity and cost of instruments. In this paper, we focus on developments in integrated micro-spectrographs and their potential for ELTs. We take an inventory of the identified technologies currently in development, and compare the performance of the different concepts. We show that in the current context of single-mode instruments, integrated spectrographs making use of, e.g., a photonic lantern can be a solution to reach the desired performance. However, in the longer term, there is a clear need to develop multimode devices to improve overall the throughput and sensitivity, while decreasing the instrument complexity.

  12. First science observations with the ACES echelle spectrograph

    NASA Astrophysics Data System (ADS)

    Reynolds, Robert O.; Lloyd-Hart, Michael

    2004-09-01

    The use of spectrographs with telescopes having high order adaptive optics (AO) systems offers the possibility of achieving near diffraction-limited spectral resolution with ground-based telescopes, as well as important advantages for instrument design. The use of an optical fiber to couple the instrument to the telescope affords additional advantages such as flexibility in the placement of the instrument and improved homogeneity of the input illumination function. In the case of Steward Observatory's Adaptively Coupled Echelle Spectrograph (ACES), the instrument is normally coupled to the telescope with an 8 micron diameter near single-mode optical fiber, although the instrument can be used at fixed focus locations without the fiber for telescopes so equipped. The use of a fiber coupler results in the phenomenon known as 'modal noise', where the transmission of multiple modes in the fiber leads to a wavelength-dependent variation in illumination that limits flat fielding precision. We have largely eliminated this effect through the use of an automated fiber stretcher device. We report here on improvements to the fiber feed optics and on interim observations made with the instrument at a conventional telescope not equipped with adaptive optics.

  13. The Rapid Acquisition Imaging Spectrograph Experiment (RAISE) Sounding Rocket Investigation

    NASA Astrophysics Data System (ADS)

    Laurent, Glenn T.; Hassler, Donald M.; Deforest, Craig; Slater, David D.; Thomas, Roger J.; Ayres, Thomas; Davis, Michael; de Pontieu, Bart; Diller, Jed; Graham, Roy; Michaelis, Harald; Schuele, Udo; Warren, Harry

    2016-03-01

    We present a summary of the solar observing Rapid Acquisition Imaging Spectrograph Experiment (RAISE) sounding rocket program including an overview of the design and calibration of the instrument, flight performance, and preliminary chromospheric results from the successful November 2014 launch of the RAISE instrument. The RAISE sounding rocket payload is the fastest scanning-slit solar ultraviolet imaging spectrograph flown to date. RAISE is designed to observe the dynamics and heating of the solar chromosphere and corona on time scales as short as 100-200ms, with arcsecond spatial resolution and a velocity sensitivity of 1-2km/s. Two full spectral passbands over the same one-dimensional spatial field are recorded simultaneously with no scanning of the detectors or grating. The two different spectral bands (first-order 1205-1251Å and 1524-1569Å) are imaged onto two intensified Active Pixel Sensor (APS) detectors whose focal planes are individually adjusted for optimized performance. RAISE reads out the full field of both detectors at 5-10Hz, recording up to 1800 complete spectra (per detector) in a single 6-min rocket flight. This opens up a new domain of high time resolution spectral imaging and spectroscopy. RAISE is designed to observe small-scale multithermal dynamics in Active Region (AR) and quiet Sun loops, identify the strength, spectrum and location of high frequency waves in the solar atmosphere, and determine the nature of energy release in the chromospheric network.

  14. X-shooter near infra-red spectrograph cryogenic design

    NASA Astrophysics Data System (ADS)

    Roelfsema, Ronald; Albers, Peter; Lizon, Jean-Louis; van Dael, Pieter; Elswijk, Eddy; Groot, Paul; Hanenburg, Hiddo; Kragt, Jan; Navarro, Ramon; Tromp, Niels; Wulterkens, Gerben

    2008-07-01

    X-shooter is a high-efficiency spectrograph capable of simultaneously observing the complete spectral range of 300- 2500 nm. The instrument will be located at the Cassegrain focus of one of the VLT UTs. To allow sky back ground limited observations the 120 kg Optical Bench of the NIR Spectrograph and the HAWAII-2RG detector are cooled to 105 K and 82 K respectively. To ensure vibrationless operation the cooling is performed by a LN2 bath-cryostat. The thermal stability requirements for the Optical Box are very tight (order of 100 mK) considering that the NIR-cryostat is subject to telescope movement and LN2 level variations. Large glass optics are limiting the cooldown. To speed up the cooldown the cooling concept of the Optical Box includes the utilization of LN2 heat exchangers. To avoid asymptotic stabilizing times the Optical Box is cooled below the operating temperature. When the optics reach a temperature slightly above the operating temperature the temperature of the Optical Box is quickly brought back to stabilize the optics. Dedicated controllers, strapping and heaters are used for temperature stabilization during steady state. A cryostat hold time of 24 hours with the minimum amount of LN2 in view of the tight mass budget requires strict control of the power budget and careful control of the design margins. This is ensured by precise modeling of the temperature behavior. The thermal model is compared with the actual measured thermal behavior.

  15. CUBES: cassegrain U-band Brazil-ESO spectrograph

    NASA Astrophysics Data System (ADS)

    Barbuy, B.; Bawden Macanhan, V.; Bristow, P.; Castilho, B.; Dekker, H.; Delabre, B.; Diaz, M.; Gneiding, C.; Kerber, F.; Kuntschner, H.; La Mura, G.; Maciel, W.; Meléndez, J.; Pasquini, L.; Pereira, C. B.; Petitjean, P.; Reiss, R.; Siqueira-Mello, C.; Smiljanic, R.; Vernet, J.

    2014-11-01

    CUBES is a high-efficiency, medium-resolution ( R˜20,000) ground based UV (300-400 nm) spectrograph, to be installed in the cassegrain focus of one of ESO's VLT unit telescopes in 2017/18. The CUBES project is a joint venture between ESO and IAG/USP, and LNA/MCTI. CUBES will provide access to a wealth of new and relevant information for stellar as well as extragalactic sources. Main science cases include the study of beryllium and heavy elements in metal-poor stars, the direct determination of carbon, nitrogen and oxygen abundances by study of molecular bands in the UV range, as well as the study of active galactic nuclei and the quasar absorption lines. With a streamlined modern instrument design, high efficiency dispersing elements and UV-sensitive detectors, it will give a significant gain in sensitivity over existing ground based medium-high resolution spectrographs, enabling vastly increased sample sizes accessible to the astronomical community. We present here a brief overview of the project including the status, science cases and a discussion of the design options.

  16. Ultra-Compact, Superconducting Spectrometer-on-a-Chip at Submillimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Chattopadhyay, Goutam; Zmuidzinas, Jonas; Bradford, Charles M.; Leduc, Henry G.; Day, Peter K.; Swenson, Loren; Hailey-Dunsheath, Steven; O'Brient, Roger C.; Padin, Stephen; Shirokoff, Erik D.; McKenney, Christopher; Reck, Theodore; Siles, Jose V.; Barry, Peter; Doyle, Simon; Mauskopf, Philip; Llombart, Nuria; Kovacs, Attila; Marrone, Dan P.

    2013-01-01

    Small size, wide spectral bandwidth, and highly multiplexed detector readout are required to develop powerful multi-beam spectrometers for high-redshift observations. Currently available spectrometers at these frequencies are large and bulky. The grating sizes for these spectrometers are prohibitive. This fundamental size issue is a key limitation for space-based spectrometers for astrophysics applications. A novel, moderate-resolving-power (R-700), ultra-compact spectrograph-on-a-chip for millimeter and submillimeter wavelengths is the solution.

  17. Prime Focus Spectrograph (PFS): A Very Wide-Field, Massively Multi-Object, Optical and Near-Infrared Fiber-Fed Spectrograph on the Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Tamura, N.; PFS Collaboration

    2016-10-01

    PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared fiber spectrograph: 2400 reconfigurable fibers are distributed in the 1.3 deg. field of view at the prime focus of the Subaru Telescope. The spectrograph system has blue, red, and near-infrared cameras to simultaneously observe spectra from 380 nm to 1260 nm in one exposure. The project is now entering the construction phase, aiming at starting system integration and commissioning in 2017-2018, and science operation in 2019.

  18. The Rosetta Alice Ultraviolet Spectrograph Investigation: The First UV Spectrograph to Reach a Comet—Results Overview

    NASA Astrophysics Data System (ADS)

    Stern, S. Alan; Parker, Joel Wm.; A'Hearn, Michael F.; Bertaux, Jean-Loup; Feaga, Lori M.; Feldman, Paul D.; Keeney, Brian A.; Noonan, John; Schindhelm, Eric; Steffl, Andrew; Weaver, Harold A.

    2016-10-01

    Numerous scientific results have been obtained from the exploration of comet 67P/Churyumov-Gerasimenko by the ESA/NASA Rosetta mission. The Alice far/extreme-UV spectrograph aboard Rosetta is one of three US instruments provided by NASA to this mission; it is the first UV spectrograph to reach any comet. We will summarize the main results obtained by the Alice instrument to date, including both surface and coma studies. Notable results we will highlight will include: the discovery of electron impact excitation as the dominant UV emission mechanism near the comet, the detection of molecular oxygen at surprisingly high abundance in the coma, the lack of strong water-ice signatures on the comet's surface during the approach to perihelion, numerous results concerning cometary outbursts, and a large database of systematics relating to atomic and molecular species abundances as the comet approached and then receded from the Sun over a span of two year surrounding the comet's August 2015 perihelion.

  19. Compaction properties of isomalt.

    PubMed

    Bolhuis, Gerad K; Engelhart, Jeffrey J P; Eissens, Anko C

    2009-08-01

    Although other polyols have been described extensively as filler-binders in direct compaction of tablets, the polyol isomalt is rather unknown as pharmaceutical excipient, in spite of its description in all the main pharmacopoeias. In this paper the compaction properties of different types of ispomalt were studied. The types used were the standard product sieved isomalt, milled isomalt and two types of agglomerated isomalt with a different ratio between 6-O-alpha-d-glucopyranosyl-d-sorbitol (GPS) and 1-O-alpha-d-glucopyranosyl-d-mannitol dihydrate (GPM). Powder flow properties, specific surface area and densities of the different types were investigated. Compactibility was investigated by compression of the tablets on a compaction simulator, simulating the compression on high-speed tabletting machines. Lubricant sensitivity was measured by compressing unlubricated tablets and tablets lubricated with 1% magnesium stearate on an instrumented hydraulic press. Sieved isomalt had excellent flow properties but the compactibility was found to be poor whereas the lubricant sensitivity was high. Milling resulted in both a strong increase in compactibility as an effect of the higher surface area for bonding and a decrease in lubricant sensitivity as an effect of the higher surface area to be coated with magnesium stearate. However, the flow properties of milled isomalt were too bad for use as filler-binder in direct compaction. Just as could be expected, agglomeration of milled isomalt by fluid bed agglomeration improved flowability. The good compaction properties and the low lubricant sensitivity were maintained. This effect is caused by an early fragmentation of the agglomerated material during the compaction process, producing clean, lubricant-free particles and a high surface for bonding. The different GPS/GPM ratios of the agglomerated isomalt types studied had no significant effect on the compaction properties. PMID:19327398

  20. Stabilization of compactible waste

    SciTech Connect

    Franz, E.M.; Heiser, J.H. III; Colombo, P.

    1990-09-01

    This report summarizes the results of series of experiments performed to determine the feasibility of stabilizing compacted or compactible waste with polymers. The need for this work arose from problems encountered at disposal sites attributed to the instability of this waste in disposal. These studies are part of an experimental program conducted at Brookhaven National Laboratory (BNL) investigating methods for the improved solidification/stabilization of DOE low-level wastes. The approach taken in this study was to perform a series of survey type experiments using various polymerization systems to find the most economical and practical method for further in-depth studies. Compactible dry bulk waste was stabilized with two different monomer systems: styrene-trimethylolpropane trimethacrylate (TMPTMA) and polyester-styrene, in laboratory-scale experiments. Stabilization was accomplished by wetting or soaking compactible waste (before or after compaction) with monomers, which were subsequently polymerized. Three stabilization methods are described. One involves the in-situ treatment of compacted waste with monomers in which a vacuum technique is used to introduce the binder into the waste. The second method involves the alternate placement and compaction of waste and binder into a disposal container. In the third method, the waste is treated before compaction by wetting the waste with the binder using a spraying technique. A series of samples stabilized at various binder-to-waste ratios were evaluated through water immersion and compression testing. Full-scale studies were conducted by stabilizing two 55-gallon drums of real compacted waste. The results of this preliminary study indicate that the integrity of compacted waste forms can be readily improved to ensure their long-term durability in disposal environments. 9 refs., 10 figs., 2 tabs.

  1. Hobby-Eberly Telescope low-resolution spectrograph

    NASA Astrophysics Data System (ADS)

    Hill, Gary J.; Nicklas, Harald E.; MacQueen, Phillip J.; Tejada, Carlos; Cobos Duenas, Francisco J.; Mitsch, Wolfgang

    1998-07-01

    The Hobby-Eberly Telescope (HET) is a revolutionary large telescope of 9.2 meter aperture, located in West Texas at McDonald Observatory. First light was obtained on December 11, 1996. The start of scientific operations is expected in the late summer of 1998. The Low Resolution Spectrograph [LRS, an international collaboration between the University of Texas at Austin (UT), the Instituto de Astronomia de la Universidad Nacional Autonoma de Mexico (IAUNAM), Stanford University, Ludwig-Maximillians-Universitat, Munich (USM), and Georg- August-Universitat, Gottingen (USG)] is a high throughput, imaging spectrograph which rides on the HET tracker at prime focus. The LRS will be the first HET facility instrument. The remote location and the tight space and weight constraints make the LRS a challenging instrument, built on a limited budget. The optics were partially constructed in Mexico at IAUNAM, the mechanics in Germany, and the camera and CCD system in Texas. The LRS is a grism spectrograph with three modes of operation: imaging, longslit, and multi-object. The field of view of the HET is 4 arcmin in diameter, and the LRS will have a 13-slitlet Multi Object Spectroscopy (MOS) unit covering this field. The MOS unit is based on miniature components and is remotely configurable under computer control. Resolving powers between R equals (lambda) /(Delta) (lambda) approximately 600 and 3000 with a 1 arcsecond wide slit will be achieved with a variety of grisms, of which two can be carried by the instrument at any one time. The CCD is a Ford Aerospace 3072 X 1024 device with 15 micrometer pixels, and the image scale is approximately 0.25 arcsec per pixel. Here we present a detailed description of the LRS, and provide an overview of the optical and mechanical aspects of its design (which are discussed in detail elsewhere in these proceedings). Fabrication, assembly, and testing of the LRS will be completed by mid 1998. First light for the LRS on the HET is expected in the

  2. The Ultraviolet Spectrograph on the Europa Mission (Europa-UVS)

    NASA Astrophysics Data System (ADS)

    Retherford, K. D.; Gladstone, R.; Greathouse, T. K.; Steffl, A.; Davis, M. W.; Feldman, P. D.; McGrath, M. A.; Roth, L.; Saur, J.; Spencer, J. R.; Stern, S. A.; Pope, S.; Freeman, M. A.; Persyn, S. C.; Araujo, M. F.; Cortinas, S. C.; Monreal, R. M.; Persson, K. B.; Trantham, B. J.; Versteeg, M. H.; Walther, B. C.

    2015-12-01

    NASA's Europa multi-flyby mission is designed to provide a diversity of measurements suited to enrich our understanding of the potential habitability of this intriguing ocean world. The Europa mission's Ultraviolet Spectrograph, Europa-UVS, is the sixth in a series of successful ultraviolet imaging spectrographs (Rosetta-Alice, New Horizons Pluto-Alice, LRO-LAMP) and, like JUICE-UVS (now under Phase B development), is largely based on the most recent of these to fly, Juno-UVS. Europa-UVS observes photons in the 55-210 nm wavelength range, at moderate spectral and spatial resolution along a 7.5° slit. Three distinct apertures send light to the off-axis telescope mirror feeding the long-slit spectrograph: i) a main entrance airglow port is used for most observations (e.g., airglow, aurora, surface mapping, and stellar occultations); ii) a high-spatial-resolution port consists of a small hole in an additional aperture door, and is used for detailed observations of bright targets; and iii) a separate solar port allows for solar occultations, viewing at a 60° offset from the nominal payload boresight. Photon event time-tagging (pixel list mode) and programmable spectral imaging (histogram mode) allow for observational flexibility and optimal science data management. As on Juno-UVS, the effects of penetrating electron radiation on electronic parts and data quality are mitigated through contiguous shielding, filtering of pulse height amplitudes, management of high-voltage settings, and careful use of radiation-hard parts. The science goals of Europa-UVS are to: 1) Determine the composition & chemistry, source & sinks, and structure & variability of Europa's atmosphere, from equator to pole; 2) Search for and characterize active plumes in terms of global distribution, structure, composition, and variability; 3) Explore the surface composition & microphysics and their relation to endogenic & exogenic processes; and 4) Investigate how energy and mass flow in the Europa

  3. Precision spectroscopy with a frequency-comb-calibrated solar spectrograph

    NASA Astrophysics Data System (ADS)

    Doerr, H.-P.

    2015-06-01

    The measurement of the velocity field of the plasma at the solar surface is a standard diagnostic tool in observational solar physics. Detailed information about the energy transport as well as on the stratification of temperature, pressure and magnetic fields in the solar atmosphere are encoded in Doppler shifts and in the precise shape of the spectral lines. The available instruments deliver data of excellent quality and precision. However, absolute wavelength calibration in solar spectroscopy was so far mostly limited to indirect methods and in general suffers from large systematic uncertainties of the order of 100 m/s. During the course of this thesis, a novel wavelength calibration system based on a laser frequency comb was deployed to the solar Vacuum Tower Telescope (VTT), Tenerife, with the goal of enabling highly accurate solar wavelength measurements at the level of 1 m/s on an absolute scale. The frequency comb was developed in a collaboration between the Kiepenheuer-Institute for Solar Physics, Freiburg, Germany and the Max Planck Institute for Quantum Optics, Garching, Germany. The efforts cumulated in the new prototype instrument LARS (Lars is an Absolute Reference Spectrograph) for solar precision spectroscopy which is in preliminary scientific operation since~2013. The instrument is based on the high-resolution echelle spectrograph of the VTT for which feed optics based on single-mode optical fibres were developed for this project. The setup routinely achieves an absolute calibration accuracy of 60 cm/s and a repeatability of 2.5 cm/s. An unprecedented repeatability of only 0.32 cm/s could be demonstrated with a differential calibration scheme. In combination with the high spectral resolving power of the spectrograph of 7x10^5 and virtually absent internal scattered light, LARS provides a spectral purity and fidelity that previously was the domain of Fourier-transform spectrometers only. The instrument therefore provides unique capabilities for

  4. A fast new cadioptric design for fiber-fed spectrographs

    NASA Astrophysics Data System (ADS)

    Saunders, Will

    2012-09-01

    The next generation of massively multiplexed multi-object spectrographs (DESpec, SUMIRE, BigBOSS, 4MOST, HECTOR) demand fast, efficient and affordable spectrographs, with higher resolutions (R = 3000-5000) than current designs. Beam-size is a (relatively) free parameter in the design, but the properties of VPH gratings are such that, for fixed resolution and wavelength coverage, the effect on beam-size on overall VPH efficiency is very small. For alltransmissive cameras, this suggests modest beam-sizes (say 80-150mm) to minimize costs; while for cadioptric (Schmidt-type) cameras, much larger beam-sizes (say 250mm+) are preferred to improve image quality and to minimize obstruction losses. Schmidt designs have benefits in terms of image quality, camera speed and scattered light performance, and recent advances such as MRF technology mean that the required aspherics are no longer a prohibitive cost or risk. The main objections to traditional Schmidt designs are the inaccessibility of the detector package, and the loss in throughput caused by it being in the beam. With expected count rates and current read-noise technology, the gain in camera speed allowed by Schmidt optics largely compensates for the additional obstruction losses. However, future advances in readout technology may erase most of this compensation. A new Schmidt/Maksutov-derived design is presented, which differs from previous designs in having the detector package outside the camera, and adjacent to the spectrograph pupil. The telescope pupil already contains a hole at its center, because of the obstruction from the telescope top-end. With a 250mm beam, it is possible to largely hide a 6cm × 6cm detector package and its dewar within this hole. This means that the design achieves a very high efficiency, competitive with transmissive designs. The optics are excellent, as least as good as classic Schmidt designs, allowing F/1.25 or even faster cameras. The principal hardware has been costed at $300K per

  5. Design and Build a Compact Raman Sensor for Identification of Chemical Composition

    NASA Technical Reports Server (NTRS)

    Garcia, Christopher S.; Abedin, M. Nurul; Ismail, Syed; Sharma, Shiv K.; Misra, Anupam K.; Sandford, Stephen P.; Elsayed-Ali, Hani

    2008-01-01

    A compact remote Raman sensor system was developed at NASA Langley Research Center. This sensor is an improvement over the previously reported system, which consisted of a 532 nm pulsed laser, a 4-inch telescope, a spectrograph, and an intensified charge-coupled devices (CCD) camera. One of the attractive features of the previous system was its portability, thereby making it suitable for applications such as planetary surface explorations, homeland security and defense applications where a compact portable instrument is important. The new system was made more compact by replacing bulky components with smaller and lighter components. The new compact system uses a smaller spectrograph measuring 9 x 4 x 4 in. and a smaller intensified CCD camera measuring 5 in. long and 2 in. in diameter. The previous system was used to obtain the Raman spectra of several materials that are important to defense and security applications. Furthermore, the new compact Raman sensor system is used to obtain the Raman spectra of a diverse set of materials to demonstrate the sensor system's potential use in the identification of unknown materials.

  6. Ultraviolet Spectrograph Concepts for the Outer Planet Flagship Mission

    NASA Astrophysics Data System (ADS)

    Retherford, Kurt D.; Stern, A.; Slater, D. C.; Gladstone, R.; Davis, M. W.; Parker, J. W.; Steffl, A. J.; Greathouse, T. K.; Cunningham, N. J.; Spencer, J. R.

    2008-09-01

    SwRI's Alice line of ultraviolet spectrographs (UVS) is founded on a lightweight, low power, and highly capable and versatile instrument design. With generally small changes in detector photocathode, detector pixel size, slit size and shape, optical coatings, pinhole aperture implementations, and other minor tweaks we've found a wide variety of applications for the Alice design, to date, at comets (Rosetta/Alice), Pluto (New Horizons/Alice), Luna (LRO/LAMP), and Jupiter (Juno/UVS). The SwRI UVS heritage includes very broad experience and strong performance to date on the Rosetta (Phase E; successful Mars flyby), New Horizons (Phase E; successful Jupiter flyby), LRO (Phase D; mated to the spacecraft), and Juno (Phase C) missions. Alice's high capability, low resource requirements, and our experience with Juno-based radiation environment and NH-based outer solar system environment requirements make this UVS a good choice for the Outer Planet Flagship mission concepts.

  7. Data Reduction Pipeline for the MMT and Magellan Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Chilingarian, Igor; Beletsky, Yuri; Moran, Sean; Brown, Warren; McLeod, Brian; Fabricant, Daniel

    2015-04-01

    We describe the new spectroscopic data reduction pipeline for the multi-object MMT/Magellan Infrared Spectrograph. The pipeline is implemented in idl as a stand-alone package and is publicly available in both stable and development versions. We describe novel algorithms for sky subtraction and correction for telluric absorption. We demonstrate that our sky subtraction technique reaches the Poisson limit set by the photon statistics. Our telluric correction uses a hybrid approach by first computing a correction function from an observed stellar spectrum, and then differentially correcting it using a grid of atmosphere transmission models for the target airmass value. The pipeline provides a sufficient level of performance for real time reduction and thus enables data quality control during observations. We reduce an example dataset to demonstrate the high data reduction quality.

  8. Sound spectrographic analysis of pain cry in preterm infants.

    PubMed

    Michelsson, K; Järvenpää, A L; Rinne, A

    1983-07-01

    Sound spectrographic cry analysis was performed on 302 cries of 48 preterm infants born at 30-37 gestational weeks. The cries were recorded during the first week of life and thereafter weekly until the infants were discharged. The control series comprised 54 cries from 27 fullterm healthy infants. The results showed that the cries of the smallest prematures compared with the controls were shorter, more high-pitched, and included bi-phonation and glide more often. The cry characteristics changed with increasing conceptual age and the older the child the more the cry pattern resembled that of the fullterm. The cries of the preterm infants when they had reached 38 conceptual weeks were similar to those of newly born fullterm infants. The results indicate that the gestational age should be taken into consideration in cry analysis. PMID:6884256

  9. Cosmic Origins Spectrograph: On-Orbit Performance of Target Acquisitions

    NASA Astrophysics Data System (ADS)

    Penton, Steven V.

    2010-07-01

    COS is a slit-less spectrograph with a very small aperture (R=1.2500). To achieve the desired wavelength accuracies, HST+COS must center the target to within 0.100 of the center of the aperture for the FUV channel, and 0.0400 for NUV. During SMOV and early Cycle 17 we fine-tuned the COS target acquisition (TA) procedures to exceed this accuracy for all three COS TA modes; NUV imaging, NUV spectroscopic, and FUV spectroscopic. In Cycle 17, we also adjusted the COSto- FGS offsets in the SIAF file. This allows us to recommend skipping the time consuming ACQ/SEARCH in cases where the target coordinates are well known. Here we will compare the on-orbit performance of all COS TA modes in terms of centering accuracy, efficiency, and required signal-to-noise (S/N).

  10. Extreme ultraviolet spectrograph ATM experiment S082B.

    PubMed

    Bartoe, J D; Brueckner, G E; Purcell, J D; Tousey, R

    1977-04-01

    The extreme ultraviolet, double-dispersion, photographic spectrograph, Apollo Telescope Mount (ATM) Experiment S082B on Skylab is described. Novel features were the use of a predisperser grating with a ruling whose spacing varied approximately linearly with distance for the purpose of increasing the instrument speed by reducing the astigmatism and a photoelectric servo-system to stabilize to 1 sec of arc the solar image at various near-limb positions. The 970-3940-A range was covered in two sections with effective lambda/Deltalambda congruent with 30,000 from 1100 A to 1970 A. The spatial resolution was 2 x 60 solar sec of arc. During the Skylab mission 6400 exposures were made with the instrument pointed by an astronaut at selected and recorded'solar positions.

  11. GNOSIS: an OH suppression unit for near-infrared spectrographs

    NASA Astrophysics Data System (ADS)

    Ellis, S. C.; Bland-Hawthorn, J.; Lawrence, J. S.; Bryant, J.; Haynes, R.; Horton, A.; Lee, S.; Leon-Saval, S.; Löhmannsröben, Hans-Gerd; Mladenoff, J.; O'Byrne, J.; Rambold, W.; Roth, M.; Trinh, C.

    2010-07-01

    GNOSIS is an OH suppression unit to be used in conjunction with existing spectrographs. The OH suppression is achieved using fibre Bragg gratings (FBGs), and will deliver the darkest near-infrared background of any ground-based instrument. Laboratory and on-sky tests demonstrate that FBGs can suppress OH lines by 30dB whilst maintaing > 90% throughput between the lines, resulting in a 4 mag decrease in the background. In the first implementation GNOSIS will feed IRIS2 on the AAT. It will consist of a seven element lenslet array, covering 1.4" on the sky, and will suppress the 103 brightest OH lines between 1.47 and 1.70 μm. Future upgrades will include J-band suppression and implementation on an 8m telescope.

  12. Spectrographic analysis of pain cry in neonates with cleft palate.

    PubMed

    Michelsson, K; Sirviö, P; Koivisto, M; Sovijärvi, A; Wasz-Höckert, O

    1975-01-01

    52 phonations of 13 cleft palate neonates were analyzed by sound spectrographic methods. 17 phonetical attributes were included in the study and the first signal after the pain stimulus was analyzed. The cries of the cleft palate infants were compared with the crying of 75 normal babies of the same age. No change in the fundamental frequency, melody type and duration of the cries was seen in association with these anatomical defects. Two of the characteristics studied, vibrato and the 'tonal pit', occurred significantly more often in cries of the cleft palate infants than in cries of the control series. The changes in the qualities seen in association with cleft palate and/or cleft lip do not mimic the abnormalities produced by brain damage.

  13. Telescope baffle performance for Lyman Far Ultraviolet Spectrographic Explorer

    NASA Astrophysics Data System (ADS)

    Morbey, Christopher; Hutchings, J. B.

    1993-07-01

    The Lyman Far Ultraviolet Spectrographic Explorer telescope is a Wolter type II glancing incidence design with an aperture of 64 cm. Because the spacecraft is required to guide on stars fainter than m(v) = 16, a visible light baffle is necessary to protect the FOV from the stray light that results from out-of-field bright sources. Such a baffle system is described here. Total point-source transmittances are computed for incident beams in the range 0-70 deg. Estimates for background brightness on the detector are made for the contribution from direct sunlight and earthshine. Scattering from the black surfaces of the baffle, the vanes, and diffraction at the structure's edges are taken into consideration.

  14. Raman Imaging with a Fiber-Coupled Multichannel Spectrograph

    PubMed Central

    Schmälzlin, Elmar; Moralejo, Benito; Rutowska, Monika; Monreal-Ibero, Ana; Sandin, Christer; Tarcea, Nicolae; Popp, Jürgen; Roth, Martin M.

    2014-01-01

    Until now, spatially resolved Raman Spectroscopy has required to scan a sample under investigation in a time-consuming step-by-step procedure. Here, we present a technique that allows the capture of an entire Raman image with only one single exposure. The Raman scattering arising from the sample was collected with a fiber-coupled high-performance astronomy spectrograph. The probe head consisting of an array of 20 × 20 multimode fibers was linked to the camera port of a microscope. To demonstrate the high potential of this new concept, Raman images of reference samples were recorded. Entire chemical maps were received without the need for a scanning procedure. PMID:25420149

  15. Spectrographic Polarimeter and Method of Recording State of Polarity

    NASA Technical Reports Server (NTRS)

    Sparks, William B. (Inventor)

    2015-01-01

    A single-shot real-time spectropolarimeter for use in astronomy and other sciences that captures and encodes some or all of the Stokes polarization parameters simultaneously using only static, robust optical components with no moving parts is described. The polarization information is encoded onto the spectrograph at each wavelength along the spatial dimension of the 2D output data array. The varying embodiments of the concept include both a two-Stokes implementation (in which any two of the three Stokes polarization parameters are measured) and a full Stokes implementation (in which all three of the Stokes polarization parameters are measured), each of which is provided in either single beam or dual beam forms.

  16. Updated Status and Performance of the Space Telescope Imaging Spectrograph

    NASA Astrophysics Data System (ADS)

    Wolfe, Michael A.; Dixon, W. V.; Mason, E.; Proffitt, C.; Aloisi, A.; Oliveira, C.; Bohlin, R. C.; Osten, R.; Bostroem, K. A.; Zheng, W.; Pascucci, I.; Niemi, S.; York, B.; Sonnentracker, P.; Diaz, R.; Ely, J. C.

    2011-05-01

    A description is provided of the overall performance of the Space Telescope Imaging Spectrograph after Cycle 17 and through the first half of Cycle 18. Most aspects of performance are still found to be consistent with extrapolations of the trends seen during Cycle 17 calibrations. Many of the characteristics of the instrument have changed over time, and we present here an update on its current performance based on the latest Cycle 18 calibration observations. We discuss changes in the CCD and MAMA dark currents, provide updates on the sensitivity of STIS modes, echelle blaze function, discuss changes, if any, in number of hot pixels, flat fields, charge transfer inefficiency, read noise, and spurious charge.

  17. Status of RAISE, the Rapid Acquisition Imaging Spectrograph Experiment

    NASA Astrophysics Data System (ADS)

    Laurent, Glenn T.; Hassler, D. M.; DeForest, C.; Ayres, T. R.; Davis, M.; De Pontieu, B.; Schuehle, U.; Warren, H.

    2013-07-01

    The Rapid Acquisition Imaging Spectrograph Experiment (RAISE) sounding rocket payload is a high speed scanning-slit imaging spectrograph designed to observe the dynamics and heating of the solar chromosphere and corona on time scales as short as 100 ms, with 1 arcsec spatial resolution and a velocity sensitivity of 1-2 km/s. The instrument is based on a new class of UV/EUV imaging spectrometers that use only two reflections to provide quasi-stigmatic performance simultaneously over multiple wavelengths and spatial fields. The design uses an off-axis parabolic telescope mirror to form a real image of the sun on the spectrometer entrance aperture. A slit then selects a portion of the solar image, passing its light onto a near-normal incidence toroidal grating, which re-images the spectrally dispersed radiation onto two array detectors. Two full spectral passbands over the same one-dimensional spatial field are recorded simultaneously with no scanning of the detectors or grating. The two different spectral bands (1st-order 1205-1243Å and 1526-1564Å) are imaged onto two intensified Active Pixel Sensor (APS) detectors whose focal planes are individually adjusted for optimized performance. The telescope and grating are coated with B4C to enhance short wavelength (2nd order) reflectance, enabling the instrument to record the brightest lines between 602-622Å and 761-780Å at the same time. RAISE reads out the full field of both detectors at 5-10 Hz, allowing us to record over 1,500 complete spectral observations in a single 5-minute rocket flight, opening up a new domain of high time resolution spectral imaging and spectroscopy. We present an overview of the project, a summary of the maiden flight results, and an update on instrument status.Abstract (2,250 Maximum Characters): The Rapid Acquisition Imaging Spectrograph Experiment (RAISE) sounding rocket payload is a high speed scanning-slit imaging spectrograph designed to observe the dynamics and heating of the solar

  18. Scientific Design of a High Contrast Integral Field Spectrograph for the Subaru Telescope

    NASA Technical Reports Server (NTRS)

    McElwain, Michael W.

    2012-01-01

    Ground based telescopes equipped with adaptive optics systems and specialized science cameras are now capable of directly detecting extrasolar planets. We present the scientific design for a high contrast integral field spectrograph for the Subaru Telescope. This lenslet based integral field spectrograph will be implemented into the new extreme adaptive optics system at Subaru, called SCExAO.

  19. A Student Assembled Spectrograph with a CCD Detector to Assist with Students' Understanding of Spectrometry

    ERIC Educational Resources Information Center

    Grove, T. T.; Masters, M. F.

    2007-01-01

    To help students develop an understanding of the proper use and function of spectrographs and monochromators we describe a student-assembled spectrograph using a "webcam" detector. The apparatus also works well as a low-cost demonstration, helping students make connections between an atomic spectrum observed by eye and a plot of the relative…

  20. A new high-speed solar radio spectrograph for meter and decameter wavelengths

    NASA Technical Reports Server (NTRS)

    Mosier, S. R.; Fainberg, J.

    1974-01-01

    The design and characteristics of a high resolution, digital solar spectrograph are discussed. The spectrometer operates in the 10 to 80 MHz range. The primary considerations in the design of the spectrograph were: (1) optimun sensitivity, (2) wide dynamic range, (3) flexibility in time and frequency resolution, and (4) modern data handling techniques with a simple computer interface.

  1. Galactic Archaeology with the Subaru Prime Focus Spectrograph

    NASA Astrophysics Data System (ADS)

    Chiba, Masashi; Cohen, Judith; Wyse, Rosemary

    2015-08-01

    We present our Galactic Archaeology survey plan with the Prime Focus Spectrograph (PFS) for Subaru. PFS is a massively-multiplexed, fiber-fed optical and near-infrared 3-arm spectrograph (N_fiber = 2,400, 380 < lambda < 1260 nm, 1.3 degree diameter hexagonal field, low- and medium-resolution modes of R = 2,000-3,000 and 5,000, respectively), offering us unique opportunities in survey astronomy. Following successful design reviews, the instrument is now under construction with first light anticipated in 2018. In the Galactic Archaeology program, for which we expect to have about 100 nights over 5 years, radial velocities and chemical abundances of stars in the Milky Way and M31 will be used to infer the past assembly histories of these galaxies and the structure of their dark matter halos. Data will be secured for numerous stars in the Galactic thick-disk, halo and tidal streams as faint as V = 22 mag, including stars with V < 20 mag to complement the goals of the Gaia mission. A medium-resolution mode with R = 5,000 to be implemented in the red arm will allow the measurement of multiple alpha-element abundances and more precise velocities for Galactic stars, elucidating the detailed chemo-dynamical structure and evolution of each of the main stellar components of the Milky Way Galaxy and of its dwarf spheroidal galaxies. The M31 campaign will target red giant branch stars with 21.5 < V < 22.5 mag, obtaining radial velocities and metallicities over an unprecedented large area of its stellar halo. In synergy with these planned PFS survey, the coordinated imaging surveys with Hyper Suprime Cam are going on over wide areas of the Galactic satellites and the M31 halo, based on the combination of broad-band and narrow-band filters to separate candidate giants from foreground dwarfs as spectroscopic targets.

  2. DMD-based programmable wide field spectrograph for Earth observation

    NASA Astrophysics Data System (ADS)

    Zamkotsian, Frédéric; Lanzoni, Patrick; Liotard, Arnaud; Viard, Thierry; Costes, Vincent; Hébert, Philippe-Jean

    2015-03-01

    In Earth Observation, Universe Observation and Planet Exploration, scientific return could be optimized in future missions using MOEMS devices. In Earth Observation, we propose an innovative reconfigurable instrument, a programmable wide-field spectrograph where both the FOV and the spectrum could be tailored thanks to a 2D micromirror array (MMA). For a linear 1D field of view (FOV), the principle is to use a MMA to select the wavelengths by acting on intensity. This component is placed in the focal plane of a first grating. On the MMA surface, the spatial dimension is along one side of the device and for each spatial point, its spectrum is displayed along the perpendicular direction: each spatial and spectral feature of the 1D FOV is then fully adjustable dynamically and/or programmable. A second stage with an identical grating recomposes the beam after wavelengths selection, leading to an output tailored 1D image. A mock-up has been designed, fabricated and tested. The micromirror array is the largest DMD in 2048 x 1080 mirrors format, with a pitch of 13.68μm. A synthetic linear FOV is generated and typical images have been recorded o at the output focal plane of the instrument. By tailoring the DMD, we could modify successfully each pixel of the input image: for example, it is possible to remove bright objects or, for each spatial pixel, modify the spectral signature. The very promising results obtained on the mock-up of the programmable wide-field spectrograph reveal the efficiency of this new instrument concept for Earth Observation.

  3. RAISE (Rapid Acquisition Imaging Spectrograph Experiment): Results and Instrument Status

    NASA Astrophysics Data System (ADS)

    Laurent, Glenn T.; Hassler, Donald; DeForest, Craig; Ayres, Tom; Davis, Michael; DePontieu, Bart; Diller, Jed; Graham, Roy; Schule, Udo; Warren, Harry

    2015-04-01

    We present initial results from the successful November 2014 launch of the RAISE (Rapid Acquisition Imaging Spectrograph Experiment) sounding rocket program, including intensity maps, high-speed spectroheliograms and dopplergrams, as well as an update on instrument status. The RAISE sounding rocket payload is the fastest high-speed scanning-slit imaging spectrograph flown to date and is designed to observe the dynamics and heating of the solar chromosphere and corona on time scales as short as 100-200ms, with arcsecond spatial resolution and a velocity sensitivity of 1-2 km/s. The instrument is based on a class of UV/EUV imaging spectrometers that use only two reflections to provide quasi-stigmatic performance simultaneously over multiple wavelengths and spatial fields. The design uses an off-axis parabolic telescope mirror to form a real image of the sun on the spectrometer entrance aperture. A slit then selects a portion of the solar image, passing its light onto a near-normal incidence toroidal grating, which re-images the spectrally dispersed radiation onto two array detectors. Two full spectral passbands over the same one-dimensional spatial field are recorded simultaneously with no scanning of the detectors or grating. The two different spectral bands (1st-order 1205-1243Å and 1526-1564Å) are imaged onto two intensified Active Pixel Sensor (APS) detectors whose focal planes are individually adjusted for optimized performance. RAISE reads out the full field of both detectors at 5-10 Hz, allowing us to record over 1,500 complete spectral observations in a single 5-minute rocket flight, opening up a new domain of high time resolution spectral imaging and spectroscopy. RAISE is designed to study small-scale multithermal dynamics in active region (AR) loops, explore the strength, spectrum and location of high frequency waves in the solar atmosphere, and investigate the nature of transient brightenings in the chromospheric network.

  4. Prime Focus Spectrograph: A very wide-field, massively multiplexed, optical & near-infrared spectrograph for Subaru Telescope

    NASA Astrophysics Data System (ADS)

    Tamura, Naoyuki

    This short article is about Prime Focus Spectrograph (PFS), a very wide-field, massively-multiplexed, and optical & near-infrared (NIR) spectrograph as a next generation facility instrument on Subaru Telescope. More details and updates are available on the PFS official website (http://pfs.ipmu.jp), blog (http://pfs.ipmu.jp/blog/), and references therein. The project, instrument, & timeline PFS will position 2400 fibers to science targets or blank sky in the 1.3 degree field on the Subaru prime focus. These fibers will be quickly (~60sec) reconfigurable and feed the photons during exposures to the Spectrograph System (SpS). SpS consists of 4 modules each of which accommodate ~600 fibers and deliver spectral images ranging from 380nm to 1260nm simultaneously at one exposure via the 3 arms of blue, red, and NIR cameras. The instrument development has been undertaken by the international collaboration at the initiative of Kavli IPMU. The project is now going into the construction phase aiming at system integration and on-sky engineering observations in 2017-2018, and science operation in 2019. The survey design has also been under development envisioning a survey spanning ~300 nights over ~5 years in the framework of Subaru Strategic Program (SSP). The key science areas are: Cosmology, galaxy/AGN evolution, and Galactic Archaeology (GA) (Takada et al. 2014). The cosmology program will be to constrain the nature of dark energy via a survey of emission line galaxies over a comoving volume of 10 Gpc3 at z=0.8-2.4. In the galaxy/AGN program, the wide wavelength coverage of PFS as well as the large field of view will be exploited to characterize the galaxy populations and its clustering properties over a wide redshift range. A survey of color-selected galaxies/AGN at z = 1-2 will be conducted over 20 square degrees yielding a fair sample of galaxies with stellar masses down to ~1010 M ⊙. In the GA program, radial velocities and chemical abundances of stars in the Milky

  5. Prime Focus Spectrograph: A very wide-field, massively multiplexed, optical & near-infrared spectrograph for Subaru Telescope

    NASA Astrophysics Data System (ADS)

    TAMURA, NAOYUKI

    2015-08-01

    PFS (Prime Focus Spectrograph), a next generation facility instrument on Subaru, is a very wide-field, massively-multiplexed, and optical & near-infrared spectrograph. Exploiting the Subaru prime focus, 2400 reconfigurable fibers will be distributed in the 1.3 degree field. The spectrograph will have 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm at one exposure. The development of this instrument has been undertaken by the international collaboration at the initiative of Kavli IPMU. The project is now going into the construction phase aiming at system integration and on-sky commissioning in 2017-2018, and science operation in 2019. In parallel, the survey design has also been developed envisioning a Subaru Strategic Program (SSP) that spans roughly speaking 300 nights over 5 years. The major science areas are three-folds: Cosmology, galaxy/AGN evolution, and Galactic archaeology (GA). The cosmology program will be to constrain the nature of dark energy via a survey of emission line galaxies over a comoving volume of ~10 Gpc^3 in the redshift range of 0.8 < z < 2.4. In the GA program, radial velocities and chemical abundances of stars in the Milky Way, dwarf spheroidal galaxies, and M31 will be used to understand the past assembly histories of those galaxies and the structures of their dark matter halos. Spectra will be taken for ~1 million stars as faint as V = 22 therefore out to large distances from the Sun. For the extragalactic program, our simulations suggest the wide wavelength coverage of PFS will be particularly powerful in probing the galaxy populations and its clustering properties over a wide redshift range. We will conduct a survey of color-selected 1 < z < 2 galaxies and AGN over 20 square degrees down to J = 23.4, yielding a fair sample of galaxies with stellar masses above ˜10^10 solar masses. Further, PFS will also provide unique spectroscopic opportunities even in the era of Euclid, LSST

  6. Integration and test activities for the SUMIRE prime focus spectrograph at LAM

    NASA Astrophysics Data System (ADS)

    Madec, F.; Jaquet, Marc; Pascal, Sandrine; Bozier, A.; Le Mignant, David; Vives, S.; Ferrand, D.; Pegot-Ogier, T.; Arthaud, G.; Golebiowski, M.; Sugai, H.; Tamura, N.; Gunn, J.; Smee, S.; Oliveira, L.

    2014-07-01

    The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project for Subaru telescope consists in four identical spectrographs feed by 600 fibers each. Each spectrograph is composed by an optical entrance unit that creates a collimated beam and distributes the light to three channels, two visible and one near infrared. We present here the integration process of the first spectrograph channel. The verification requirements, the specific integration requirements and the product tree are the main drivers from the top plan for the Assembly Integration and Test (AIT) development process. We then present the AIT flow-down, the details for the AIT processes as well as opto-mechanical alignment procedures and tests setup. In parallel, we are developing and validating dedicated tools to secure and facilitate the AIT activities, as we have to assemble eight visible cameras, integrate and align four fiber slits, integrate and align the components of four spectrographs.

  7. Compact microchannel system

    DOEpatents

    Griffiths, Stewart

    2003-09-30

    The present invention provides compact geometries for the layout of microchannel columns through the use of turns and straight channel segments. These compact geometries permit the use of long separation or reaction columns on a small microchannel substrate or, equivalently, permit columns of a fixed length to occupy a smaller substrate area. The new geometries are based in part on mathematical analyses that provide the minimum turn radius for which column performance in not degraded. In particular, we find that straight channel segments of sufficient length reduce the required minimum turn radius, enabling compact channel layout when turns and straight segments are combined. The compact geometries are obtained by using turns and straight segments in overlapped or nested arrangements to form pleated or coiled columns.

  8. Compact turbidity meter

    NASA Technical Reports Server (NTRS)

    Hirschberg, J. G.

    1979-01-01

    Proposed monitor that detects back-reflected infrared radiation makes in situ turbidity measurements of lakes, streams, and other bodies of water. Monitor is compact, works well in daylight as at night, and is easily operated in rough seas.

  9. Progress with the Prime Focus Spectrograph for the Subaru Telescope: a massively multiplexed optical and near-infrared fiber spectrograph

    NASA Astrophysics Data System (ADS)

    Sugai, Hajime; Tamura, Naoyuki; Karoji, Hiroshi; Shimono, Atsushi; Takato, Naruhisa; Kimura, Masahiko; Ohyama, Youichi; Ueda, Akitoshi; Aghazarian, Hrand; de Arruda, Marcio V.; Barkhouser, Robert H.; Bennett, Charles L.; Bickerton, Steve; Bozier, Alexandre; Braun, David F.; Bui, Khanh; Capocasale, Christopher M.; Carr, Michael A.; Castilho, Bruno; Chang, Yin-Chang; Chen, Hsin-Yo; Chou, Richard C. Y.; Dawson, Olivia R.; Dekany, Richard G.; Ek, Eric M.; Ellis, Richard S.; English, Robin J.; Ferrand, Didier; Ferreira, Décio; Fisher, Charles D.; Golebiowski, Mirek; Gunn, James E.; Hart, Murdock; Heckman, Timothy M.; Ho, Paul T. P.; Hope, Stephen; Hovland, Larry E.; Hsu, Shu-Fu; Hu, Yen-Sang; Huang, Pin Jie; Jaquet, Marc; Karr, Jennifer E.; Kempenaar, Jason G.; King, Matthew E.; Le Fèvre, Olivier; Le Mignant, David; Ling, Hung-Hsu; Loomis, Craig; Lupton, Robert H.; Madec, Fabrice; Mao, Peter; Marrara, Lucas S.; Ménard, Brice; Morantz, Chaz; Murayama, Hitoshi; Murray, Graham J.; de Oliveira, Antonio Cesar; de Oliveira, Claudia M.; de Oliveira, Ligia S.; Orndorff, Joe D.; de Paiva Vilaça, Rodrigo; Partos, Eamon J.; Pascal, Sandrine; Pegot-Ogier, Thomas; Reiley, Daniel J.; Riddle, Reed; Santos, Leandro; dos Santos, Jesulino B.; Schwochert, Mark A.; Seiffert, Michael D.; Smee, Stephen A.; Smith, Roger M.; Steinkraus, Ronald E.; Sodré, Laerte; Spergel, David N.; Surace, Christian; Tresse, Laurence; Vidal, Clément; Vives, Sebastien; Wang, Shiang-Yu; Wen, Chih-Yi; Wu, Amy C.; Wyse, Rosie; Yan, Chi-Hung

    2014-07-01

    The Prime Focus Spectrograph (PFS) is an optical/near-infrared multi-fiber spectrograph with 2394 science fibers, which are distributed in 1.3 degree diameter field of view at Subaru 8.2-meter telescope. The simultaneous wide wavelength coverage from 0.38 μm to 1.26 μm, with the resolving power of 3000, strengthens its ability to target three main survey programs: cosmology, Galactic archaeology, and galaxy/AGN evolution. A medium resolution mode with resolving power of 5000 for 0.71 μm to 0.89 μm also will be available by simply exchanging dispersers. PFS takes the role for the spectroscopic part of the Subaru Measurement of Images and Redshifts (SuMIRe) project, while Hyper Suprime-Cam (HSC) works on the imaging part. HSC's excellent image qualities have proven the high quality of the Wide Field Corrector (WFC), which PFS shares with HSC. The PFS collaboration has succeeded in the project Preliminary Design Review and is now in a phase of subsystem Critical Design Reviews and construction. To transform the telescope plus WFC focal ratio, a 3-mm thick broad-band coated microlens is glued to each fiber tip. The microlenses are molded glass, providing uniform lens dimensions and a variety of refractive-index selection. After successful production of mechanical and optical samples, mass production is now complete. Following careful investigations including Focal Ratio Degradation (FRD) measurements, a higher transmission fiber is selected for the longest part of cable system, while one with a better FRD performance is selected for the fiber-positioner and fiber-slit components, given the more frequent fiber movements and tightly curved structure. Each Fiber positioner consists of two stages of piezo-electric rotary motors. Its engineering model has been produced and tested. After evaluating the statistics of positioning accuracies, collision avoidance software, and interferences (if any) within/between electronics boards, mass production will commence. Fiber

  10. DYNAMICS IN SUNSPOT UMBRA AS SEEN IN NEW SOLAR TELESCOPE AND INTERFACE REGION IMAGING SPECTROGRAPH DATA

    SciTech Connect

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

    2015-01-10

    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 Å and Si IV 1393.76 Å 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 Hα 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.

  11. Multi-object spectroscopy on the Hobby-Eberly Telescope low-resolution spectrograph

    NASA Astrophysics Data System (ADS)

    Wolf, Marsha J.; Hill, Gary J.; Mitsch, Wolfgang; Hessman, Frederic V.; Altmann, Werner; Thompson, Keith L.

    2000-08-01

    The low resolution spectrograph (LRS) is the first facility instrument on the 9.2m Hobby-Eberly Telescope (HET). The LRS has three operational modes: imaging, long-slit spectroscopy and multi-object spectroscopy (MOS). We present the design and early operations performance of the LRS MOS unit, which provides 13 slitless, each 1.3 arcsec by 15 arcsec, on 19.6 arcsec centers, within the 4 arcmin field of view of the HET. This type of remotely configurable unit was chosen over the more conventional slit masks due to the queue scheduling of the HET, and the instrument's remote location at the prime focus of the telescope. A restricted envelope around the HET focus at the LRS port forced a very compact design. The MOS unit has miniature mechanisms base don custom cross- roller stages and 0.25 mm pitch lead-screws. Geared stepper motors with 10 mm diameters drive the 13 axes at 0.8 micron per step. The precision of the mechanism is far greater than required by the HET plate scale of 205 microns per arcsec, but result in a robust unit. The slitlets were fabricated at the University of Texas by shadow-masking the slit area with a wire and vacuum depositing aluminum onto the silica substrates. Both sides are then coated with MgF2 which serves as an antireflection coating and a protective layer. Web-based software is available for optimizing the orientation of the MOS unit and the placement of slitlets on objects in the field. These setup scan be down loaded to the unit for configuration outside of the beam while the HET is slewing to its next target in the queue, or while the LRS is used in imaging mode for setup on faint objects. The preliminary results presented here are from one commissioning run with the MOS, where the unit appears to be meeting performance specifications.

  12. Optical Spectrum of the Compact Planetary Nebula IC 5117

    NASA Technical Reports Server (NTRS)

    Hyung, Siek; Aller, Lawrence H.; Feibelman, Walter A.; Lee, Seong-Jae; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    High resolution spectroscopic data of the very compact planetary nebula IC 5117 are obtained in the optical wavelengths, 3700A - 10050A, with the Hamilton Echelle Spectrograph at Lick Observatory, and which have been analyzed along with the International Ultraviolet Explorer (IUE) UV archive data. Although a diagnostic diagram shows significant density and temperature fluctuations, our analysis indicates that the nebular gas may be represented by a homogeneous shell of extremely high density gas, N(sub epsilon) approx. 90 000 /cu cm. The average electron temperatures, e.g. indicated by the [OIII] diagnostics, are around 12 000 K. We construct a photoionization model to represent most of the observed line intensities, and the physical condition of this compact nebulosity. Based on the semi-empirical ionization correction approach, and model indications, we derived the elemental abundances: He, C, N, O, Ne, and Ar appear to be normal or marginally depleted compared to the average planetary nebula, while the remaining elements, S, Cl, and K appear to be enhanced. IC 5117 is perhaps a very young compact planetary nebula, slightly more evolved than the other well-known compact planetary nebula IC 4997. The central stellar temperature is likely to be around 120 000 K, evolved from a C-rich AGB progenitor.

  13. PRAXIS: a low background NIR spectrograph for fibre Bragg grating OH suppression

    NASA Astrophysics Data System (ADS)

    Horton, Anthony; Ellis, Simon; Lawrence, Jon; Bland-Hawthorn, Joss

    2012-09-01

    Fibre Bragg grating (FBG) OH suppression is capable of greatly reducing the bright sky background seen by near infrared spectrographs. By filtering out the airglow emission lines at high resolution before the light enters the spectrograph this technique prevents scattering from the emission lines into interline regions, thereby reducing the background at all wavelengths. In order to take full advantage of this sky background reduction the spectrograph must have very low instrumental backgrounds so that it remains sky noise limited. Both simulations and real world experience with the prototype GNOSIS system show that existing spectrographs, designed for higher sky background levels, will be unable to fully exploit the sky background reduction. We therefore propose PRAXIS, a spectrograph optimised specifically for this purpose. The PRAXIS concept is a fibre fed, fully cryogenic, fixed format spectrograph for the J and H-bands. Dark current will be minimised by using the best of the latest generation of NIR detectors while thermal backgrounds will be reduced by the use of a cryogenic fibre slit. Optimised spectral formats and the use of high throughput volume phase holographic gratings will further enhance sensitivity. Our proposal is for a modular system, incorporating exchangeable fore-optics units, integral field units and OH suppression units, to allow PRAXIS to operate as a visitor instrument on any large telescope and enable new developments in FBG OH suppression to be incorporated as they become available. As a high performance fibre fed spectrograph PRAXIS could also serve as a testbed for other astrophotonic technologies.

  14. Design and realization of the real-time spectrograph controller for LAMOST based on FPGA

    NASA Astrophysics Data System (ADS)

    Wang, Jianing; Wu, Liyan; Zeng, Yizhong; Dai, Songxin; Hu, Zhongwen; Zhu, Yongtian; Wang, Lei; Wu, Zhen; Chen, Yi

    2008-08-01

    A large Schmitt reflector telescope, Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST), is being built in China, which has effective aperture of 4 meters and can observe the spectra of as many as 4000 objects simultaneously. To fit such a large amount of observational objects, the dispersion part is composed of a set of 16 multipurpose fiber-fed double-beam Schmidt spectrographs, of which each has about ten of moveable components realtimely accommodated and manipulated by a controller. An industrial Ethernet network connects those 16 spectrograph controllers. The light from stars is fed to the entrance slits of the spectrographs with optical fibers. In this paper, we mainly introduce the design and realization of our real-time controller for the spectrograph, our design using the technique of System On Programmable Chip (SOPC) based on Field Programmable Gate Array (FPGA) and then realizing the control of the spectrographs through NIOSII Soft Core Embedded Processor. We seal the stepper motor controller as intellectual property (IP) cores and reuse it, greatly simplifying the design process and then shortening the development time. Under the embedded operating system μC/OS-II, a multi-tasks control program has been well written to realize the real-time control of the moveable parts of the spectrographs. At present, a number of such controllers have been applied in the spectrograph of LAMOST.

  15. Active compensation of flexure on the High-Resolution Optical Spectrograph for Gemini

    NASA Astrophysics Data System (ADS)

    D'Arrigo, P.; Diego, Francisco; Walker, David D.

    1997-03-01

    Gravity-induced flexure has been a long-standing challenge in Cassegrain spectrographs at 4-meter class telescopes; it is the more so at the scale of 8-meter telescopes. This is of particular concern for the Gemini high resolution optical spectrograph, which will be Cassegrain-mounted for its routine mode of operation. In this paper we address the general flexure problem, and how to solve it with the use of active optics. We also present the results of an experimental active flexure compensation system for the ISIS (intermediate- dispersion spectroscopic and imaging system) spectrograph on the 4.2 m William Herschel Telescope (WHT). This instrument, called ISAAC (ISIS spectrograph automatic active collimator), is based on the concept of active correction, where spectrum drifts, due to the spectrograph flexing under the effect of gravity, are compensated by the movement of an active optical element (in this case a fine steering tip-tilt collimator mirror). The experiment showed that active compensation can reduce flexure down to less than 3 micrometer over four hours of telescope motions, dramatically improving the spectrograph performance. The results of the experiment are used to discuss a flexure compensation system for the high resolution optical spectrograph (HROS) for the 8 m Gemini telescope.

  16. Slit Function Measurement of An Imaging Spectrograph Using Fourier Transform Techniques

    NASA Technical Reports Server (NTRS)

    Park, Hongwoo; Swimyard, Bruce; Jakobsen, Peter; Moseley, Harvey; Greenhouse, Matthew

    2004-01-01

    Knowledge of a spectrograph slit function is necessary to interpret the unresolved lines in an observed spectrum. A theoretical slit function can be calculated from the sizes of the entrance slit, the detector aperture when it functions as an exit slit, the dispersion characteristic of the disperser, and the point spread function of the spectrograph. A measured slit function is preferred to the theoretical one for the correct interpretation of the spectral data. In a scanning spectrometer with a single exit slit, the slit function is easily measured. In a fixed grating/or disperser spectrograph, illuminating the entrance slit with a near monochromatic light from a pre-monochrmator or a tunable laser and varying the wavelength of the incident light can measure the slit function. Even though the latter technique had been used successfully for the slit function measurements, it had been very laborious and it would be prohibitive to an imaging spectrograph or a multi-object spectrograph that has a large field of view. We explore an alternative technique that is manageable for the measurements. In the proposed technique, the imaging spectrograph is used as a detector of a Fourier transform spectrometer. This method can be applied not only to an IR spectrograph but also has a potential to a visible/UV spectrograph including a wedge filter spectrograph. This technique will require a blackbody source of known temperature and a bolometer to characterize the interferometer part of the Fourier Transform spectrometer. This pa?er will describe the alternative slit function measurement technique using a Fourier transform spectrometer.

  17. Physically detached 'compact groups'

    NASA Technical Reports Server (NTRS)

    Hernquist, Lars; Katz, Neal; Weinberg, David H.

    1995-01-01

    A small fraction of galaxies appear to reside in dense compact groups, whose inferred crossing times are much shorter than a Hubble time. These short crossing times have led to considerable disagreement among researchers attempting to deduce the dynamical state of these systems. In this paper, we suggest that many of the observed groups are not physically bound but are chance projections of galaxies well separated along the line of sight. Unlike earlier similar proposals, ours does not require that the galaxies in the compact group be members of a more diffuse, but physically bound entity. The probability of physically separated galaxies projecting into an apparent compact group is nonnegligible if most galaxies are distributed in thin filaments. We illustrate this general point with a specific example: a simulation of a cold dark matter universe, in which hydrodynamic effects are included to identify galaxies. The simulated galaxy distribution is filamentary and end-on views of these filaments produce apparent galaxy associations that have sizes and velocity dispersions similar to those of observed compact groups. The frequency of such projections is sufficient, in principle, to explain the observed space density of groups in the Hickson catalog. We discuss the implications of our proposal for the formation and evolution of groups and elliptical galaxies. The proposal can be tested by using redshift-independent distance estimators to measure the line-of-sight spatial extent of nearby compact groups.

  18. Mathematical model of orbital and ground-based cross-dispersion spectrographs

    NASA Astrophysics Data System (ADS)

    Yushkin, M. V.; Fatkhullin, T. A.; Panchuk, V. E.

    2016-07-01

    We present the technique and algorithm of numerical modeling of high-resolution spectroscopic equipment. The software is implemented in C++ using nVidia CUDA technology. We report the results of currently developedmodeling of new-generation echelle spectrographs. To validate the algorithms used to construct the mathematical model, we present the results of modeling of NES spectrograph of the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. A comparison of simulated and real images of the spectra acquired with NES spectrograph demonstrates good agreement between the model constructed and experimental data.

  19. EMIR: a Near-Infrared Multiobject Spectrograph for the GTC

    NASA Astrophysics Data System (ADS)

    Garzón, F.; Fuentes, J.; Manescau, A.; Díaz, J. J.; Patrón, J.; Pelló, R.; López, J. C.; Pérez, J.; Fragoso, A. B.; Gago, F.; Beigbeder, F.; Sanchez, V.; Correa, S.; Villegas, A.

    In this contribution, we review the overall features of EMIR, the NIR multiobject spectrograph of the GTC. EMIR is at present in the middle of its PD phase and will be one of the first common user instruments for the GTC, the 10 meter telescope under construction by GRANTECAN at the Roque de los Muchachos Observatory (Canary Islands, Spain). EMIR is being built by a Consortium of Spanish, French, and British institutes led by the IAC. EMIR is designed to realize one of the central goals of 10 m class telescopes, that of allowing observers to obtain spectra for large numbers of faint sources in a time-efficient manner. EMIR is primarily designed to be operated as a MOS in the K band but offers a wide range of observing modes, including imaging and spectroscopy, both long slit and multiobject, in the wavelength range 0.9 to 2.5 μ m. The present status of development of EMIR, its expected performance, and the project schedule are described and discussed. This project is funded by GRANTECAN and the Plan Nacional de Astronomía y Astrofísica (National Plan for Astronomy and Astrophysics, Spain).

  20. EMIR: the GTC NIR multiobject imager-spectrograph

    NASA Astrophysics Data System (ADS)

    Garzon, Francisco; Barrera, S.; Correa, Santiago; Diaz-Garcia, Jose J.; Fragoso-Lopez, Ana B.; Fuentes, F. Javier; Gago, Fernando; Lopez-Ruiz, Jose-Carlos; Manescau, Antonio; Patron, Jesus; Perez-Espinos, Jaime; Sanchez de la Rosa, Vicente; Villegas, Alejandro; Redondo, Pablo

    2003-03-01

    In this contribution we review the overall features of EMIR, the NIR multiobject spectrograph of the GTC. EMIR is at present in the middle of the PD phase and will be one of the first common user instruments for the GTC, the 10 meter telescope under construction by GRANTECAN at the Roque de los Muchachos Observatory (Canary Islands, Spain). EMIR is being built by a Consortium of Spanish, French and British institutes led by the IAC. EMIR is designed to realize one of the central goals of 10m class telescopes, allowing observers to obtain spectra for large numbers of faint sources in an time-efficient manner. EMIR is primarily designed to be operated as a MOS in the K band, but offers a wide range of observing modes, including imaging and spectroscopy, both long slit and multiobject, in the wavelength range 0.9 to 2.5 μm. The present status of development, expected performances and schedule are described and discussed. This project is funded by GRANTECAN and the Plan Nacional de Astronomía y Astrofísica (National Plan for Astronomy and Astrophysics, Spain).

  1. Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrograph

    NASA Astrophysics Data System (ADS)

    Wilson, John C.; Hearty, F.; Skrutskie, M. F.; Majewski, S. R.; Schiavon, R.; Eisenstein, D.; Gunn, J.; Gillespie, B.; Weinberg, D.; Blank, B.; Henderson, C.; Smee, S.; Barkhouser, R.; Harding, A.; Hope, S.; Fitzgerald, G.; Stolberg, T.; Arns, J.; Nelson, M.; Brunner, S.; Burton, A.; Walker, E.; Lam, C.; Maseman, P.; Barr, J.; Leger, F.; Carey, L.; MacDonald, N.; Ebelke, G.; Beland, S.; Horne, T.; Young, E.; Rieke, G.; Rieke, M.; O'Brien, T.; Crane, J.; Carr, M.; Harrison, C.; Stoll, R.; Vernieri, M.; Holtzman, J.; Nidever, D.; Shetrone, M.; Allende-Prieto, C.; Johnson, J.; Frinchaboy, P.; Zasowski, G.; Garcia Perez, A.; Bizyaev, D.; Zhao, B.

    2012-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) will observe approximately 100,000 giant stars in the Milky Way with a dedicated fiber-fed (300 fibers from the Sloan 2.5-m telescope) near-infrared (1.5-1.7 micron) high resolution (R 22,500) spectrograph as part of the Sloan Digital Sky Survey III (SDSS-III). By observing in the near-infrared, APOGEE can uniformly sample all Milky Way stellar populations (bulge, thin/thick disks and halo) in the same survey to dramatically improve our understanding of the kinematical and chemical enrichment history of our galaxy. The instrument design includes several innovations: a novel fiber gang connector that allows simultaneous optical connection of 300 fibers from the instrument into swappable plug plate cartridges, the first deployed mosaic volume phase holographic (VPH) grating, and a very large ( 0.4-m) aperture six-element refractive camera incorporating crystalline silicon elements to image 300 spectra onto three HAWAII-IIRG detectors simultaneously.

  2. Performance of the Space Telescope Imaging Spectrograph after SM4

    NASA Technical Reports Server (NTRS)

    Proffitt, Charles R.; Alosi, A.; Bohlin, R. C.; Bostroen, K. A.; Cox, C. R.; Diaz, R. I.; Dixon, W. V.; Goudfrooij, P.; Hodge, P.; Kaiser, M. E.; Lallo, M. D.; Lennon, D.; Niemi, S.; Pascucci, I.; Smith, E.; Wolfe, M. A.; York, B.; Zheng. W.; Gull, T. R.; Lindler, D. J.; Woodgate, B. E.

    2010-01-01

    On May 17, 2009, during the fourth EVA of SM4, astronauts Michael Good and Mike Massimino replaced the failed LVPS-2 circuit board on the Space Telescope Imaging Spectrograph (STIS), restoring this HST instrument to operation after a nearly 6 year hiatus. STIS after this 2009 repair operates in much the same way as it did during the 2001-2004 period of operations with the Side-2 electronics. Internal and external alignments of the instrument are similar to what they had been in 2004, and most changes in performance are modest. The STIS CCD detector continued to experience radiation damage during the hiatus in operations, leading to decreased charge transfer efficiency (CTE) and an increased number of hot pixels. The sensitivities for most modes are surprisingly close to what was expected from simple extrapolation of the 2003-2004 trends, although the echelle modes show somewhat more complex behavior. The biggest surprise was that the dark count rate for the NUV MAMA detector after SM4 has been much larger than had been expected; it is currently about 2.5 times bigger than it was in 2004 and is only slowly decreasing. We discuss how these changes will affect science with STIS now and in the future.

  3. Gemini high-resolution optical spectrograph conceptual design

    NASA Astrophysics Data System (ADS)

    Szeto, Kei; McConnachie, Alan; Anthony, André; Bohlender, David; Crampton, David; Desaulniers, Pierre; Dunn, Jennifer; Hardy, Tim; Hill, Alexis; Monin, Dmitry; Pazder, John; Schwab, Christian; Spano, Paola; Starkenburg, Else; Thibault, Simon; Walker, Gordon; Venn, Kim; Zhang, Hu

    2012-09-01

    A multiplexed moderate resolution (R = 34,000) and a single object high resolution (R = 90,000) spectroscopic facility for the entire 340 - 950nm wavelength region has been designed for Gemini. The result is a high throughput, versatile instrument that will enable precision spectroscopy for decades to come. The extended wavelength coverage for these relatively high spectral resolutions is achieved by use of an Echelle grating with VPH cross-dispersers and for the R = 90,000 mode utilization of an image slicer. The design incorporates a fast, efficient, reliable system for acquiring targets over the7 arcmin field of Gemini. This paper outlines the science case development and requirements flow-down process that leads to the configuration of the HIA instrument and describes the overall GHOS conceptual design. In addition, this paper discusses design trades examined during the conceptual design study instrument group of the Herzberg Institute of Astrophysics has been commissioned by the Gemini Observatory as one of the three competing organizations to conduct a conceptual design study for a new Gemini High-Resolution Optical Spectrograph (GHOS). This paper outlines the science case development and requirements flow-down process that leads to the configuration of the HIA instrument and describes the overall GHOS conceptual design. In addition, this paper discusses design trades examined during the conceptual design study.

  4. Goddard High Resolution Spectrograph SV/GTO Project

    NASA Technical Reports Server (NTRS)

    Ebbets, Dennis

    1999-01-01

    Contract number NAS5-30433, known at Ball Aerospace as the GHRS SV/GTO project, supported our participation in the post-launch activities of the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope. The period of performance was December 1988 through December 1998. The contract supported the involvement of Dr Dennis Ebbets in the work of the GHRS Investigation Definition Team, and several of the Ball people in the documentation and publication of results. Three main categories of tasks were covered by this contract; in-orbit calibration of the GHRS, guaranteed time observations, and education and public outreach. The nature and accomplishments of these tasks are described in the report. This summary makes many references to publications in the scientific and technical literature. Appendix A is extracted from a complete bibliography, and lists those papers that are directly related to work performed under this GHRS contract. The tasks related to the in-orbit calibration of the GHRS were by far the largest responsibility during the first six years of the project. During this period Dr. Ebbets was responsible for the definition of calibration requirements, design of experiments, preparation of observing proposals, tracking their implementation and execution, and coordinating the analysis and publication of the results. Prior to the launch of HST in 1990 the observing proposals were developed in cooperation with the scientists on the GHRS DDT, engineers at Ball Aerospace, the operations staff at the STScI, and project coordinators at GSFC.

  5. Gemini Multi-Object Spectrograph Upgrades: Hamamatsu CCDs and AO

    NASA Astrophysics Data System (ADS)

    Roth, Katherine; Gimeno, G.; Murowinski, R.; Kleinman, S.; Trujillo, C. A.; Lai, O.

    2014-01-01

    The Gemini Multi-Object Spectrographs (GMOS) at both Gemini North and South have provided crucial access to longslit, MOS and IFU moderate resolution optical spectroscopy for the Gemini international partnership for over a decade. The interim installment of e2v deep depletion CCDs at GMOS-N in November 2011, providing enhanced red sensitivity, was the first major upgrade for either GMOS since the implementation of the Nod&Shuffle mode in 2002. We present plans to replace the original EEV detectors in GMOS-S with new Hamamatsu CCDs, extending wavelength coverage out beyond 1.03 microns. GMOS-N upgrade to Hamamatsu CCDs will follow the successful deployment on GMOS-S. With the extension of GMOS sensitivity further to long wavelengths it becomes even more attractive to extend the number of observing modes to include adaptive optics imaging and spectroscopy. As has already been demonstrated with GEMS/GMOS-S imaging, adaptive optics in the 0.8-1 micron wavelength regime on Gemini can effectively transform IQ70 conditions to IQ20 and more than double the spatial resolution over the natural seeing. We present plans to move forward with plans to enable GMOS + adaptive optics as a regular user mode at both sites.

  6. Interface Region Imaging Spectrograph (IRIS) entrance aperture design

    NASA Astrophysics Data System (ADS)

    Cheimets, P.; Park, S.; Bergner, H.; Chou, C.; Gates, R.; Honsa, M.; Podgorski, W.; Yanari, C.

    2014-07-01

    The Interface Region Imaging Spectrograph (IRIS) is a complementary follow-on to Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO-AIA) and funded as a member of the NASA SMEX program. This paper presents the thermal design of the IRIS telescope front end, with a focus on the IRIS door and entrance aperture assembly. The challenge of the IRIS entrance aperture, including the door design, was to manage the solar flux, both before and after the door was opened. This is especially a problem with instruments that are permanently pointed directly at the sun. Though there is an array of effective flux-rejecting coatings, they are expensive, hard to apply, harder to measure, delicate, prone to unpredictable performance decay with exposure, and very often a source of contamination. This paper presents a thermal control and protection method based on robust, inexpensive coatings and materials, combined to produce high thermal and structural isolation. The end result is a first line of thermal protection whose performance is easy to predict and well isolated from the instrument it is protecting.

  7. Conceptual design of the MOBIE imaging spectrograph for TMT

    NASA Astrophysics Data System (ADS)

    Bigelow, Bruce C.; Radovan, Matthew V.; Bernstein, Rebecca A.; Onaka, Peter M.; Yamada, Hubert; Isani, Sidik; Miyazaki, Satoshi; Ozaki, Shinobu

    2014-08-01

    The Multi-Object Broadband Imaging Echellette (MOBIE) is the seeing-limited, visible-wavelength imaging multiobject spectrograph (MOS) planned for first-light use on the Thirty Meter Telescope (TMT). The MOBIE project to date has been a collaboration lead by UC Observatories (CA), and including the UH Institute for Astronomy (HI), and the NAOJ (Tokyo, Japan). The current MOBIE optical design provides two color channels, spanning the 310-550nm and 550-1000nm passbands, and a combination of reflection gratings, prisms, and mirrors to enable direct imaging and three spectroscopic modes with resolutions (λ/triangle λ) of roughly 1000, 3000, and 8000 in both color channels, across a field of view that ranges from roughly 8x3 arcmin to 3x3 arcmin, depending on resolution mode. The conceptual design phase for the MOBIE instrument has been underway since 2008 and is expected to end in 2015. We report here on developments since 2010, including assembly of the current project team, instrument and camera optical designs, instrument control systems, atmospheric dispersion corrector, slit-mask exchange systems, collimator, dichroic and fold optics, dispersing and cross-dispersing optics, refracting cameras, shutters, filter exchange systems, science detector systems, and instrument structures.

  8. Performance of the Space Telescope Imaging Spectrograph after

    NASA Astrophysics Data System (ADS)

    Proffitt, Charles R.; Aloisi, A.; Bohlin, C.; Bostroem, K. A.; Cox, C. R.; Diaz, R. I.; Dixon, W. V.; Goudfrooij, P.; Hodge, P.; Kaiser, M. E. Lallo, M. D.; Lennon, D.; Niemi, S.; Osten, R. A.; Pascucci, I.; Smith, E.; Wolfe, M. A.; York, B.; Zheng, W.; Gull, T. R.; Lindler, D. J.; Woodgate, B. E.

    2010-07-01

    On May 17, 2009, during the fourth EVA of SM4, astronauts Michael Good and Mike Massimino replaced the failed LVPS-2 circuit board on the Space Telescope Imaging Spectrograph (STIS), restoring this HST instrument to operation after a nearly 6 year hiatus. STIS after this 2009 repair operates in much the same way as it did during the 2001-2004 period of operations with the Side-2 electronics. Internal and external alignments of the instrument are similar to what they had been in 2004, and most changes in performance are modest. The STIS CCD detector continued to experience radiation damage during the hiatus in operations, leading to decreased charge transfer efficiency (CTE) and an increased number of hot pixels. The sensitivities for most modes are surprisingly close to what was expected from simple extrapolation of the 2003-2004 trends, although the echelle modes show somewhat more complex behavior. The biggest surprise was that the dark count rate for the NUV MAMA detector after SM4 has been much larger than had been expected; it is currently about 2.5 times bigger than it was in 2004 and is only slowly decreasing. We discuss how these changes will affect science with STIS now and in the future.

  9. Mid-infrared camera/spectrograph for OAN/SPM

    NASA Astrophysics Data System (ADS)

    Sohn, Erika; Ruiz, Elfego; Cruz-Gonzales, Irene; Salas, Luis

    1998-08-01

    The design concepts of a mid-IR camera/spectrograph, based on a HUGHES/SBRC 320 by 240 Si:As IBC sensor chip assembly (SCA), are presented, The system will operate in the 2 to 28 micrometers wavelength interval and will be optimized in the 10 micrometers regime. This SCA is divided into 32 regions, each with an independent output. The outputs, after being amplified and sampled, are multiplexed into 8 high speed 16 bit A/D converters. The initial configuration allows readout rates of up to 60 frame/s. A higher speed frame readout configuration is foreseen. A 32 bit deep memory and a high speed ALU, synchronized to the detector, will co- add/subtract the frames, making a real time visualization during the integration process possible. The detector, reflective optics, low resolution gratings, several cold stops, baffles, up to 12 filters and a CVF will be allocated in a 10 inch diameter working surface LN(subscript 2)/LHe dewar. The system will be linked to a workstation, providing a user friendly environment. The system is planned to operate at the Observatorio Astronomic Nacional in San Pedro Martir, B.C., Mexico.

  10. IONIZED OUTFLOWS FROM COMPACT STEEP SPECTRUM SOURCES

    SciTech Connect

    Shih, Hsin-Yi; Stockton, Alan; Kewley, Lisa E-mail: stockton@ifa.hawaii.edu

    2013-08-01

    Massive outflows are known to exist, in the form of extended emission-line regions (EELRs), around about one-third of powerful FR II radio sources. We investigate the origin of these EELRs by studying the emission-line regions around compact-steep-spectrum (CSS) radio galaxies that are younger (10{sup 3}-10{sup 5} yr old) versions of the FR II radio galaxies. We have searched for and analyzed the emission-line regions around 11 CSS sources by taking integral field spectra using Gemini Multi-Object Spectrograph on Gemini North. We fit the [O III] {lambda}5007 line and present the velocity maps for each detected emission-line region. We find, in most cases, that the emission-line regions have multi-component velocity structures with different velocity dispersions and/or flux distributions for each component. The velocity gradients of the emission-line gas are mostly well aligned with the radio axis, suggesting a direct causal link between the outflowing gas and the radio jets. The complex velocity structure may be a result of different driving mechanisms related to the onset of the radio jets. We also present the results from the line-ratio diagnostics we used to analyze the ionization mechanism of the extended gas, which supports the scenario where the emission-line regions are ionized by a combination of active galactic nucleus radiation and shock excitation.

  11. A Spectrographic Investigation of Consonant-Vowel Transitions in the Speech of Deaf Adults

    ERIC Educational Resources Information Center

    Rothman, Howard B.

    1976-01-01

    A spectrographic investigation was carried out on the speech of normal hearing and deaf speakers; the research attempted to answer questions concerning formant transitions, coarticulation and neutralization of vowels in the speech of the deaf adults. (Author/RM)

  12. Radiometric performance results of the Juno ultraviolet spectrograph (Juno-UVS)

    NASA Astrophysics Data System (ADS)

    Davis, Michael W.; Gladstone, G. Randall; Greathouse, Thomas K.; Slater, David C.; Versteeg, Maarten H.; Persson, Kristian B.; Winters, Gregory S.; Persyn, Steven C.; Eterno, John S.

    2011-09-01

    We describe the radiometric performance and ground calibration results of the Juno mission's Ultraviolet Spectrograph (Juno-UVS) flight model. Juno-UVS is a modest power (9.0 W) ultraviolet spectrograph based on the Alice instruments now in flight aboard the European Space Agency's Rosetta spacecraft, NASA's New Horizons spacecraft, and the LAMP instrument aboard NASA's Lunar Reconnaissance Orbiter. Its primary job will be to characterize Jupiter's UV auroral emissions and relate them to in situ particle measurements.

  13. Compact, Integrated Photoelectron Linacs

    NASA Astrophysics Data System (ADS)

    Yu, David

    2000-12-01

    The innovative compact high energy iniector which has been developed by DULY Research Inc., will have wide scientific industrial and medical applications. The new photoelectron injector integrates the photocathode directly into a multicell linear accelerator with no drift space between the injector and the linac. By focusing the beam with solenoid or permanent magnets, and producing high current with low emittance, extremely high brightness is achieved. In addition to providing a small footprint and improved beam quality in an integrated structure, the compact system considerably simplifies external subsystems required to operate the photoelectron linac, including rf power transport, beam focusing, vacuum and cooling. The photoelectron linac employs an innovative Plane-Wave-Transformer (PWT) design, which provides strong cell-to-cell coupling, relaxes manufacturing tolerance and facilitates the attachment of external ports to the compact structure with minimal field interference. DULY Research Inc. under the support of the DOE Small Business Innovation Research (SBIR) program, has developed, constructed and installed a 20-MeV, S-band compact electron source at UCLA. DULY Research is also presently engaged in the development of an X-band photoelectron linear accelerator in another SBIR project. The higher frequency structure when completed will be approximately three times smaller, and capable of a beam brightness ten times higher than the S-band structure.

  14. COMPACT SCHOOL AND $$ SAVINGS.

    ERIC Educational Resources Information Center

    BAIR, W.G.

    A REVIEW OF THE CRITERIA FOR CONSIDERING THE USE OF A TOTAL ENERGY SYSTEM WITHIN A SCHOOL BUILDING STATES THE WINDOWLESS, COMPACT SCHOOL OFFERS MORE EFFICIENT SPACE UTILIZATION WITH LESS AREA REQUIRED FOR GIVEN STUDENT POPULATION AND LOWER OPERATION COSTS. THE AUTHOR RECOMMENDS THAT THESE BUILDINGS BE WINDOWLESS TO REDUCE HEAT COSTS, HOWEVER, AT…

  15. Compact optical transconductance varistor

    SciTech Connect

    Sampayan, Stephen

    2015-09-22

    A compact radiation-modulated transconductance varistor device having both a radiation source and a photoconductive wide bandgap semiconductor material (PWBSM) integrally formed on a substrate so that a single interface is formed between the radiation source and PWBSM for transmitting PWBSM activation radiation directly from the radiation source to the PWBSM.

  16. Compact ultradense matter impactors.

    PubMed

    Rafelski, Johann; Labun, Lance; Birrell, Jeremiah

    2013-03-15

    We study interactions of meteorlike compact ultradense objects (CUDO), having nuclear or greater density, with Earth and other rocky bodies in the Solar System as a possible source of information about novel forms of matter. We study the energy loss in CUDO puncture of the body and discuss differences between regular matter and CUDO impacts.

  17. WAVELENGTH CALIBRATION OF THE VLT-UVES SPECTROGRAPH

    SciTech Connect

    Whitmore, Jonathan B.; Griest, Kim; Murphy, Michael T. E-mail: mmurphy@swin.edu.a

    2010-11-01

    We attempt to measure possible miscalibration of the wavelength scale of the VLT-UVES spectrograph. We take spectra of QSO HE0515-4414 through the UVES iodine cell which contains thousands of well-calibrated iodine lines and compare these lines to the wavelength scale from the standard thorium-argon pipeline calibration. Analyzing three exposures of this z = 1.71 QSO, we find two distinct types of calibration shifts needed to correct the Th/Ar wavelength scale. First, there is an overall average velocity shift of between 100 m s{sup -1} and 500 m s{sup -1} depending upon the exposure. Second, within a given exposure, we find intra-order velocity distortions of 100 m s{sup -1} up to more than 200 m s{sup -1}. These calibration errors are similar to, but smaller than, those found earlier in the Keck HIRES spectrometer. We discuss the possible origins of these two types of miscalibration. We also explore the implications of these calibration errors on the systematic error in measurements of {Delta}{alpha}/{alpha}, the change in the fine-structure constant derived from measurement of the relative redshifts of absorption lines in QSO absorption systems. The overall average, exposure-dependent shifts should be less relevant for fine-structure work, but the intra-order shifts have the potential to affect these results. Using either our measured calibration offsets or a Gaussian model with sigma of around 90 m s{sup -1}, Monte Carlo mock experiments find errors in {Delta}{alpha}/{alpha} of between 1 x 10{sup -6} N {sup -1/2}{sub sys} and 3 x 10{sup -6} N {sup -1/2}{sub sys}, where N{sub sys} is the number of systems used and the range is due to dependence on how many metallic absorption lines in each system are compared.

  18. Engineering a highly segmented very wide-field spectrograph

    NASA Astrophysics Data System (ADS)

    Ragazzoni, R.; Fontana, A.; Maccagni, D.; Baruffolo, A.; Bianco, A. G.; diPaola, A.; Farinato, J.; Gentile, G.; Giallongo, E.; Pedichini, F.; Speziali, R.; Testa, V.

    2010-07-01

    The concept of segmenting the focal plane of an existing 8m class telescope in order to fill it with an array of several fast cameras has been developed further and in this work the status of an engineering program aimed to produce a design qualified for the construction, and to assess its cost estimates is presented. The original concept of just having simple cameras with all identical optical components other than a pupil plane corrector to remove the fixed aberrations at the off-axis field of a telescope has been extended to introduce a spectroscopic capability and to assess a trade-off between a very large number (of the order of thousand) of cameras with a small single Field of View with a smaller number of cameras able to compensate the aberration on a much larger Field of View with a combination of different optical elements and different ways to mount and align them. The scientific target of a few thousands multi-slit spectra over a Field of View of a few square degrees, combined with the ambition to mount this on an existing 8m class telescope makes the scientific rationale of such an instrument a very interesting one. In the paper we describe the different options for a possible optical design, the trade off between variations on the theme of the large segmentation and we describe briefly the way this kind of instrument can handle a multi-slit configuration. Finally, the feasibility of the components and a brief description of how the cost analysis is being performed are given. Perspectives on the construction of this spectrograph are given as well.

  19. The Goddard High Resolution Spectrograph Scientific Support Contract

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In 1988, Computer Sciences Corporation (CSC) was selected as the Goddard High Resolution Spectrograph (GHRS) Scientific Support Contractor (SSC). This was to have been a few months before the launch of NASA's first Great Observatory, the Hubble Space Telescope (HST). As one of five scientific instruments on HST, the GHRS was designed to obtain spectra in the 1050-3300 A ultraviolet wavelength region with a resolving power, lambda/Delta(lambda) , of up to 100,000 and relative photometric accuracy to 1%. It was built by Ball AeroSpace Systems Group under the guidance of the GHRS Investigation Definition Team (IDT), comprised of 16 scientists from the US and Canada. After launch, the IDT was to perform the initial instrument calibration and execute a broad scientific program during a five-year Guaranteed Time Observation (GTO) period. After a year's delay, the launch of HST occurred in April 1990, and CSC participated in the in-orbit calibration and first four years of GTO observations with the IDT. The HST primary mirror suffered from spherical aberration, which reduced the spatial and spectral resolution of Large Science Aperture (LSA) observations and decreased the throughput of the Small Science Aperture (SSA) by a factor of two. Periodic problems with the Side 1 carrousel electronics and anomalies with the low-voltage power supply finally resulted in a suspension of the use of Side 1 less than two years after launch. At the outset, the GHRS SSC task involved work in four areas: 1) to manage and operate the GHRS Data Analysis Facility (DAF); 2) to support the second Servicing Mission Observatory Verification (SMOV) program, as well as perform system engineering analysis of the GHRS as nesessary; 3) to assist the GHRS IDT with their scientific research programs, particularly the GSFC members of the team, and 4) to provide administrative and logistic support for GHRS public information and educational activities.

  20. AN INTERFACE REGION IMAGING SPECTROGRAPH FIRST VIEW ON SOLAR SPICULES

    SciTech Connect

    Pereira, T. M. D.; De Pontieu, B.; Carlsson, M.; Hansteen, V.; Tarbell, T. D.; Lemen, J.; Title, A.; Boerner, P.; Hurlburt, N.; Wülser, J. P.; Martínez-Sykora, J.; Kleint, L.; Golub, L.; McKillop, S.; Reeves, K. K.; Saar, S.; Testa, P.; Tian, H.; Jaeggli, S.; Kankelborg, C.

    2014-09-01

    Solar spicules have eluded modelers and observers for decades. Since the discovery of the more energetic type II, spicules have become a heated topic but their contribution to the energy balance of the low solar atmosphere remains unknown. Here we give a first glimpse of what quiet-Sun spicules look like when observed with NASA's recently launched Interface Region Imaging Spectrograph (IRIS). Using IRIS spectra and filtergrams that sample the chromosphere and transition region, we compare the properties and evolution of spicules as observed in a coordinated campaign with Hinode and the Atmospheric Imaging Assembly. Our IRIS observations allow us to follow the thermal evolution of type II spicules and finally confirm that the fading of Ca II H spicules appears to be caused by rapid heating to higher temperatures. The IRIS spicules do not fade but continue evolving, reaching higher and falling back down after 500-800 s. Ca II H type II spicules are thus the initial stages of violent and hotter events that mostly remain invisible in Ca II H filtergrams. These events have very different properties from type I spicules, which show lower velocities and no fading from chromospheric passbands. The IRIS spectra of spicules show the same signature as their proposed disk counterparts, reinforcing earlier work. Spectroheliograms from spectral rasters also confirm that quiet-Sun spicules originate in bushes from the magnetic network. Our results suggest that type II spicules are indeed the site of vigorous heating (to at least transition region temperatures) along extensive parts of the upward moving spicular plasma.

  1. An Airborne Infrared Telescope and Spectrograph for Solar Eclipse Observations

    NASA Astrophysics Data System (ADS)

    DeLuca, Edward E.; Cheimets, Peter; Golub, Leon

    2014-06-01

    The solar infrared spectrum offers great possibilities for direct spatially resolved measurements of the solar coronal magnetic fields, via imaging of the plasma that is constrained to follow the magnetic field direction and via spectro-polarimetry that permits measurement of the field strength in the corona. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections (CME) and provides the ultimate source of energy for space weather. The large scale structure of the coronal field, and the opening up of the field in a transition zone between the closed and open corona determines the speed and structure of the solar wind, providing the background environment through which CMEs propagate. At present our only direct measurements of the solar magnetic fields are in the photosphere and chromosphere. The ability to determine where and why the corona transitions from closed to open, combined with measurements of the field strength via infrared coronal spectro-polarimetry will give us a powerful new tool in our quest to develop the next generation of forecasting models.We describe a first step in achieving this goal: a proposal for a new IR telescope, image stabilization system, and spectrometer, for the NCAR HIPER GV aircraft. The telescope/spectrograph will operate in the 2-6micron wavelength region, during solar eclipses, starting with the trans-north American eclipse in August 2017. The HIAPER aircraft flying at ~35,000 ft will provide an excellent platform for IR observations. Our imaging and spectroscopy experiment will show the distribution and intensity of IR forbidden lines in the solar corona.

  2. A new compact laser source for portable LIBS applications

    NASA Astrophysics Data System (ADS)

    Goujon, J.; Musset, O.; Giakoumaki, A.; Pinon, V.; Anglos, D.; Georgiou, E.

    2008-02-01

    We present LIBS experimental results that demonstrate the use of a newly compact, versatile pulsed laser source in material analysis in view of research aiming at the development of portable LIBS instrumentation. LIBS qualitative analyses were performed on various samples and objects, and spectra were recorded in gated and non-gated modes. The latter is important because of advantages arising from size and cost reduction when using simple, compact spectrograph-CCD detection systems over the standard ICCD-based configurations. The new Nd 3+:YAG laser source exhibited very reliable performance in terms of laser pulse repeatability, autonomy and interface. Indeed, it can deliver a 45 mJ for 4.5 ns pulse and work at 1 Hz. Having the ability to work in double-pulse mode, it provided versatility in the measurements leading to increased LIBS signal intensities, improved the signal noise ratio and stabilized spectra. The first test results are encouraging and demonstrate that this new laser is suitable for integration in compact, portable and low cost LIBS sensors with a wide spectrum of materials analysis applications.

  3. Progress in Compact Toroid Experiments

    SciTech Connect

    Dolan, Thomas James

    2002-09-01

    The term "compact toroids" as used here means spherical tokamaks, spheromaks, and field reversed configurations, but not reversed field pinches. There are about 17 compact toroid experiments under construction or operating, with approximate parameters listed in Table 1.

  4. X-Spec: A Multi-Object Wideband Survey Spectrograph for CCAT

    NASA Astrophysics Data System (ADS)

    Bradford, Charles; Hailey-Dunsheath, S.; Shirokoff, E.; Hollister, M.; Kovacs, A.; Zmuidzinas, J.; Padin, S.; Seiffert, M. D.; Braun, D.; Banales, G.; LeDuc, H.; Stacey, G. J.; Nikola, T.; Glenn, J.; Chapman, S.

    2013-01-01

    We are developing a multi-object dispersive survey spectrograph for CCAT. X-Spec is optimized for rest-frame far-IR / submm atomic and molecular transitions in high-z galaxies, and it will conduct multi-galaxy spectral survey up to 10x faster than ALMA. Detected lines will provide redshifts for and interstellar gas conditions in tens of thousands of galaxies ranging from the early universe (z > 6) to the present day. X-Spec will be particularly sensitive to the 158-micron ionized carbon fine-structure transition [CII], and the initial instrument will target the 650-um, 850-um, and 1-mm atmospheric windows, corresponding to 3.5 to 9 for [CII]. By following up high-z candidate objects, X-Spec surveys of [CII] will reveal the early evolution of galaxies' energy sources and interstellar gas conditions. CCAT/X-Spec can also probe below individually-detected sources by using fluctuation analyses; the spatial-spectral fluctuations mm and submm bands are dominated by [CII], and can be used to measure the growth of large-scale structure and the global properties of galaxies in the reionization epoch. X-Spec will have at least 15 independent spectrometer backend 'pixels', each covering 195-520 GHz instantaneously at R=400-700, in both polarizations with photon-background-limited sensitivity. It will use lithographically-patterned filterbank chips formed with superconducting transmission line. The detectors are titanium-nitride kinetic inductance detectors (KIDs), and each spectrometer chip will have ~500 KIDs integrated with the filterbank in a package a few square cm in size. Each chip has a bandwidth of ~ 1:1.6 and is single-polarization, so coverage of the full 195-520 GHz range in dual-pol requires 4 chips and ~2000 detectors. With the compact size and inexpensive mass production, much larger spectrometer formats (100-300 pixels) will be possible as detector readout technology progresses. To optimize on-source observation efficiency, a 2-axis rotary positioning system

  5. The Evolutionary State of the Pre-main Sequence Population in Ophiuchus: A Large Infrared Spectrograph Survey

    NASA Astrophysics Data System (ADS)

    McClure, M. K.; Furlan, E.; Manoj, P.; Luhman, K. L.; Watson, D. M.; Forrest, W. J.; Espaillat, C.; Calvet, N.; D'Alessio, P.; Sargent, B.; Tobin, J. J.; Chiang, Hsin-Fang

    2010-05-01

    Variations in molecular cloud environments have the potential to affect the composition and structure of the circumstellar disks therein. To this end, comparative analyses of nearby star-forming regions are essential to informing theoretical work. In particular, the Ophiuchus molecular clouds are ideal for comparison as they are more compact with much higher extinction than Taurus, the low-mass exemplar, and experience a moderate amount of external radiation. We have carried out a study of a collection of 136 young stellar objects in the <1 Myr old Ophiuchus star-forming region, featuring Spitzer Infrared Spectrograph spectra from 5 to 36 μm, supplemented with photometry from 0.3 μm to 1.3 mm. By classifying these objects using the McClure new molecular cloud extinction law to establish an extinction-independent index, we arrive at a ~10% embedded objects fraction, producing an embedded lifetime of 0.2 Myr, similar to that in Taurus. We analyze the degree of dust sedimentation and dust grain processing in the disks, finding that the disks are highly settled with signs of significant dust processing even at ~0.3 Myr. Finally, we discuss the wealth of evidence for radial gap structures which could be evidence for disk-planet interactions and explore the effects of stellar multiplicity on the degree of settling and radial structure.

  6. THE EVOLUTIONARY STATE OF THE PRE-MAIN SEQUENCE POPULATION IN OPHIUCHUS: A LARGE INFRARED SPECTROGRAPH SURVEY

    SciTech Connect

    McClure, M. K.; Espaillat, C.; Calvet, N.; Tobin, J. J. E-mail: ccespa@umich.ed E-mail: jjtobin@umich.ed

    2010-05-15

    Variations in molecular cloud environments have the potential to affect the composition and structure of the circumstellar disks therein. To this end, comparative analyses of nearby star-forming regions are essential to informing theoretical work. In particular, the Ophiuchus molecular clouds are ideal for comparison as they are more compact with much higher extinction than Taurus, the low-mass exemplar, and experience a moderate amount of external radiation. We have carried out a study of a collection of 136 young stellar objects in the <1 Myr old Ophiuchus star-forming region, featuring Spitzer Infrared Spectrograph spectra from 5 to 36 {mu}m, supplemented with photometry from 0.3 {mu}m to 1.3 mm. By classifying these objects using the McClure new molecular cloud extinction law to establish an extinction-independent index, we arrive at a {approx}10% embedded objects fraction, producing an embedded lifetime of 0.2 Myr, similar to that in Taurus. We analyze the degree of dust sedimentation and dust grain processing in the disks, finding that the disks are highly settled with signs of significant dust processing even at {approx}0.3 Myr. Finally, we discuss the wealth of evidence for radial gap structures which could be evidence for disk-planet interactions and explore the effects of stellar multiplicity on the degree of settling and radial structure.

  7. Compact Spreader Schemes

    SciTech Connect

    Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

    2014-07-25

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  8. Compact torsatron reactors

    SciTech Connect

    Lyon, J.F.; Carreras, B.A.; Lynch, V.E.; Tolliver, J.S.; Sviatoslavsky, I.N.

    1988-05-01

    Low-aspect-ratio torsatron configurations could lead to compact stellarator reactors with R/sub 0/ = 8--11m, roughly one-half to one-third the size of more conventional stellarator reactor designs. Minimum-size torsatron reactors are found using various assumptions. Their size is relatively insensitive to the choice of the conductor parameters and depends mostly on geometrical constraints. The smallest size is obtained by eliminating the tritium breeding blanket under the helical winding on the inboard side and by reducing the radial depth of the superconducting coil. Engineering design issues and reactor performance are examined for three examples to illustrate the feasibility of this approach for compact reactors and for a medium-size (R/sub 0/ approx. = 4 m,/bar a/ /approx lt/ 1 m) copper-coil ignition experiment. 26 refs., 11 figs., 7 tabs.

  9. Compact spreader schemes

    NASA Astrophysics Data System (ADS)

    Placidi, M.; Jung, J.-Y.; Ratti, A.; Sun, C.

    2014-12-01

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  10. Super-Compact Laser

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Microcosm, Inc. produced the portable Farfield-2 laser for field applications that require high power pulsed illumination. The compact design was conceived through research at Goddard Space Flight Center on laser instruments for space missions to carry out geoscience studies of Earth. An exclusive license to the key NASA patent for the compact laser design was assigned to Microcosm. The FarField-2 is ideal for field applications, has low power consumption, does not need water cooling or gas supplies, and produces nearly ideal beam quality. The properties of the laser also make it effective over long distances, which is one reason why NASA developed the technology for laser altimeters that can be toted aboard spacecraft. Applications for the FarField-2 include medicine, biology, and materials science and processing, as well as diamond marking, semiconductor line-cutting, chromosome surgery, and fluorescence microscopy.

  11. CAFE: Calar Alto Fiber-fed Echelle spectrograph

    NASA Astrophysics Data System (ADS)

    Sánchez, S. F.; Aceituno, J.; Thiele, U.; Grupp, F.; Dreizler, S.; Bean, J.; Benitez, D.

    2011-11-01

    The Calar Alto Fiber-fed Echelle spectrograph (CAFE) is an instrument underconstruction at CAHA to replace FOCES, the high-resolution echellespectrograph at the 2.2 m telescope of the observatory. FOCES is a property ofthe Observatory of the Munich University, and it was recalled it from Calar Altoin 2009. The instrument comprised a substantial fraction of thetelescope time during its operational life-time, and it is due to that it wastaken the decision to build a replacement.CAFE shares its basic characteristics with those of FOCES. However, significantimprovements have been introduced in the original design, the quality of thematerials, and the overall stability of the system. In particular: (i) a newcalibration Iodine cell is foreseen to operate together with the standard ThArlamps; (ii) the optical quality of all the components has been selected to belambda/20, instead of the original lambda/10; (iii) an isolated room hasbeen selected to place the instrument, termalized and stabilized againstvibrations (extensive tests have been performed to grant the stability); (iv)most of the mobile parts in FOCES has been substituted by fixed elements, toincrease the stability of the system; and finally (v) a new more efficientCCD, with a smaller pixel has been acquired. It is expected that the overallefficiency and the quality of the data will be significantly improved withrespect to its precesor. In particular, CAFE is design and built to achieveresolutions of R ˜ 70000, which will be kept in the final acquired data,allowing it to compete with current operational extrasolar planets hunters.After two years of work all the components are in place. The instrument is nowfinally assembled, and we are performing the the first alignment tests. It isexpected that the commissioning on the laboratory will finish at the end of2010, followed by the commissioning on telescope along the first semester of2011. If everything goes well, we will offer the instrument in a shared

  12. Compact power reactor

    DOEpatents

    Wetch, Joseph R.; Dieckamp, Herman M.; Wilson, Lewis A.

    1978-01-01

    There is disclosed a small compact nuclear reactor operating in the epithermal neutron energy range for supplying power at remote locations, as for a satellite. The core contains fuel moderator elements of Zr hydride with 7 w/o of 93% enriched uranium alloy. The core has a radial beryllium reflector and is cooled by liquid metal coolant such as NaK. The reactor is controlled and shut down by moving portions of the reflector.

  13. Hydraulic conductivity of compacted zeolites.

    PubMed

    Oren, A Hakan; Ozdamar, Tuğçe

    2013-06-01

    Hydraulic conductivities of compacted zeolites were investigated as a function of compaction water content and zeolite particle size. Initially, the compaction characteristics of zeolites were determined. The compaction test results showed that maximum dry unit weight (γ(dmax)) of fine zeolite was greater than that of granular zeolites. The γ(dmax) of compacted zeolites was between 1.01 and 1.17 Mg m(-3) and optimum water content (w(opt)) was between 38% and 53%. Regardless of zeolite particle size, compacted zeolites had low γ(dmax) and high w(opt) when compared with compacted natural soils. Then, hydraulic conductivity tests were run on compacted zeolites. The hydraulic conductivity values were within the range of 2.0 × 10(-3) cm s(-1) to 1.1 × 10(-7) cm s(-1). Hydraulic conductivity of all compacted zeolites decreased almost 50 times as the water content increased. It is noteworthy that hydraulic conductivity of compacted zeolite was strongly dependent on the zeolite particle size. The hydraulic conductivity decreased almost three orders of magnitude up to 39% fine content; then, it remained almost unchanged beyond 39%. Only one report was found in the literature on the hydraulic conductivity of compacted zeolite, which is in agreement with the findings of this study.

  14. The cryogenic system for the VIRUS array of spectrographs on the Hobby-Eberly Telescope

    NASA Astrophysics Data System (ADS)

    Smith, Michael P.; Mulholland, George T.; Booth, John A.; Good, John M.; Hill, Gary J.; MacQueen, Phillip J.; Rafal, Marc D.; Savage, Richard D.; Vattiat, Brian L.

    2008-07-01

    The Hobby-Eberly Telescope (HET) is an existing innovative large telescope of 9.2 meter aperture, located at the McDonald Observatory in West Texas. The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) requires a major upgrade to the HET, including a substantial increase in the telescope field of view, as well as the development and integration of a revolutionary new integral field spectrograph called VIRUS. The Visible Integral-Field Replicable Unit Spectrograph (VIRUS) is an instrument comprising approximately 150 individual IFU-fed spectrographs which will be mounted on the telescope structure. Each spectrograph has a CDD camera detector package which must be cryogenically cooled during scientific operation. In order to cool each of these camera systems a liquid nitrogen system has been proposed and design study completed. The proposed system includes: a liquid nitrogen source, vacuum jacket distribution system, local storage on the telescope, and distribution under a thermal siphon to the individual spectrographs and local thermal connectors.

  15. The problem of scattering in fibre-fed VPH spectrographs and possible solutions

    NASA Astrophysics Data System (ADS)

    Ellis, S. C.; Saunders, Will; Betters, Chris; Croom, Scott

    2014-07-01

    All spectrographs unavoidably scatter light. Scattering in the spectral direction is problematic for sky subtraction, since atmospheric spectral lines are blurred. Scattering in the spatial direction is problematic for fibre fed spectrographs, since it limits how closely fibres can be packed together. We investigate the nature of this scattering and show that the scattering wings have both a Lorentzian component, and a shallower (1/r) component. We investigate the causes of this from a theoretical perspective, and argue that for the spectral PSF the Lorentzian wings are in part due to the profile of the illumination of the pupil of the spectrograph onto the diffraction grating, whereas the shallower component is from bulk scattering. We then investigate ways to mitigate the diffractive scattering by apodising the pupil. In the ideal case of a Gaussian apodised pupil, the scattering can be significantly improved. Finally we look at realistic models of the spectrograph pupils of fibre fed spectrographs with a centrally obstructed telescope, and show that it is possible to apodise the pupil through non-telecentric injection into the fibre.

  16. Stray light performance of a combined monochromator-spectrograph UV irradiance measuring instrument

    NASA Astrophysics Data System (ADS)

    Forment, S.; Hanselaer, P.

    2010-08-01

    Critical UV applications such as disinfections and dermatological treatments call for accurate UV spectral irradiation measurements. Single monochromators and spectrographs are not able to provide satisfying accuracy due to poor stray light rejection. The main drawbacks of a double monochromator scanning system are the need for motion synchronization, the inconvenience in performing field measurements and the time-consuming scanning approach. In this paper, a combination of a monochromator with a large bandpass and a spectrograph is proposed, which allows for accurate UV spectral irradiance measurements with short measurement times of less than 1 s, and yet with acceptable stray light rejection. Stray light levels are determined for both monochromatic and heterochromatic primary radiation using slit functions and cut-off filters. These experiments revealed a considerable UV stray light response reduction for the monochromator-spectrograph combination compared to single spectrograph instruments. The stray light performance in the 250-400 nm range matches with results obtained with double monochromator instruments. With this setup, the quality of a double dispersing instrument is combined with the quick data acquisition of a spectrograph.

  17. A Cross-Dispersed Medium-Resolution Spectrograph for Appalachian State Univeristy's 32-inch Telescope

    NASA Astrophysics Data System (ADS)

    Kluttz, K. A.; Gray, R. O.

    2003-12-01

    We have designed and constructed an economical medium-resolution spectrograph to be used on the 32-inch telescope of Appalachian State University's Dark Sky Observatory (DSO). The primary function of this instrument will be to study shell and emission-line stars. However, we will also use this instrument for chemical abundance studies and radial velocities. The basic design is that of an Ebert spectrograph with a single 6-inch mirror acting as both the collimator and camera. The primary dispersion is accomplished by a reflection grating, and order separation is accomplished by a grism. The spectrograph has been designed so that three wavelength regions are simultaneously imaged on the CCD camera. When the Hα line is centered in the third order, Hβ and lines of Fe II multiplet 42 -- often enhanced in shell and emission-line stars -- appear in the fourth order and the fifth order contains both the Ca II K & H lines. To facilitate abundance measurements, a telluric-free region near 6400Å is available in the third order by tilting the main diffraction grating. Preliminary tests have shown that the resolution of the new spectrograph is 0.42Å in the third order (R ≈ 15,000). This relatively high resolution will allow studies to be conducted at DSO which have not previously been possible with the instrumentation currently in use. Several optical components for this spectrograph were purchased with grants from the Fund for Astrophysical Research and the University Research Council.

  18. Compact far ultraviolet emission source with rich spectral emission 1150-3100 A. [Pt hollow cathode

    NASA Technical Reports Server (NTRS)

    Mount, G. H.; Fastie, W. G.; Yamasaki, G.; Fowler, W.

    1977-01-01

    The article describes a compact hollow Pt cathode emission source for the far UV, developed for use as a high-resolution wavelength standard in laboratory work or on spacecraft (specifically, the NASA International UV Explorer - IUE). The source is small, rugged, lightweight, spectrally rich, bright in the 1150-3200 A region, features long service life, low operating voltage, and lower power drain, and stably emits a large number of very sharp lines with a spectrum lending itself to projection onto the focal plane of a spectrograph. The source has successfully passed exacting environmental tests, and serves as a transfer standard for absolute sensitivity calibration of spectrometric instruments.

  19. Compact gate valve

    DOEpatents

    Bobo, Gerald E.

    1977-01-01

    This invention relates to a double-disc gate valve which is compact, comparatively simple to construct, and capable of maintaining high closing pressures on the valve discs with low frictional forces. The valve casing includes axially aligned ports. Mounted in the casing is a sealed chamber which is pivotable transversely of the axis of the ports. The chamber contains the levers for moving the valve discs axially, and an actuator for the levers. When an external drive means pivots the chamber to a position where the discs are between the ports and axially aligned therewith, the actuator for the levers is energized to move the discs into sealing engagement with the ports.

  20. COMPACT CASCADE IMPACTS

    DOEpatents

    Lippmann, M.

    1964-04-01

    A cascade particle impactor capable of collecting particles and distributing them according to size is described. In addition the device is capable of collecting on a pair of slides a series of different samples so that less time is required for the changing of slides. Other features of the device are its compactness and its ruggedness making it useful under field conditions. Essentially the unit consists of a main body with a series of transverse jets discharging on a pair of parallel, spaced glass plates. The plates are capable of being moved incremental in steps to obtain the multiple samples. (AEC)

  1. Compact laser amplifier system

    DOEpatents

    Carr, R.B.

    1974-02-26

    A compact laser amplifier system is described in which a plurality of face-pumped annular disks, aligned along a common axis, independently radially amplify a stimulating light pulse. Partially reflective or lasing means, coaxially positioned at the center of each annualar disk, radially deflects a stimulating light directed down the common axis uniformly into each disk for amplification, such that the light is amplified by the disks in a parallel manner. Circumferential reflecting means coaxially disposed around each disk directs amplified light emission, either toward a common point or in a common direction. (Official Gazette)

  2. Compact Q-balls

    NASA Astrophysics Data System (ADS)

    Bazeia, D.; Losano, L.; Marques, M. A.; Menezes, R.; da Rocha, R.

    2016-07-01

    In this work we deal with non-topological solutions of the Q-ball type in two space-time dimensions, in models described by a single complex scalar field that engenders global symmetry. The main novelty is the presence of stable Q-balls solutions that live in a compact interval of the real line and appear from a family of models controlled by two distinct parameters. We find analytical solutions and study their charge and energy, and show how to control the parameters to make the Q-balls classically and quantum mechanically stable.

  3. Compact Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2004-01-01

    A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

  4. Compact LINAC for deuterons

    SciTech Connect

    Kurennoy, S S; O' Hara, J F; Rybarcyk, L J

    2008-01-01

    We are developing a compact deuteron-beam accelerator up to the deuteron energy of a few MeV based on room-temperature inter-digital H-mode (IH) accelerating structures with the transverse beam focusing using permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we show that IHPMQ structures provide very efficient and practical accelerators for light-ion beams of considerable currents at the beam velocities around a few percent of the speed of light. IH-structures with PMQ focusing following a short RFQ can also be beneficial in the front end of ion linacs.

  5. NIRMOS: a wide-field near-infrared spectrograph for the Giant Magellan Telescope

    NASA Astrophysics Data System (ADS)

    Fabricant, Daniel; Fata, Robert; Brown, Warren R.; McLeod, Brian; Mueller, Mark; Gauron, Thomas; Roll, John; Bergner, Henry; Geary, John; Kradinov, Vladimir; Norton, Tim; Smith, Matt; Zajac, Joseph

    2012-09-01

    NIRMOS (Near-Infrared Multiple Object Spectrograph) is a 0.9 to 2.5 μm imager/spectrograph concept proposed for the Giant Magellan Telescope1 (GMT). Near-infrared observations will play a central role in the ELT era, allowing us to trace the birth and evolution of galaxies through the era of peak star formation. NIRMOS' large field of view, 6.5′ by 6.5′, will be unique among imaging spectrographs developed for ELTs. NIRMOS will operate in Las Campanas' superb natural seeing and is also designed to take advantage of GMT's ground-layer adaptive optics system. We describe NIRMOS' high-performance optical and mechanical design.

  6. Performance of a laser frequency comb calibration system with a high-resolution solar echelle spectrograph

    NASA Astrophysics Data System (ADS)

    Doerr, H.-P.; Kentischer, T. J.; Steinmetz, T.; Probst, R. A.; Franz, M.; Holzwarth, R.; Udem, Th.; Hänsch, T. W.; Schmidt, W.

    2012-09-01

    Laser frequency combs (LFC) provide a direct link between the radio frequency (RF) and the optical frequency regime. The comb-like spectrum of an LFC is formed by exact equidistant laser modes, whose absolute optical frequencies are controlled by RF-references such as atomic clocks or GPS receivers. While nowadays LFCs are routinely used in metrological and spectroscopic fields, their application in astronomy was delayed until recently when systems became available with a mode spacing and wavelength coverage suitable for calibration of astronomical spectrographs. We developed a LFC based calibration system for the high-resolution echelle spectrograph at the German Vacuum Tower Telescope (VTT), located at the Teide observatory, Tenerife, Canary Islands. To characterize the calibration performance of the instrument, we use an all-fiber setup where sunlight and calibration light are fed to the spectrograph by the same single-mode fiber, eliminating systematic effects related to variable grating illumination.

  7. Multi-mode spectrographs for small telescopes: design, operation, performances and results

    NASA Astrophysics Data System (ADS)

    Munari, U.; Valisa, P.

    2014-03-01

    We present three generations (Mark.I, II and III) of spectrographs we put into operation with ANS Collaboration 0.61m, 0.70m and 0.84m telescopes. These spectrographs are of the Multi-Mode type, allowing for rapid interchange between Echelle high dispersion and two separate single dispersion modes (low and medium resolution). All three modes are long-slit, rotate to any angle (including parallactic compensation for atmospheric dispersion), allow to select among different comparison lamps, and are auto-guided by TV imaging the slit, which is continuously adjustable in width and by a step decker in height. The latest Mark.III model adds many new features including remote operation, spatial splitting of order overlap in single dispersion modes, interchange between prism and grating cross-dispersion in the Echelle mode, spectropolarimetry, a coronagraphic mode and direct filtered imaging without removing the spectrograph from the Cassegrain focus.

  8. UV CCD detectors for WUVS spectrographs of WSO-UV project

    NASA Astrophysics Data System (ADS)

    Shugarov, Andrey; Sachkov, Mikhail; Savanov, Igor; Jaeger, Andreas; Jerram, Paul

    WUVS (WSO-UV Ultra Violet Spectrographs) consists of two high resolution spectrographs (R=50000) covering the Far-UV range of 115-176 nm and the Near-UV range of 174-310 nm, and a long-slit spectrograph (R=1000) covering the wavelength range of 115-305 nm. CCDs for WUVS will be optimized to operate at low level signals. CCD chips with no AR coating for FUV range (<200 nm) and AR coating for NUV range (>200 nm) will be manufactured by e2v company using the enhanced backthinned process. Detectors will operate at the temperature of 173 K with 600 s standard integration time. CCD detectors are optimized for low read-out noise (less than 3e-) and low dark current. The main parameters of WUVS detector subsystems are described.

  9. Development of the MAMA Detectors for the Hubble Space Telescope Imaging Spectrograph

    NASA Technical Reports Server (NTRS)

    Timothy, J. Gethyn

    1997-01-01

    The development of the Multi-Anode Microchannel Array (MAMA) detector systems started in the early 1970's in order to produce multi-element detector arrays for use in spectrographs for solar studies from the Skylab-B mission. Development of the MAMA detectors for spectrographs on the Hubble Space Telescope (HST) began in the late 1970's, and reached its culmination with the successful installation of the Space Telescope Imaging Spectrograph (STIS) on the second HST servicing mission (STS-82 launched 11 February 1997). Under NASA Contract NAS5-29389 from December 1986 through June 1994 we supported the development of the MAMA detectors for STIS, including complementary sounding rocket and ground-based research programs. This final report describes the results of the MAMA detector development program for STIS.

  10. A compact SADM family

    NASA Astrophysics Data System (ADS)

    Barbet, Vincent; Le Quintrec, Cyrille; Jeandot, Xavier; Chaix, Alain; Grain, Eric; Roux, Jerome

    2005-07-01

    Alcatel Space has developed a new SADM family driven by cost, modularity, mass and performances. The modularity concept is based on separating the rotation drive function from the electrical transfer function. The drive actuator has been designed for various applications where pointing and reliability is needed. It can be associated with high dissipative rotary devices (SA collectors, RF joints..). The design goal was to minimize the number of parts in order to reach the most simple and compact mechanism. Mass reduction was achieved by reducing as much as possible the load path between the Solar Array interface and the spacecraft interface. Following these guidelines, the drive actuator was developed and qualified on ATV SADM (part od Alcatel Space Solar Array Drive Sub System for ATV). Further more a high power integrated collector was qualified inside the SADM for Geo-stationary telecom satellite (SPACEBUS platforms). Fine thermal and mechanical modeling was necessary to predict SADM behaviors for the numerous thermal environments over the missions (steady and transient cases). These modeling were well correlated through mechanical and thermal balances qualification tests. The challenging approach of thermal dissipation in a compact design leads to a family of 3 SADM capabilities form 2kW up to 15kW per SADM weighing less than 4.5 kg each.

  11. Compaction of Titanium Powders

    SciTech Connect

    Stephen J. Gerdemann; Paul D. Jablonski

    2010-11-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines <150 μm, <75 μm, and < 45 μm; two different sizes of a hydride-dehydride [HDH] <75 μm and < 45 μm; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  12. Compaction of Titanium Powders

    NASA Astrophysics Data System (ADS)

    Gerdemann, Stephen J.; Jablonski, Paul D.

    2011-05-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines <150 μm, <75 μm, and < 45 μm; two different sizes of a hydride-dehydride [HDH] <75 μm and < 45 μm; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  13. Field application of moment-based wavefront sensing to in-situ alignment and image quality assessment of astronomical spectrographs: results and analysis of aligning VIRUS unit spectrographs

    NASA Astrophysics Data System (ADS)

    Lee, Hanshin; Hill, Gary J.; Tuttle, Sarah E.; Noyola, Eva; Peterson, Trent; Vattiat, Brian L.

    2014-07-01

    Teague introduced a phase retrieval method that uses the image shape moments. More recently, an independent study arrived at a similar technique, which was then applied to in-situ full-field image-quality evaluation of spectroscopic systems. This moment-based wavefront sensing (MWFS) method relies on the geometric relation between the image shape moments and the geometric wavefront modal coefficients. The MWFS method allows a non-iterative determination of the modal coefficients from focus-modulated images at arbitrary spatial resolutions. The determination of image moments is a direct extension of routine centroid and image size calculation, making its implementation easy. Previous studies showed that the MWFS works well in capturing large low-order modes, and is quite suitable for in-situ alignment diagnostics. At the Astronomical Instrumentation conference in 2012, we presented initial results of the application of the moment-based wavefront sensing to a fiber-fed astronomical spectrograph, called VIRUS (a set of replicated 150 identical integral-field unit spectrographs contained in 75 unit pairs). This initial result shows that the MWFS can provide accurate full-field image-quality assessment for efficiently aligning these 150 spectrographs. Since then, we have assembled more than 24 unit pairs using this technique. In this paper, we detail the technical update/progress made so far for the moment-based wavefront sensing method and the statistical estimates of the before/after alignment aberrations, image-quality, and various efficiency indicators of the unit spectrograph alignment process.

  14. Performance testing of an off-plane reflection grating and silicon pore optic spectrograph at PANTER

    NASA Astrophysics Data System (ADS)

    Marlowe, Hannah; McEntaffer, Randall L.; Allured, Ryan; DeRoo, Casey T.; Donovan, Benjamin D.; Miles, Drew M.; Tutt, James H.; Burwitz, Vadim; Menz, Benedikt; Hartner, Gisela D.; Smith, Randall K.; Cheimets, Peter; Hertz, Edward; Bookbinder, Jay A.; Günther, Ramses; Yanson, Alex; Vacanti, Giuseppe; Ackermann, Marcelo

    2015-10-01

    An x-ray spectrograph consisting of aligned, radially ruled off-plane reflection gratings and silicon pore optics (SPO) was tested at the Max Planck Institute for Extraterrestrial Physics PANTER x-ray test facility. SPO is a test module for the proposed Arcus mission, which will also feature aligned off-plane reflection gratings. This test is the first time two off-plane gratings were actively aligned to each other and with an SPO to produce an overlapped spectrum. We report the performance of the complete spectrograph utilizing the aligned gratings module and plans for future development.

  15. HIRDES-The High-Resolution Double-Echelle Spectrograph for WSO-UV

    NASA Astrophysics Data System (ADS)

    Werner, Klaus; Barnstedt, Jürgen; Kappelmann, Norbert; Becker-Roß, Helmut; Florek, Stefan

    2009-05-01

    We introduce the High-Resolution Double-Echelle Spectrograph (HIRDES), which is planned to be the main instrument for the World Space Observatory Ultraviolet (WSO-UV), a 1.7 m UV telescope. Within HIRDES the 102-310 nm spectral band is split to feed two echelle spectrographs covering the UV range 174-310 nm and the vacuum-UV range 102-176 nm with high spectral resolution (R>50000). The technical concept is based on the heritage of two previous ORFEUS SPAS missions. We describe results of the phase-B1 development activities.

  16. Optimised target allocation algorithm for multi-fibre fed spectrographs at E-ELT

    NASA Astrophysics Data System (ADS)

    Rota, S.; Garilli, B.

    In fibre-fed multi-object spectrograph, an optimised algorithm is necessary to maximise the number of allocated fibres on pre-selected targets and decrease the number of unused fibres during each observation. We present some criteria in the assignment of targets to fibres in order to obtain an optimised solution between several possible configurations. We also consider a particular situation in which half of the fibres are allocated on targets and the other half is used to observe sky positions. Applying the algorithm to the known distribution of {˜ 1000} fibres of the MOONS spectrograph, we obtain encouraging results.

  17. The On-Orbit Performance of the Space Telescope Imaging Spectrograph

    NASA Astrophysics Data System (ADS)

    Kimble, R. A.; Woodgate, B. E.; Bowers, C. W.; Kraemer, S. B.; Kaiser, M. E.; Gull, T. R.; Heap, S. R.; Danks, A. C.; Boggess, A.; Green, R. F.; Hutchings, J. B.; Jenkins, E. B.; Joseph, C. L.; Linsky, J. L.; Maran, S. P.; Moos, H. W.; Roesler, F.; Timothy, J. G.; Weistrop, D. E.; Grady, J. F.; Loiacono, J. J.; Brown, L. W.; Brumfield, M. D.; Content, D. A.; Feinberg, L. D.; Isaacs, M. N.; Krebs, C. A.; Krueger, V. L.; Melcher, R. W.; Rebar, F. J.; Vitagliano, H. D.; Yagelowich, J. J.; Meyer, W. W.; Hood, D. F.; Argabright, V. S.; Becker, S. I.; Bottema, M.; Breyer, R. R.; Bybee, R. L.; Christon, P. R.; Delamere, A. W.; Dorn, D. A.; Downey, S.; Driggers, P. A.; Ebbets, D. C.; Gallegos, J. S.; Garner, H.; Hetlinger, J. C.; Lettieri, R. L.; Ludtke, C. W.; Michika, D.; Nyquist, R.; Rose, D. M.; Stocker, R. B.; Sullivan, J. F.; Van Houten, C. N.; Woodruff, R. A.; Baum, S. A.; Hartig, G. F.; Balzano, V.; Biagetti, C.; Blades, J. C.; Bohlin, R. C.; Clampin, M.; Doxsey, R.; Ferguson, H. C.; Goudfrooij, P.; Hulbert, S. J.; Kutina, R.; McGrath, M.; Lindler, D. J.; Beck, T. L.; Feggans, J. K.; Plait, P. C.; Sandoval, J. L.; Hill, R. S.; Collins, N. R.; Cornett, R. H.; Fowler, W. B.; Hill, R. J.; Landsman, W. B.; Malumuth, E. M.; Standley, C.; Blouke, M.; Grusczak, A.; Reed, R.; Robinson, R. D.; Valenti, J. A.; Wolfe, T.

    1998-01-01

    The Space Telescope Imaging Spectrograph (STIS) was successfully installed into the Hubble Space Telescope (HST) in 1997 February, during the second HST servicing mission, STS-82. STIS is a versatile spectrograph, covering the 115-1000 nm wavelength range in a variety of spectroscopic and imaging modes that take advantage of the angular resolution, unobstructed wavelength coverage, and dark sky offered by the HST. In the months since launch, a number of performance tests and calibrations have been carried out and are continuing. These tests demonstrate that the instrument is performing very well. We present here a synopsis of the results to date.

  18. AVES-IMCO: an adaptive optics visible spectrograph and imager/coronograph for NAOS

    NASA Astrophysics Data System (ADS)

    Beuzit, Jean-Luc; Lagrange, A.-M.; Mouillet, D.; Chauvin, G.; Stadler, E.; Charton, J.; Lacombe, F.; AVES-IMCO Team

    2001-05-01

    The NAOS adaptive optics system will very soon provide diffraction-limited images on the VLT, down to the visible wavelengths (0.020 arcseconds at 0.83 micron for instance). At the moment, the only instrument dedicated to NAOS is the CONICA spectro-imager, operating in the near-infrared from 1 to 5 microns. We are now proposing to ESO, in collaboration with an Italian group, the development of a visible spectrograph/imager/coronograph, AVES-IMCO (Adaptive Optics Visual Echelle Spectrograph and IMager/COronograph). We present here the general concept of the new instrument as well as its expected performances in the different modes.

  19. The SCR flare of 16 February 1984 as recorded by the Sayan spectrograph

    NASA Technical Reports Server (NTRS)

    Koslov, S. A.; Pakhomov, N. I.; Shapovalova, L. A.; Yanchukovsky, A. L.

    1985-01-01

    The Sayan cosmic ray (CR) spectrograph recorded an SCR flare that occurred on 16 February 1984. Data from both 1-hour and 110-minute duration measurements in 10 channels with different energy sensitivity (of neutron monitors HM-64 located at different depths in the atmosphere, and of a neutron, multiple neutron and rigid mumeson component lead-less detector) is presented. The parameters of the SCR variation spectrum are evaluated and it is shown that the recording of multiple neutrons at the same geographic point and at the same level in the atmosphere provides information similar to that from a spectrographic complex of instruments.

  20. METHOD OF FORMING ELONGATED COMPACTS

    DOEpatents

    Larson, H.F.

    1959-05-01

    A powder compacting procedure and apparatus which produces elongated compacts of Be is described. The powdered metal is placed in a thin metal tube which is chemically compatible to lubricant, powder, atmosphere, and die material and will undergo a high degree of plastic deformation and have intermediate hardness. The tube is capped and placed in the die, and punches are applied to the ends. During the compacting stroke the powder seizes the tube and a thickening and shortening of the tube occurs. The tube is easily removed from the die, split, and peeled from the compact. (T.R.H.)

  1. Compact acoustic refrigerator

    SciTech Connect

    Bennett, G.A.

    1991-12-31

    This invention is comprised of a compact acoustic refrigeration system that actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment.

  2. Compact vacuum insulation embodiments

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1992-01-01

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  3. Compact vacuum insulation

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1993-01-01

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  4. Compact acoustic refrigerator

    DOEpatents

    Bennett, G.A.

    1992-11-24

    A compact acoustic refrigeration system actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment. 18 figs.

  5. Multipurpose Compact Spectrometric Unit

    SciTech Connect

    Bocarov, Viktor; Cermak, Pavel; Mamedov, Fadahat; Stekl, Ivan

    2009-11-09

    A new standalone compact spectrometer was developed. The device consists of analog (peamplifier, amplifier) and digital parts. The digital part is based on the 160 MIPS Digital Signal Processor. It contains 20 Msps Flash-ADC, 1 MB RAM for spectra storage, 128 KB Flash/ROM for firmware storage, Real Time Clock and several voltage regulators providing the power for user peripherals (e.g. amplifier, temperature sensors, etc.). Spectrometer is connected with a notebook via high-speed USB 2.0 bus. The spectrometer is multipurpose device, which is planned to be used for measurements of Rn activities, energy of detected particles by CdTe pixel detector or for coincidence measurements.

  6. Multipurpose Compact Spectrometric Unit

    NASA Astrophysics Data System (ADS)

    Bočarov, Viktor; Čermák, Pavel; Mamedov, Fadahat; Štekl, Ivan

    2009-11-01

    A new standalone compact spectrometer was developed. The device consists of analog (peamplifier, amplifier) and digital parts. The digital part is based on the 160 MIPS Digital Signal Processor. It contains 20 Msps Flash-ADC, 1 MB RAM for spectra storage, 128 KB Flash/ROM for firmware storage, Real Time Clock and several voltage regulators providing the power for user peripherals (e.g. amplifier, temperature sensors, etc.). Spectrometer is connected with a notebook via high-speed USB 2.0 bus. The spectrometer is multipurpose device, which is planned to be used for measurements of Rn activities, energy of detected particles by CdTe pixel detector or for coincidence measurements.

  7. Compact vacuum insulation embodiments

    DOEpatents

    Benson, D.K.; Potter, T.F.

    1992-04-28

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

  8. Compact vacuum insulation

    DOEpatents

    Benson, D.K.; Potter, T.F.

    1993-01-05

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  9. Compact acoustic refrigerator

    DOEpatents

    Bennett, Gloria A.

    1992-01-01

    A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.

  10. Compact reactor design automation

    NASA Technical Reports Server (NTRS)

    Nassersharif, Bahram; Gaeta, Michael J.

    1991-01-01

    A conceptual compact reactor design automation experiment was performed using the real-time expert system G2. The purpose of this experiment was to investigate the utility of an expert system in design; in particular, reactor design. The experiment consisted of the automation and integration of two design phases: reactor neutronic design and fuel pin design. The utility of this approach is shown using simple examples of formulating rules to ensure design parameter consistency between the two design phases. The ability of G2 to communicate with external programs even across networks provides the system with the capability of supplementing the knowledge processing features with conventional canned programs with possible applications for realistic iterative design tools.

  11. Compact artificial hand

    NASA Technical Reports Server (NTRS)

    Wiker, G. A.; Mann, W. A. (Inventor)

    1979-01-01

    A relatively simple, compact artificial hand, is described which includes hooks pivotally mounted on first frame to move together and apart. The first frame is rotatably mounted on a second frame to enable "turning at the wrist" movement without limitation. The second frame is pivotally mounted on a third frame to permit 'flexing at the wrist' movement. A hook-driving motor is fixed to the second frame but has a shaft that drives a speed reducer on the first frame which, in turn, drives the hooks. A second motor mounted on the second frame, turns a gear on the first frame to rotate the first frame and the hooks thereon. A third motor mounted on the third frame, turns a gear on a second frame to pivot it.

  12. The Coude spectrograph and echelle scanner of the 2.7 m telescope at McDonald observatory

    NASA Technical Reports Server (NTRS)

    Tull, R. G.

    1972-01-01

    The design of the Coude spectrograph of the 2.7 m McDonald telescope is discussed. A description is given of the Coude scanner which uses the spectrograph optics, the configuration of the large echelle and the computer scanner control and data systems.

  13. Effect of Acoustic Spectrographic Instruction on Production of English /i/ and /I/ by Spanish Pre-Service English Teachers

    ERIC Educational Resources Information Center

    Quintana-Lara, Marcela

    2014-01-01

    This study investigates the effects of Acoustic Spectrographic Instruction on the production of the English phonological contrast /i/ and / I /. Acoustic Spectrographic Instruction is based on the assumption that physical representations of speech sounds and spectrography allow learners to objectively see and modify those non-accurate features in…

  14. Effect of Training Japanese L1 Speakers in the Production of American English /r/ Using Spectrographic Visual Feedback

    ERIC Educational Resources Information Center

    Patten, Iomi; Edmonds, Lisa A.

    2015-01-01

    The present study examines the effects of training native Japanese speakers in the production of American /r/ using spectrographic visual feedback. Within a modified single-subject design, two native Japanese participants produced single words containing /r/ in a variety of positions while viewing live spectrographic feedback with the aim of…

  15. Compaction-based VLSI layout

    SciTech Connect

    Xiong, Xiao-Ming.

    1989-01-01

    Generally speaking, a compaction based VLSI layout system consists of two major parts: (1) a symbolic editor which maintains explicit connectivity and structural information about the circuit; (2) a compactor which translates the high level description of a circuit to the detailed layout needed for fabrication and tries to make as compact a layout as Possible without violating any design rules. Instead of developing a complete compaction based VLSI layout system, this thesis presents some theoretical concepts and several new compaction techniques, such as scan line based approach, which can either cooperate with a symbolic editor to form a layout system or work as a post-process step to improve the results obtained by an existing layout system. Also, some compaction related problems are solved and proposed. Based on the special property of channel routing, the author presents a geometric method for channel compaction. For a given channel routing topology, the minimum channel height is always achieved with the incorporation of sliding contacts and automatically inserting necessary jogs. The geometric compaction approach is then generalized and applied to compact the entire VLSI chip at the building-block level. With a systematic way of automatic jog insertion, he proves that under the given layout topology and design rules, the lower bound of one dimensional compaction with automatic jog insertion is achieved by the geometric compaction algorithm. A new simultaneous two-dimensional compaction algorithm is developed primarily for placement refinement of building-block layout. The algorithm is based on a set of defined graph operations on a mixed adjacency graph for a given placement. The mixed-adjacency graph can be updated efficiently if the placement is represented by tiles in the geometric domain.

  16. Most Efficient Spectrograph to Shoot the Southern Skies

    NASA Astrophysics Data System (ADS)

    2009-05-01

    -shooter, for a total of 350 observing nights, making it the second most requested instrument at the Very Large Telescope in this period. More information ESO's Very Large Telescope (VLT) is the world's most advanced optical instrument. It is an ensemble of four 8.2-metre telescopes located at the Paranal Observatory on an isolated mountain peak in the Atacama Desert in North Chile. The four 8.2-metre telescopes have a total of 12 focal stations where different instruments for imaging and spectroscopic observations are installed and a special station where the light of the four telescopes is combined for interferometric observations. The first VLT instrument was installed in 1998 and has been followed by 12 more in the last 10 years, distributed at the different focal stations. X-shooter is the first of the second generation of VLT instruments and replaces the workhorse-instrument FORS1, which has been successfully used for more than ten years by hundreds of astronomers. X-shooter operates at the Cassegrain focus of the Kueyen telescope (UT2). In response to an ESO Call for Proposals for second generation VLT instrumentation, ESO received three proposals for an intermediate resolution, high efficiency spectrograph. These were eventually merged into a single proposal around the present concept of X-shooter, which was approved for construction in November 2003. The Final Design Review, at which the instrument design is finalised and declared ready for construction, took place in April 2006. The first observations with the instrument at the telescope in its full configuration were on 14 March 2009. X-shooter is a joint project by Denmark, France, Italy, the Netherlands and ESO. The collaborating institutes in Denmark are the Niels Bohr and the DARK Institutes of the University of Copenhagen and the National Space Institute (Technical University of Denmark); in France GEPI at the Observatoire de Paris and APC at the Université D. Diderot, with contributions from the CEA and the

  17. A dual-channel, focusing x-ray spectrograph with uniform dispersion for Z pinch plasmas measurement

    SciTech Connect

    Yang Qingguo; Li Zeren; Chen Guanhua; Ye Yan; Huang Xianbin; Cai Hongchun; Li Jing; Xiao Shali

    2012-01-15

    A dual-channel, focusing x-ray spectrograph with uniform dispersion (i.e., the linear dispersion of this spectrograph is a constant) is described for measuring the x-ray spectra emission from the hot, dense Al Z pinch plasmas. The spectrograph uses double uniform-dispersed crystals (e.g., a Quartz 1010 crystal and a Mica 002 crystal) as dispersion elements and a double-film box as detector to achieve the simultaneous recording of the time integrated spectrum covering a wide spectral range of {approx}5-9 A. Since this spectrograph disperse the x-rays on the detector plane with uniform spacing for every wavelength, it needs not the calibration of the wavelength with spatial coordinate, thereby own the advantages of easiness and veracity for spectra identification. The design of this spectrograph and the example of experiment on the ''Yang'' accelerator are presented.

  18. LRS2: a new low-resolution spectrograph for the Hobby-Eberly Telescope

    NASA Astrophysics Data System (ADS)

    Lee, Hanshin; Chonis, Taylor S.; Hill, Gary J.; DePoy, Darren L.; Marshall, Jennifer L.; Vattiat, Brian

    2010-07-01

    In the era of the Hobby-Eberly Telescope (HET) Wide-Field Upgrade (WFU), the current Low-Resolution Spectrograph (LRS) will be replaced with a more capable red-optimized fiber instrument, called LRS2. This new spectrograph will be based on the Visible Integral-field Replicable Unit Spectrograph (VIRUS) that was designed to be easily adapted to a wide range of spectral resolutions, and wavelength ranges. The current snapshot of LRS2, fed by a 7x12 sq. arcsec fiber integral-field unit (IFU), covers 350-1100 nm, simultaneously at a fixed resolving power R~1800, with the wavelength range split into two pairs of spectrographs, one for the blue to red wavelength range (350-630 nm) and the other for the red and far-red range (630-1100 nm). These units are designated LRS2-B and LRS2-R, respectively. Only minimal modification from the base VIRUS design in gratings (for both pairs) and in the detector (for the red pair only) is required. In addition to this flexibility, the generic nature and massively replicable characteristic of the instrument can allow us to adapt the instrument to a wide range of not only telescope diameters (1 m ~ 40 m), but also observing modes (single to multiple objects). We discuss the current snapshot of the LRS2 design.

  19. Spectrographic date on cores from the Pacific Ocean and the Gulf of Mexico

    USGS Publications Warehouse

    Young, E.J.

    1968-01-01

    Average quantitative spectrographic data are presented for V, Ti, Zr, Ni, Co, Sc, Cr and La in the following Pacific deep-sea cores: siliceous ooze (3), red clay (6), volcanic mud (3), calcareous ooze (3) and one manganese nodule, and in 23 near-shore cores, mostly from the Gulf of Mexico. ?? 1968.

  20. A spectrograph for exoplanet observations calibrated at the centimetre-per-second level.

    PubMed

    Wilken, Tobias; Curto, Gaspare Lo; Probst, Rafael A; Steinmetz, Tilo; Manescau, Antonio; Pasquini, Luca; González Hernández, Jonay I; Rebolo, Rafael; Hänsch, Theodor W; Udem, Thomas; Holzwarth, Ronald

    2012-05-31

    The best spectrographs are limited in stability by their calibration light source. Laser frequency combs are the ideal calibrators for astronomical spectrographs. They emit a spectrum of lines that are equally spaced in frequency and that are as accurate and stable as the atomic clock relative to which the comb is stabilized. Absolute calibration provides the radial velocity of an astronomical object relative to the observer (on Earth). For the detection of Earth-mass exoplanets in Earth-like orbits around solar-type stars, or of cosmic acceleration, the observable is a tiny velocity change of less than 10 cm s(-1), where the repeatability of the calibration--the variation in stability across observations--is important. Hitherto, only laboratory systems or spectrograph calibrations of limited performance have been demonstrated. Here we report the calibration of an astronomical spectrograph with a short-term Doppler shift repeatability of 2.5 cm s(-1), and use it to monitor the star HD 75289 and recompute the orbit of its planet. This repeatability should make it possible to detect Earth-like planets in the habitable zone of star or even to measure the cosmic acceleration directly.

  1. An optical spectrograph design for a new-generation multiple object Doppler instrument

    NASA Astrophysics Data System (ADS)

    Zhao, Bo; Ge, Jian

    2006-06-01

    This paper describes an optical spectrograph design for the W.M. Keck Exoplanet Tracker (ET) multi-object Doppler radial velocity instrument. The Keck ET is currently installed at the Sloan 2.5m telescope (Ge et al. this proceedings), and is capable of simultaneously monitoring 60 stars with high precision for a planet survey. The spectrograph consists of an entrance slit, collimator optics, a Volume Phase Holographic (VPH) grating, camera optics and a 4kx4k CCD camera, and provides a spectral resolution of R =5000, with a 180 mm diameter collimated beam. The collimator and camera optics (300 mm largest diameter) are made of two standard optical grade glasses: BK7 and F2, respectively. The spectrograph is transmissive and optimized for delivering high throughput and high image quality over the entire operation bandwidth: 500-590 nm. The f/4 input beams from the Keck ET interferometer are converted to f/1.5 beams on the detector by this spectrograph, and form 60 stellar fringe spectra.

  2. Theory and computation of three cosmic origin spectrograph aspheric gratings recorded with a multimode deformable mirror.

    PubMed

    Duban, M

    1999-03-01

    The theory of three Cosmic Origin Spectrograph holographic gratings recorded with a deformable plane mirror is presented. Their working conditions are severe, since they have to correct the strong spherical aberration and the field astigmatism of the Hubble Space Telescope. Recorded on aspherized substrates, the gratings produce images that are diffraction limited with regard to spectral resolution. PMID:18305717

  3. A spectrograph for exoplanet observations calibrated at the centimetre-per-second level.

    PubMed

    Wilken, Tobias; Curto, Gaspare Lo; Probst, Rafael A; Steinmetz, Tilo; Manescau, Antonio; Pasquini, Luca; González Hernández, Jonay I; Rebolo, Rafael; Hänsch, Theodor W; Udem, Thomas; Holzwarth, Ronald

    2012-05-31

    The best spectrographs are limited in stability by their calibration light source. Laser frequency combs are the ideal calibrators for astronomical spectrographs. They emit a spectrum of lines that are equally spaced in frequency and that are as accurate and stable as the atomic clock relative to which the comb is stabilized. Absolute calibration provides the radial velocity of an astronomical object relative to the observer (on Earth). For the detection of Earth-mass exoplanets in Earth-like orbits around solar-type stars, or of cosmic acceleration, the observable is a tiny velocity change of less than 10 cm s(-1), where the repeatability of the calibration--the variation in stability across observations--is important. Hitherto, only laboratory systems or spectrograph calibrations of limited performance have been demonstrated. Here we report the calibration of an astronomical spectrograph with a short-term Doppler shift repeatability of 2.5 cm s(-1), and use it to monitor the star HD 75289 and recompute the orbit of its planet. This repeatability should make it possible to detect Earth-like planets in the habitable zone of star or even to measure the cosmic acceleration directly. PMID:22660320

  4. Compost improves compacted urban soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Urban construction sites usually result in compacted soils that limit infiltration and root growth. The purpose of this study was to determine if compost, aeration, and/or prairie grasses can remediate a site setup as a simulated post-construction site (compacted). Five years after establishing the ...

  5. The Meaning of a Compact

    ERIC Educational Resources Information Center

    Wasescha, Anna

    2016-01-01

    To mark the 30th anniversary of "Campus Compact," leaders from across the network came together in the summer of 2015 to reaffirm a shared commitment to the public purposes of higher education. Campus Compact's 30th Anniversary Action Statement of Presidents and Chancellors is the product of that collective endeavor. In signing the…

  6. LRS2: the new facility low resolution integral field spectrograph for the Hobby-Eberly telescope

    NASA Astrophysics Data System (ADS)

    Chonis, Taylor S.; Hill, Gary J.; Lee, Hanshin; Tuttle, Sarah E.; Vattiat, Brian L.

    2014-07-01

    The second generation Low Resolution Spectrograph (LRS2) is a new facility instrument for the Hobby-Eberly Telescope (HET). Based on the design of the Visible Integral-field Replicable Unit Spectrograph (VIRUS), which is the new flagship instrument for carrying out the HET Dark Energy Experiment (HETDEX), LRS2 provides integral field spectroscopy for a seeing-limited field of 12" x 6". For LRS2, the replicable design of VIRUS has been leveraged to gain broad wavelength coverage from 370 nm to 1.0 μm, spread between two fiber-fed dual- channel spectrographs, each of which can operate as an independent instrument. The blue spectrograph, LRS2-B, covers 370 λ (nm) <= 470 and 460 <= λ (nm) <= 700 at fixed resolving powers of R = λ/δλ ≍ 1900 and 1100, respectively, while the red spectrograph, LRS2-R, covers 650 <= λ (nm) <= 842 and 818 <= λ (nm) <= 1050 with both of its channels having R ≍ 1800. In this paper, we present a detailed description of the instrument's design in which we focus on the departures from the basic VIRUS framework. The primary modifications include the fore-optics that are used to feed the fiber integral field units at unity fill-factor, the cameras' correcting optics and detectors, and the volume phase holographic grisms. We also present a model of the instrument's sensitivity and a description of specific science cases that have driven the design of LRS2, including systematically studying the spatially resolved properties of extended Lyα blobs at 2 < z < 3. LRS2 will provide a powerful spectroscopic follow-up platform for large surveys such as HETDEX.

  7. Subsystem Imaging Performance and Modeling of the Infrared Multi-Object Spectrograph

    NASA Technical Reports Server (NTRS)

    Connelly, Joseph A.; Tveekrem, June L.; Ohl, Raymond G.; Mink, Ronald; Chambers, V. John; Mentzell, J. Eric; Greenhouse, Matthew A.; MacKenty, John W.; Krebs, Carolyn (Technical Monitor)

    2002-01-01

    The Infrared Multi-Object Spectrograph (IRMOS) is a facility instrument for the Kitt Peak National Observatory Mayall Telescope (3.8 meter). IRMOS is a near-IR (0.8 - 2.5 micron) spectrograph with low to mid resolution (R=lambda/delta, lambda = 300 - 3800). The IRMOS spectrograph produces simultaneous spectra of - 100 objects in its 2.8 x 2.0 arc-min field of view using a commercial MEMS multi-mirror array device (MMA). The IRMOS optical design consists of two imaging systems, or "stages." The focal reducer, stage one, images the focal plane of the telescope onto the MMA. The spectrograph, stage two, images the MMA onto the detector. We describe the breadboard alignment method and imaging and scattered light performance for both the focal reducer and spectrograph. This testing provides verification of the optomechanical alignment method, and a measurement of the contribution of scattered light in the system due to mirror small scale surface error. After the stage I and 2 optics are integrated with the instrument, our test results will make it possible to distinguish between scattered light from the mirrors and the MMA. Image testing will be done at four wavelengths in the visible and near-IR. A mercury-argon pencil lamp will provide spectral lines at 546.1 and 1012 nm, and a blackbody radiation source lines at 1600 and 2200 nm. A CCD camera will be used as a detector for the visible wavelengths, and an IR photodiode will be used for the IR wavelengths. We compare our data with a theoretical analysis using a commercial software package. Mirror surface error is modeled by treating each surface as a superposition of various gratings (e.g., diamond turning tool marks, features due to the impurities of Al 6061, and periodic mid-frequency errors due to drift during machining).

  8. Compact vacuum insulation

    DOEpatents

    Benson, D.K.; Potter, T.F.

    1992-10-27

    Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

  9. Compact vacuum insulation

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1992-01-01

    Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases therebetween are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and variious laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels.

  10. A compact acoustic recorder

    NASA Astrophysics Data System (ADS)

    Stein, Ronald

    1989-09-01

    The design and operation of a portable compact acoustic recorder is discussed. Designed to be used in arctic conditions for applications that require portable equipment, the device is configured to fit into a lightweight briefcase. It will operate for eight hours at -40 F with heat provided by a hot water bottle. It has proven to be an effective scientific tool in the measurement of underwater acoustic signals in arctic experiments. It has also been used successfully in warmer climates, e.g., in recording acoustic signals from small boats with no ac power. The acoustic recorder's cost is moderate since it is based on a Sony Walkman Professional (WM-D6C) tape recorder playback unit. A speaker and battery assembly and a hydrophone interface electronic assembly complete the system electronics. The interface assembly supplies a number of functions, including a calibration tone generator, an audio amplifier, and a hydrophone interface. Calibrated acoustic recordings can be made by comparing the calibration tone amplitude with the acoustic signal amplitude. The distortion of the recording is minimized by using a high quality, consumer tape recorder.

  11. Compact plasma accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E. (Inventor)

    2004-01-01

    A compact plasma accelerator having components including a cathode electron source, an anodic ionizing gas source, and a magnetic field that is cusped. The components are held by an electrically insulating body having a central axis, a top axial end, and a bottom axial end. The cusped magnetic field is formed by a cylindrical magnet having an axis of rotation that is the same as the axis of rotation of the insulating body, and magnetized with opposite poles at its two axial ends; and an annular magnet coaxially surrounding the cylindrical magnet, magnetized with opposite poles at its two axial ends such that a top axial end has a magnetic polarity that is opposite to the magnetic polarity of a top axial end of the cylindrical magnet. The ionizing gas source is a tubular plenum that has been curved into a substantially annular shape, positioned above the top axial end of the annular magnet such that the plenum is centered in a ring-shaped cusp of the magnetic field generated by the magnets. The plenum has one or more capillary-like orifices spaced around its top such that an ionizing gas supplied through the plenum is sprayed through the one or more orifices. The plenum is electrically conductive and is positively charged relative to the cathode electron source such that the plenum functions as the anode; and the cathode is positioned above and radially outward relative to the plenum.

  12. Compact neutron generator

    DOEpatents

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  13. Compact Dexterous Robotic Hand

    NASA Technical Reports Server (NTRS)

    Lovchik, Christopher Scott (Inventor); Diftler, Myron A. (Inventor)

    2001-01-01

    A compact robotic hand includes a palm housing, a wrist section, and a forearm section. The palm housing supports a plurality of fingers and one or more movable palm members that cooperate with the fingers to grasp and/or release an object. Each flexible finger comprises a plurality of hingedly connected segments, including a proximal segment pivotally connected to the palm housing. The proximal finger segment includes at least one groove defining first and second cam surfaces for engagement with a cable. A plurality of lead screw assemblies each carried by the palm housing are supplied with power from a flexible shaft rotated by an actuator and output linear motion to a cable move a finger. The cable is secured within a respective groove and enables each finger to move between an opened and closed position. A decoupling assembly pivotally connected to a proximal finger segment enables a cable connected thereto to control movement of an intermediate and distal finger segment independent of movement of the proximal finger segment. The dexterous robotic hand closely resembles the function of a human hand yet is light weight and capable of grasping both heavy and light objects with a high degree of precision.

  14. Compaction managed mirror bend achromat

    DOEpatents

    Douglas, David

    2005-10-18

    A method for controlling the momentum compaction in a beam of charged particles. The method includes a compaction-managed mirror bend achromat (CMMBA) that provides a beamline design that retains the large momentum acceptance of a conventional mirror bend achromat. The CMMBA also provides the ability to tailor the system momentum compaction spectrum as desired for specific applications. The CMMBA enables magnetostatic management of the longitudinal phase space in Energy Recovery Linacs (ERLs) thereby alleviating the need for harmonic linearization of the RF waveform.

  15. Stray-light contamination and spatial deconvolution of slit-spectrograph observations

    NASA Astrophysics Data System (ADS)

    Beck, C.; Rezaei, R.; Fabbian, D.

    2011-11-01

    Context. Stray light caused by scattering on optical surfaces and in the Earth's atmosphere degrades the spatial resolution of observations. Whereas post-facto reconstruction techniques are common for 2D imaging and spectroscopy, similar options for slit-spectrograph data are rarely applied. Aims: We study the contribution of stray light to the two channels of the POlarimetric LIttrow Spectrograph (POLIS) at 396 nm and 630 nm as an example of a slit-spectrograph instrument. We test the performance of different methods of stray-light correction and spatial deconvolution to improve the spatial resolution post-facto. Methods: We model the stray light as having two components: a spectrally dispersed component and a "parasitic" component of spectrally undispersed light caused by scattering inside the spectrograph. We used several measurements to estimate the two contributions: a) observations with a (partly) blocked field of view (FOV); b) a convolution of the FTS spectral atlas; c) imaging of the spider mounting in the pupil plane; d) umbral profiles; and e) spurious polarization signal in telluric spectral lines. The measurements with a partly blocked FOV in the focal plane allowed us to estimate the spatial point spread function (PSF) of POLIS and the main spectrograph of the German Vacuum Tower Telescope (VTT). We then used the obtained PSF for a deconvolution of both spectroscopic and spectropolarimetric data and investigated the effect on the spectra. Results: The parasitic contribution can be directly and accurately determined for POLIS, amounting to about 5% (0.3%) of the (continuum) intensity at 396 nm (630 nm). The spectrally dispersed stray light is less accessible because of its many contributing sources. We estimate a lower limit of about 10% across the full FOV for the dispersed stray light from umbral profiles. In quiet Sun regions, the stray-light level from the close surroundings (d < 2'') of a given spatial point is about 20%. The stray light reduces

  16. Compact Grism Spectrometer

    NASA Astrophysics Data System (ADS)

    Teare, S. W.

    2003-05-01

    Many observatories and instrument builders are retrofitting visible and near-infrared spectrometers into their existing imaging cameras. Camera designs that reimage the focal plane and have the optical filters located in a pseudo collimated beam are ideal candidates for the addition of a spectrometer. One device commonly used as the dispersing element for such spectrometers is a grism. The traditional grism is constructed from a prism that has had a diffraction grating applied on one surface. The objective of such a design is to use the prism wedge angle to select the desired "in-line" or "zero-deviation" wavelength that passes through on axis. The grating on the surface of the prism provides much of the dispersion for the spectrometer. A grism can also be used in a "constant-dispersion" design which provides an almost linear spatial scale across the spectrum. In this paper we provide an overview of the development of a grism spectrometer for use in a near infrared camera and demonstrate that a compact grism spectrometer can be developed on a very modest budget that can be afforded at almost any facility. The grism design was prototyped using visible light and then a final device was constructed which provides partial coverage in the near infrared I, J, H and K astronomical bands using the appropriate band pass filter for order sorting. The near infrared grism presented here provides a spectral resolution of about 650 and velocity resolution of about 450 km/s. The design of this grism relied on a computer code called Xspect, developed by the author, to determine the various critical parameters of the grism. This work was supported by a small equipment grant from NASA and administered by the AAS.

  17. Compact Holographic Data Storage

    NASA Astrophysics Data System (ADS)

    Chao, T. H.; Reyes, G. F.; Zhou, H.

    2001-01-01

    NASA's future missions would require massive high-speed onboard data storage capability to Space Science missions. For Space Science, such as the Europa Lander mission, the onboard data storage requirements would be focused on maximizing the spacecraft's ability to survive fault conditions (i.e., no loss in stored science data when spacecraft enters the 'safe mode') and autonomously recover from them during NASA's long-life and deep space missions. This would require the development of non-volatile memory. In order to survive in the stringent environment during space exploration missions, onboard memory requirements would also include: (1) survive a high radiation environment (1 Mrad), (2) operate effectively and efficiently for a very long time (10 years), and (3) sustain at least a billion write cycles. Therefore, memory technologies requirements of NASA's Earth Science and Space Science missions are large capacity, non-volatility, high-transfer rate, high radiation resistance, high storage density, and high power efficiency. JPL, under current sponsorship from NASA Space Science and Earth Science Programs, is developing a high-density, nonvolatile and rad-hard Compact Holographic Data Storage (CHDS) system to enable large-capacity, high-speed, low power consumption, and read/write of data in a space environment. The entire read/write operation will be controlled with electrooptic mechanism without any moving parts. This CHDS will consist of laser diodes, photorefractive crystal, spatial light modulator, photodetector array, and I/O electronic interface. In operation, pages of information would be recorded and retrieved with random access and high-speed. The nonvolatile, rad-hard characteristics of the holographic memory will provide a revolutionary memory technology meeting the high radiation challenge facing the Europa Lander mission. Additional information is contained in the original extended abstract.

  18. Compact, Reliable EEPROM Controller

    NASA Technical Reports Server (NTRS)

    Katz, Richard; Kleyner, Igor

    2010-01-01

    A compact, reliable controller for an electrically erasable, programmable read-only memory (EEPROM) has been developed specifically for a space-flight application. The design may be adaptable to other applications in which there are requirements for reliability in general and, in particular, for prevention of inadvertent writing of data in EEPROM cells. Inadvertent writes pose risks of loss of reliability in the original space-flight application and could pose such risks in other applications. Prior EEPROM controllers are large and complex and do not provide all reasonable protections (in many cases, few or no protections) against inadvertent writes. In contrast, the present controller provides several layers of protection against inadvertent writes. The controller also incorporates a write-time monitor, enabling determination of trends in the performance of an EEPROM through all phases of testing. The controller has been designed as an integral subsystem of a system that includes not only the controller and the controlled EEPROM aboard a spacecraft but also computers in a ground control station, relatively simple onboard support circuitry, and an onboard communication subsystem that utilizes the MIL-STD-1553B protocol. (MIL-STD-1553B is a military standard that encompasses a method of communication and electrical-interface requirements for digital electronic subsystems connected to a data bus. MIL-STD- 1553B is commonly used in defense and space applications.) The intent was to both maximize reliability while minimizing the size and complexity of onboard circuitry. In operation, control of the EEPROM is effected via the ground computers, the MIL-STD-1553B communication subsystem, and the onboard support circuitry, all of which, in combination, provide the multiple layers of protection against inadvertent writes. There is no controller software, unlike in many prior EEPROM controllers; software can be a major contributor to unreliability, particularly in fault

  19. Module-type flat-field grazing-incidence spectrographs for large Tokamak (JT-60) plasma diagnosis

    NASA Astrophysics Data System (ADS)

    Nagata, Hiroshi; Kihara, Naoto; Yamashita, Takaji; Sugie, Tatsuo; Kubo, Hirotaka; Shiho, Makoto

    1990-09-01

    Module-type flat-field grazing-incidence spectrographs with holographic gratings and multichannel detectors for large TOKAMAK (JT-60) plasma diagnosis are developed. The spectrographs cover the different wavelength regions from 0.5-122 nm, and are set to measure impurity lines in the plasma every 20 ms with space resolution of 7 cm. The flat-field imaging properties with designed wavelength resolution were confirmed, and results of tokamak plasma measurements proved the value of these spectrographs for plasma diagnosis.

  20. What Is Business's Social Compact?

    ERIC Educational Resources Information Center

    Avishai, Bernard

    1994-01-01

    Under the "new" social compact, businesses must focus on continuous learning and thus have both an obligation to support teaching and an opportunity to profit from it. Learning organizations must also be teaching organizations. (SK)

  1. A Compact Beam Measurement Setup

    NASA Astrophysics Data System (ADS)

    Graf, Urs U.

    2016-08-01

    We present the design of a compact measurement device to determine the position of a beam in a radio optical setup. The unit is used to align the Terahertz optics of the GREAT instrument on the airborne astronomical observatory SOFIA.

  2. MESOSCALE SIMULATIONS OF POWDER COMPACTION

    SciTech Connect

    Lomov, Ilya; Fujino, Don; Antoun, Tarabay; Liu, Benjamin

    2009-12-28

    Mesoscale 3D simulations of shock compaction of metal and ceramic powders have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating a well-characterized shock compaction experiment of a porous ductile metal. Simulation results using the Steinberg material model and handbook values for solid 2024 aluminum showed good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not as well studied as metals, so a simple material model for solid ceramic (tungsten carbide) has been calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powders have been performed and showed good agreement with experimental data. The numerical shock wave profile has same character and thickness as that measured experimentally using VISAR. The numerical results show reshock states above the single-shock Hugoniot line as observed in experiments. We found that for good quantitative agreement with experiments 3D simulations are essential.

  3. Mesoscale Simulations of Powder Compaction

    NASA Astrophysics Data System (ADS)

    Lomov, Ilya.; Fujino, Don; Antoun, Tarabay; Liu, Benjamin

    2009-12-01

    Mesoscale 3D simulations of shock compaction of metal and ceramic powders have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating a well-characterized shock compaction experiment of a porous ductile metal. Simulation results using the Steinberg material model and handbook values for solid 2024 aluminum showed good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not as well studied as metals, so a simple material model for solid ceramic (tungsten carbide) has been calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powders have been performed and showed good agreement with experimental data. The numerical shock wave profile has same character and thickness as that measured experimentally using VISAR. The numerical results show reshock states above the single-shock Hugoniot line as observed in experiments. We found that for good quantitative agreement with experiments 3D simulations are essential.

  4. An isolated compact galaxy triplet

    NASA Astrophysics Data System (ADS)

    Feng, Shuai; Shao, Zheng-Yi; Shen, Shi-Yin; Argudo-Fernández, Maria; Wu, Hong; Lam, Man-I.; Yang, Ming; Yuan, Fang-Ting

    2016-05-01

    We report the discovery of an isolated compact galaxy triplet SDSS J084843.45+164417.3, which is first detected by the LAMOST spectral survey and then confirmed by a spectroscopic observation of the BFOSC mounted on the 2.16 meter telescope located at Xinglong Station, which is administered by National Astronomical Observatories, Chinese Academy of Sciences. It is found that this triplet is an isolated and extremely compact system, which has an aligned configuration and very small radial velocity dispersion. The member galaxies have similar colors and show marginal star formation activities. These results support the opinion that the compact triplets are well-evolved systems rather than hierarchically forming structures. This serendipitous discovery reveals the limitations of fiber spectral redshift surveys in studying such a compact system, and demonstrates the necessity of additional observations to complete the current redshift sample.

  5. Compact Ho:YLF Laser

    NASA Technical Reports Server (NTRS)

    Hemmati, H.

    1988-01-01

    Longitudinal pumping by laser diodes increases efficiency. Improved holmium:yttrium lithium fluoride laser radiates as much as 56 mW of power at wavelength of 2.1 micrometer. New Ho:YLF laser more compact and efficient than older, more powerful devices of this type. Compact, efficient Ho:YLF laser based on recent successes in use of diode lasers to pump other types of solid-state lasers.

  6. Detectors for the James Webb Space Telescope Near-Infrared Spectrograph

    NASA Technical Reports Server (NTRS)

    Rauscher, Bernard J.; Figer, Donald F.; Regan, Michael W.; Boeker, Torsten; Garnett, James; Hill, Robert J.; Bagnasco, Georgio; Balleza, Jesus; Barney, Richard; Bergeron, Louis E.

    2004-01-01

    The Near-Infrared Spectrograph (NIRSpec) is the James Webb Space Telescope's primary near-infrared spectrograph. NASA is providing the NIRSpec detector subsystem, which consists of the focal plane array, focal plane electronics, cable harnesses, and software. The focal plane array comprises two closely-butted lambda (sub co) approximately 5 micrometer Rockwell HAWAII- 2RG sensor chip assemblies. After briefly describing the NIRSpec instrument, we summarize some of the driving requirements for the detector subsystem, discuss the baseline architecture (and alternatives), and presents some recent detector test results including a description of a newly identified noise component that we have found in some archival JWST test data. We dub this new noise component, which appears to be similar to classical two-state popcorn noise in many aspects, "popcorn mesa noise." We close with the current status of the detector subsystem development effort.

  7. Flat-fielding strategy for the JWST/NIRSpec multi-object spectrograph

    NASA Astrophysics Data System (ADS)

    Rawle, T. D.; Alves de Oliveira, C.; Birkmann, S. M.; Boeker, T.; de Marchi, G.; Ferruit, P.; Giardino, G.; Luetzgendorf, N.; Sirianni, M.

    2016-07-01

    The Near-Infrared Spectrograph (NIRSpec) onboard the James Webb Space Telescope (JWST) will be the first space-borne Multi-Object Spectrograph (MOS), comprising a quarter of a million individually addressable microshutters to allow simultaneous observation of ˜100 targets. We present the strategy for flat-fielding the NIRSpec MOS, correcting for the combined effects of the telescope and instrument throughput as well as the detector response. With a highly configurable shutter array, a novel approach is required to ensure that flat- field reference observations do not significantly impact telescope efficiency. We envisage a two-step strategy: 1) Creation of a three-dimensional master flat-field reference (two spatial dimensions, one wavelength) from a small set of well-designed calibration data; 2) Correction of any data frame using a two-dimensional flat-field generated on-the-fly, for that specific MOS configuration, from the master.

  8. PUCHEROS: a low-cost fiber-fed Echelle Spectrograph for the visible spectral range

    NASA Astrophysics Data System (ADS)

    Vanzi, Leonardo; Chacon, Juan A.; Baffico, Maurizio; Avila, Gerardo; Guirao, Carlos; Rivinius, Thomas; Stefl, Stan; Baade, Dietrich

    2010-07-01

    PUCHEROS is a high resolution optical Echelle spectrograph designed for the 50 cm telescope located at the Pontificia Universidad Católica de Chile (PUC) observatory of Santa Martina. With a resolution about 20,000, PUCHEROS is an ideal instrument to study bright and variable objects, our driving science case is the study of bright early type stars. Using a fiber optic to bring the light from the telescope to the instrument, it can be located in a gravity invariant, temperature stabilized location, allowing precise long-term stability. PUCHEROS will be a valuable tool both for research and didactics at the graduate and undergraduate level. In this work we present the optical and mechanical design of the spectrograph as well as the first laboratory tests.

  9. X-shooter-backbone and UV-blue and visible spectrographs: final AIV and measured performances

    NASA Astrophysics Data System (ADS)

    Rasmussen, Per Kjærgaard; Zerbi, Filippo M.; Dekker, Hans; Vernet, Joel; Andersen, Jeppe J.; De Caprio, Vincenzo; Dimarcantonio, Paolo; D'Odorico, Sandro; Lizon, Jean-Louis; Lucuix, Christian; Michaelsen, Niels; Molinari, Emilio; Nørregaard, Preben; Riva, Alberto; Riva, Marco; Santin, Paolo; Sørensen, Anton N.; Spanò, Paolo; Wistisen, Dennis

    2008-07-01

    X-shooter is a wide band (U to K) intermediate resolution (4000-14000) single object three-arms spectrograph for the VLT. Currently in the last phase of integration, X-shooter will see the first light at ESO Paranal as the first of the VLT second generation instruments in the last quarter of 2008. We describe in this paper the final steps in the integration and testing phase of the central Backbone with its key functions (including the active flexure compensation mirrors) and of the two UV-Blue and Visible spectroscopic arms. We report on the stability results of the preslit optics and of the spectrographs and on the remarkable efficiency which is derived from the measurements of the optical components of the instrument.

  10. Rocket studies of solar corona and transition region. [X-Ray spectrometer/spectrograph telescope

    NASA Technical Reports Server (NTRS)

    Acton, L. W.; Bruner, E. C., Jr.; Brown, W. A.; Nobles, R. A.

    1979-01-01

    The XSST (X-Ray Spectrometer/Spectrograph Telescope) rocket payload launched by a Nike Boosted Black Brant was designed to provide high spectral resolution coronal soft X-ray line information on a spectrographic plate, as well as time resolved photo-electric records of pre-selected lines and spectral regions. This spectral data is obtained from a 1 x 10 arc second solar region defined by the paraboloidal telescope of the XSST. The transition region camera provided full disc images in selected spectral intervals originating in lower temperature zones than the emitting regions accessible to the XSST. A H-alpha camera system allowed referencing the measurements to the chromospheric temperatures and altitudes. Payload flight and recovery information is provided along with X-ray photoelectric and UV flight data, transition camera results and a summary of the anomalies encountered. Instrument mechanical stability and spectrometer pointing direction are also examined.

  11. VIRUS-W: an integral field unit spectrograph dedicated to the study of spiral galaxy bulges

    NASA Astrophysics Data System (ADS)

    Fabricius, Maximilian H.; Barnes, Stuart; Bender, Ralf; Drory, Niv; Grupp, Frank; Hill, Gary J.; Hopp, Ulrich; MacQueen, Phillip J.

    2008-07-01

    We present the design, layout and performance estimates for a fiber based Integral Field Unit spectrograph. This instrument is built for flexible use at different telescopes, and in particular for the new 2m telescope on Mount Wendelstein in the Bavarian Alps. Based on the VIRUS spectrograph for the HETDEX experiment, the proposed instrument will have a fiber head consisting of 267 optical fibers. The large angular field of view of 150×75 arcseconds will allow full coverage of the bulge regions of most local late type galaxies in one or two pointings. Realized by the usage of VPH gratings, a R ~ 2500 and a R ~ 6800 mode with 850Å and 515Å wavelength coverage will be dedicated to the study of stellar populations and kinematics of late type galaxy bulges.

  12. EAGLE ISS: a modular twin-channel integral-field near-IR spectrograph

    NASA Astrophysics Data System (ADS)

    Hastings, Peter; Stobie, Brian; Vivès, Sébastien; Vola, Pascal; Wells, Martyn; Evans, Christopher

    2010-07-01

    The ISS (Integral-field Spectrograph System) has been designed as part of the EAGLE Phase A Instrument Study for the E-ELT. It consists of two input channels of 1.65x1.65 arcsec field-of-view, each reconfigured spatially by an imageslicing integral-field unit to feed a single near-IR spectrograph using cryogenic volume-phase-holographic gratings to disperse the image spectrally. A 4k x 4k array detector array records the dispersed images. The optical design employs anamorphic magnification, image slicing, VPH gratings scanned with a novel cryo-mechanism and a three-lens camera. The mechanical implementation features IFU optics in Zerodur, a modular bench structure and a number of highprecision cryo-mechanisms.

  13. First starlight spectrum captured using an integrated photonic micro-spectrograph

    NASA Astrophysics Data System (ADS)

    Cvetojevic, N.; Jovanovic, N.; Betters, C.; Lawrence, J. S.; Ellis, S. C.; Robertson, G.; Bland-Hawthorn, J.

    2012-08-01

    Photonic technologies have received growing consideration for incorporation into next-generation astronomical instrumentation, owing to their miniature footprint and inherent robustness. In this paper we present results from the first on-telescope demonstration of a miniature photonic spectrograph for astronomy, by obtaining spectra spanning the entire H-band from several stellar targets. The prototype was tested on the 3.9 m Anglo-Australian telescope. In particular, we present a spectrum of the variable star π 1 Gru, with observed CO molecular absorption bands, at a resolving power R = 2500 at 1600 nm. Furthermore, we successfully demonstrate the simultaneous acquisition of multiple spectra with a single spectrograph chip by using multiple fibre inputs.

  14. Detectors for the James Webb Space Telescope near-infrared spectrograph

    NASA Astrophysics Data System (ADS)

    Rauscher, Bernard J.; Figer, Donald F.; Regan, Michael W.; Boeker, Torsten; Garnett, James; Hill, Robert J.; Bagnasco, Giorgio; Balleza, Jesus; Barney, Richard; Bergeron, Louis E.; Brambora, Clifford; Connelly, Joe; Derro, Rebecca; DiPirro, Michael J.; Doria-Warner, Christina; Ericsson, Aprille; Glazer, Stuart D.; Greene, Charles; Hall, Donald N.; Jacobson, Shane; Jakobsen, Peter; Johnson, Eric; Johnson, Scott D.; Krebs, Carolyn; Krebs, Danny J.; Lambros, Scott D.; Likins, Blake; Manthripragada, Sridhar; Martineau, Robert J.; Morse, Ernie C.; Moseley, Samuel H.; Mott, D. Brent; Muench, Theo; Park, Hongwoo; Parker, Susan; Polidan, Elizabeth J.; Rashford, Robert; Shakoorzadeh, Kamdin; Sharma, Rajeev; Strada, Paolo; Waczynski, Augustyn; Wen, Yiting; Wong, Selmer; Yagelowich, John; Zuray, Monica

    2004-10-01

    The Near-Infrared Spectrograph (NIRSpec) is the James Webb Space Telescope"s primary near-infrared spectrograph. NASA is providing the NIRSpec detector subsystem, which consists of the focal plane array, focal plane electronics, cable harnesses, and software. The focal plane array comprises two closely-butted λco ~ 5 μm Rockwell HAWAII-2RG sensor chip assemblies. After briefly describing the NIRSpec instrument, we summarize some of the driving requirements for the detector subsystem, discuss the baseline architecture (and alternatives), and presents some recent detector test results including a description of a newly identified noise component that we have found in some archival JWST test data. We dub this new noise component, which appears to be similar to classical two-state popcorn noise in many aspects, "popcorn mesa noise." We close with the current status of the detector subsystem development effort.

  15. An integral field spectrograph design concept for the terrestrial planet finder coronagraph

    NASA Astrophysics Data System (ADS)

    Woodgate, Bruce; Mentzell, Eric; Hilton, George; Lindler, Don

    2006-06-01

    An integral field spectrograph following the TPF coronagraph can provide the required spectral resolving power R ˜ 70 with spatial resolution at the telescope diffraction limit, and covering the coronagraphic dark hole. This allows spectra to be obtained of all planets around the star simultaneously, spectra of disks, measurement of residual speckles for subtraction, and insensitivity to roll control and alignment. Short spectra and the many spatial elements required are most easily implemented using a microlens array at the entrance to a prism spectrograph. To minimize the size of the special photon-counting CCD detectors required, a high filling factor of detector pixel usage is desired. This can be accomplished by using a crossed cylindrical microlens array to create virtual slits at the focus of each lenslet. The lenslets must be illuminated by a highly asymmetric image scale, for which we use cylindrical mirrors to magnify the image in one direction while de-magnifying in the orthogonal direction.

  16. The Colorado High-Resolution Echelle Stellar Spectrograph (CHESS) Design and Status

    NASA Astrophysics Data System (ADS)

    Beasley, Matthew

    I present a new far-ultraviolet echelle spectrograph, which will provide resolving power greater than any currently existing far-ultraviolet instrument. We are using new gratings, detectors, and coatings that allow substantial advances in performance. I will present the current status of the design, and discuss known challenges and our plans to resolve them. While the design purpose of this instrument is for observations of nearby hot stars, the technologies we incorporate will allow for advances relevant to observation subjects from protoplanetary disks to the intergalactic medium. Incorporating such a spectrograph into a future, long-duration mission will make new high-quality observations possible and enhance our understanding of astrophysical plasmas.

  17. An Integral-Field Spectrograph for a Terrestrial Planet Finding Mission

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.

    2011-01-01

    We describe a conceptual design for an integral field spectrograph for characterizing exoplanets that we developed for NASA's Terrestrial Planet Finder Coronagraph (TPF-C), although it is equally applicable to an external-occulter mission. The spectrograph fulfills all four scientific objectives of a terrestrial planet finding mission by: (1) Spectrally characterizing the atmospheres of detected planets in search of signatures of habitability or even biological activity; (2) Directly detecting terrestrial planets in the habitable zone around nearby stars; (3) Studying all constituents of a planetary system including terrestrial and giant planets, gas and dust around sun-like stars of different ages and metallicities; (4) Enabling simultaneous, high-spatial-resolution, spectroscopy of all astrophysical sources regardless of central source luminosity, such as AGN's, proplyds, etc.

  18. Compact Optoelectronic Compass

    NASA Technical Reports Server (NTRS)

    Christian, Carl

    2004-01-01

    A compact optoelectronic sensor unit measures the apparent motion of the Sun across the sky. The data acquired by this chip are processed in an external processor to estimate the relative orientation of the axis of rotation of the Earth. Hence, the combination of this chip and the external processor finds the direction of true North relative to the chip: in other words, the combination acts as a solar compass. If the compass is further combined with a clock, then the combination can be used to establish a threeaxis inertial coordinate system. If, in addition, an auxiliary sensor measures the local vertical direction, then the resulting system can determine the geographic position. This chip and the software used in the processor are based mostly on the same design and operation as those of the unit described in Micro Sun Sensor for Spacecraft (NPO-30867) elsewhere in this issue of NASA Tech Briefs. Like the unit described in that article, this unit includes a small multiple-pinhole camera comprising a micromachined mask containing a rectangular array of microscopic pinholes mounted a short distance in front of an image detector of the active-pixel sensor (APS) type (see figure). Further as in the other unit, the digitized output of the APS in this chip is processed to compute the centroids of the pinhole Sun images on the APS. Then the direction to the Sun, relative to the compass chip, is computed from the positions of the centroids (just like a sundial). In the operation of this chip, one is interested not only in the instantaneous direction to the Sun but also in the apparent path traced out by the direction to the Sun as a result of rotation of the Earth during an observation interval (during which the Sun sensor must remain stationary with respect to the Earth). The apparent path of the Sun across the sky is projected on a sphere. The axis of rotation of the Earth lies at the center of the projected circle on the sphere surface. Hence, true North (not magnetic

  19. HETDEX: Developing the HET's Second Generation Low Resolution Spectrograph for Probing Lyman-alpha Emitting Galaxies

    NASA Astrophysics Data System (ADS)

    Chonis, Taylor S.; Hill, G. J.; Lee, H.; Tuttle, S. E.; Vattiat, B. L.; Gebhardt, K.; Finkelstein, S. L.; Adams, J. J.; HETDEX Collaboration

    2012-01-01

    HETDEX will map the power spectrum of 0.8 million blindly discovered Lyman-alpha Emitting Galaxies (LAE) using a revolutionary new array of massively replicated fiber-fed spectrographs dubbed the Visible Integral-Field Replicable Unit Spectrograph (VIRUS). In the era of the Hobby-Eberly Telescope wide-field upgrade and VIRUS, the current Low Resolution Spectrograph (LRS) must be replaced with a fiber instrument. We discuss the development of the second generation LRS (LRS2), which is a multi-channel instrument based on the VIRUS design. In its current design phase, it is fed by a 287 fiber microlens coupled integral field unit that covers 7” x 12” with 0.62” resolution. The instrument covers 3720 Å to 4700 Å at R ≈ 1900 and 4600 Å to 7000 Å at R ≈1200. With the purpose of making the instrument ideal for follow-up observations of LAE in the HETDEX survey, we discuss the science drivers for selecting the instrument's spectral resolution. We test the utility of the instrument and pilot a future study with LRS2 by presenting R ≈ 2000 spectra taken with the VIRUS prototype spectrograph (VIRUS-P) in a high-resolution mode at the McDonald Observatory Harlan J. Smith 2.7 m telescope. These LAE were originally discovered in the HETDEX Pilot Survey and their Lyman-alpha line profiles are constrained by near-infrared observations of rest-frame optical emission lines that set the systemic redshift of the galaxies. We discuss the velocity offsets of the Lyman-alpha line from the systemic line center and compare the line profiles to theoretical predictions and to similar observations for Lyman-break galaxies. Our observations provide an example of how LRS2 can be used to probe Lyman-alpha emission in 2 < z < 3 star forming galaxies.

  20. Variability in the vacuum-ultraviolet transmittance of magnesium fluoride windows. [for Space Telescope Imaging Spectrograph

    NASA Technical Reports Server (NTRS)

    Herzig, Howard; Fleetwood, Charles M., Jr.; Toft, Albert R.

    1992-01-01

    Sample window materials tested during the development of a domed magnesium fluoride detector window for the Hubble Space Telescope's Imaging Spectrograph are noted to exhibit wide variability in VUV transmittance; a test program was accordingly instituted to maximize a prototype domed window's transmittance. It is found that VUV transmittance can be maximized if the boule from which the window is fashioned is sufficiently large to allow such a component to be cut from the purest available portion of the boule.

  1. Emission spectrographic determination of barium in sea water using a cation exchange concentration procedure

    USGS Publications Warehouse

    Szabo, B. J.; Joensuu, O.

    1967-01-01

    A concentration technique employing Dowex 50W cation exchange resin is described for the determination of barium in sea water. The separated barium is precipitated as fluoride together with calcium and strontium and measured by emission spectrographic analysis. The vertical distribution of barium in sea water has been measured in the Caribbean Sea and the Atlantic Ocean. The barium content varied between 7 and 23 ??g. per liter; in two profiles, the lowest concentrations were at a depth of about 1000 meters.

  2. Concave grating and convex mirror double dispersion spectrograph for optical network applications

    NASA Astrophysics Data System (ADS)

    Churin, Evgeny G.; Bayvel, Polina; Smirnitskii, Vladimir B.; Timofeev, Fedor N.; Midwinter, John E.

    1997-10-01

    The concave grating stationary anastigmatic spectrograph has been modified into a novel retroreflective scheme by introducing a convex mirror concentric to the intermediate image. This provides double dispersion, diffraction-limited imaging of a long entrance slit, and substantial compensation of the stationary chromatic astigmatism. One can realize 140 independent multi demultiplexers with 160 channels each simultaneously in the described device for optical network applications. Ray-tracing spot diagrams are presented.

  3. Designing the optimal semi-warm NIR spectrograph for SALT via detailed thermal analysis

    NASA Astrophysics Data System (ADS)

    Wolf, Marsha J.; Sheinis, Andrew I.; Mulligan, Mark P.; Wong, Jeffrey P.; Rogers, Allen

    2008-07-01

    The near infrared (NIR) upgrade to the Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT), RSS/NIR, extends the spectral coverage of all modes of the optical spectrograph. The RSS/NIR is a low to medium resolution spectrograph with broadband, spectropolarimetric, and Fabry-Perot imaging capabilities. The optical and NIR arms can be used simultaneously to extend spectral coverage from 3200 Å to approximately 1.6 μm. Both arms utilize high efficiency volume phase holographic gratings via articulating gratings and cameras. The NIR camera incorporates a HAWAII-2RG detector with an Epps optical design consisting of 6 spherical elements and providing subpixel rms image sizes of 7.5 +/- 1.0 μm over all wavelengths and field angles. The NIR spectrograph is semi-warm, sharing a common slit plane and partial collimator with the optical arm. A pre-dewar, cooled to below ambient temperature, houses the final NIR collimator optic, the grating/Fabry-Perot etalon, the polarizing beam splitter, and the first three camera optics. The last three camera elements, blocking filters, and detector are housed in a cryogenically cooled dewar. The semi-warm design concept has long been proposed as an economical way to extend optical instruments into the NIR, however, success has been very limited. A major portion of our design effort entails a detailed thermal analysis using non-sequential ray tracing to interactively guide the mechanical design and determine a truly realizable long wavelength cutoff over which astronomical observations will be sky-limited. In this paper we describe our thermal analysis, design concepts for the staged cooling scheme, and results to be incorporated into the overall mechanical design and baffling.

  4. Construction and Tests of an Ebert-Fastie Spectrograph with Optical Fibers

    NASA Astrophysics Data System (ADS)

    Cardona, O.; Furenlid, L.; Cornejo, A.

    1990-11-01

    RESUMEN. Se presenta el desarrollo, , pruebas de laboratoric y observacionales de un espectr6grafo tipo Ebert-Fastie fuera del plano con fibras 6pticas. Tambien se dan algunos resultados observacionales. ABSTRACT. We present the development, laboratory and observational tests of an spectrograph of the off-plane Ebert-Fastie type with optical fibers, we also give some observational results. Key words: INSTRUMENTS - SPECTROSCOPY - RADIAL VELOCITIES

  5. A Prototype Fringing Spectrograph for Sensitive Extra-solar Planet Searches and Astroseismology studies

    NASA Astrophysics Data System (ADS)

    Erskine, D.; Ge, J.

    1999-05-01

    We have developed a prototype fringing spectrograph optimized for sensitive stellar radial velocity measurements, aimed at detecting small extra-solar planet velocity perturbation and stellar seismology on an amplitude of ~ 1 m s(-1) or less. It is a combination of an angle-independent interferometer and a high throughput intermediate resolution spectrograph. The interferometer is used for measuring phase shifts caused by radial velocity variations of star light, while the spectrograph is applied for dispersing broad-band white fringes into different color channels to increase fringe visibility for precision phase measurements. A much simplified instrument response function (PSF), determined only by phase, amplitude and offset, compared to much more complicated ones in conventional echelle spectrographs, provides unprecedented sensitivity for radial velocity measurements. Preliminary lab-based experiments with this prototype instrument demonstrate 0.7 m s(-1) accuracy for short term radial velocity measurements. The zero point drift over 11 days was within 4 m s(-1) and may be due to the lack of interferometer stabilization during these runs. Stabilization is now being implemented through a close-loop electronics. This is expected to improve long term velocity measurement accuracy and make the instrument ready for first-light stellar observations. The instrument is also being tested with sunlight. The diurnal velocity variation caused by the Earth's rotation has been observed. Work to measure solar P-mode 5 minute oscillations is underway. This work is supported by the LLNL Laboratory Directed Research and Development (LDRD) grant through track 98-ERD-054.

  6. FLECHAS - A new échelle spectrograph at the University Observatory Jena

    NASA Astrophysics Data System (ADS)

    Mugrauer, M.; Avila, G.; Guirao, C.

    The new échelle spectrograph FLECHAS (Fibre Linked ECHelle Astronomical Spectrograph) is in operation at the Nasmyth-focus of the 0.9 m telescope of the University Observatory Jena. FLECHAS is equipped with a sensitive back-illuminated and midband coated CCD-detector, as well as with a calibration unit for flatfield and wavelength-calibration. The spectrograph covers the spectral range between about 3900 and 8100 Åand exhibits a resolving power of R˜9300. In this article all technical characteristics of FLECHAS are described and examples of the first astronomical observations obtained with the new instrument in July 2013 at the University Observatory Jena are presented, among them the first light spectra taken with FLECHAS, simultaneous imaging and spectroscopic observations, the determination of the detection limit of the instrument, the spectroscopy of stars of different spectral types and of faint extended objects, as well as the Li-line detection in the spectra of young solar-like stars. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University.

  7. Methods for evaluating the performance of volume phase holographic gratings for the VIRUS spectrograph array

    NASA Astrophysics Data System (ADS)

    Chonis, Taylor S.; Hill, Gary J.; Clemens, J. Christopher; Dunlap, Bart; Lee, Hanshin

    2012-09-01

    The Visible Integral field Replicable Unit Spectrograph (VIRUS) is an array of at least 150 copies of a simple, fiber-fed integral field spectrograph that will be deployed on the Hobby-Eberly Telescope (HET) to carry out the HET Dark Energy Experiment (HETDEX). Each spectrograph contains a volume phase holographic grating as its dispersing element that is used in first order for 350 < λ(nm) < 550. We discuss the test methods used to evaluate the performance of the prototype gratings, which have aided in modifying the fabrication prescription for achieving the specified batch diffraction efficiency required for HETDEX. In particular, we discuss tests in which we measure the diffraction efficiency at the nominal grating angle of incidence in VIRUS for all orders accessible to our test bench that are allowed by the grating equation. For select gratings, these tests have allowed us to account for < 90% of the incident light for wavelengths within the spectral coverage of VIRUS. The remaining light that is unaccounted for is likely being diffracted into reflective orders or being absorbed or scattered within the grating layer (for bluer wavelengths especially, the latter term may dominate the others). Finally, we discuss an apparatus that will be used to quickly verify the first order diffraction efficiency specification for the batch of at least 150 VIRUS production gratings.

  8. Mass production of volume phase holographic gratings for the VIRUS spectrograph array

    NASA Astrophysics Data System (ADS)

    Chonis, Taylor S.; Frantz, Amy; Hill, Gary J.; Clemens, J. Christopher; Lee, Hanshin; Tuttle, Sarah E.; Adams, Joshua J.; Marshall, J. L.; DePoy, D. L.; Prochaska, Travis

    2014-07-01

    The Visible Integral-field Replicable Unit Spectrograph (VIRUS) is a baseline array of 150 copies of a simple, fiber-fed integral field spectrograph that will be deployed on the Hobby-Eberly Telescope (HET). VIRUS is the first optical astronomical instrument to be replicated on an industrial scale, and represents a relatively inexpensive solution for carrying out large-area spectroscopic surveys, such as the HET Dark Energy Experiment (HETDEX). Each spectrograph contains a volume phase holographic (VPH) grating with a 138 mm diameter clear aperture as its dispersing element. The instrument utilizes the grating in first-order for 350 < λ (nm) < 550. Including witness samples, a suite of 170 VPH gratings has been mass produced for VIRUS. Here, we present the design of the VIRUS VPH gratings and a discussion of their mass production. We additionally present the design and functionality of a custom apparatus that has been used to rapidly test the first-order diffraction efficiency of the gratings for various discrete wavelengths within the VIRUS spectral range. This device has been used to perform both in-situ tests to monitor the effects of adjustments to the production prescription as well as to carry out the final acceptance tests of the gratings' diffraction efficiency. Finally, we present the as-built performance results for the entire suite of VPH gratings.

  9. A color spectrographic phonocardiography (CSP) applied to the detection and characterization of heart murmurs: preliminary results

    PubMed Central

    2011-01-01

    Background Although cardiac auscultation remains important to detect abnormal sounds and murmurs indicative of cardiac pathology, the application of electronic methods remains seldom used in everyday clinical practice. In this report we provide preliminary data showing how the phonocardiogram can be analyzed using color spectrographic techniques and discuss how such information may be of future value for noninvasive cardiac monitoring. Methods We digitally recorded the phonocardiogram using a high-speed USB interface and the program Gold Wave http://www.goldwave.com in 55 infants and adults with cardiac structural disease as well as from normal individuals and individuals with innocent murmurs. Color spectrographic analysis of the signal was performed using Spectrogram (Version 16) as a well as custom MATLAB code. Results Our preliminary data is presented as a series of seven cases. Conclusions We expect the application of spectrographic techniques to phonocardiography to grow substantially as ongoing research demonstrates its utility in various clinical settings. Our evaluation of a simple, low-cost phonocardiographic recording and analysis system to assist in determining the characteristic features of heart murmurs shows promise in helping distinguish innocent systolic murmurs from pathological murmurs in children and is expected to useful in other clinical settings as well. PMID:21627809

  10. Mechanical design of the near-infrared arm of the Robert Stobie Spectrograph for SALT

    NASA Astrophysics Data System (ADS)

    Smith, Michael P.; Mason, William P.; Wong, Jeffrey P.; Adler, Douglas P.; Smee, Stephen; Rogers, Allen R.; Mulligan, Mark P.; Percival, Jeffrey W.; Sheinis, Andrew I.; Thielman, Donald J.; Wolf, Marsha J.

    2010-07-01

    The Robert Stobie Spectrograph Near Infrared (RSS/NIR) upgrade for the Southern African Large Telescope (SALT) extends the capabilities of the visible arm of RSS into the NIR. The RSS/NIR instrument is at the prime focus of SALT. It is a versatile spectrograph with broadband imaging, spectropolarimetric, and Fabry-Perot imaging capabilities. The multiple modes and prime focus location introduce interesting engineering considerations. The spectrograph has an ambient temperature collimator, cooled (-40ºC) dispersers and camera and a cryogenic detector. Many of the mechanisms are required to operate within the cooled and cryogenic environments. The RSS/ NIR upgrade includes the following mechanisms; an active flexure compensating fold mirror, a filter exchange mechanism, a Volume Phase Holographic VPH grating exchange and rotation mechanism, an etalon inserter, a beam splitter inserter, an articulating camera, internal camera focus and a cutoff filter exchange wheel. This paper gives an overview of the mechanical design and focuses on some of the unique testing and prototyping tasks.

  11. A Flexible and Modular Data Reduction Library for Fiber-fed Echelle Spectrographs

    NASA Astrophysics Data System (ADS)

    Sosnowska, D.; Lovis, C.; Figueira, P.; Modigliani, A.; Marcantonio, P. D.; Megevand, D.; Pepe, F.

    2015-09-01

    Within the ESPRESSO project a new flexible data reduction library is being built. ESPRESSO, the Echelle SPectrograph for Rocky Exoplanets and Stable Spectral Observations is a fiber-fed, high-resolution, cross-dispersed echelle spectrograph. One of its main scientific goals is to search for terrestrial exoplanets using the radial velocity technique. A dedicated pipeline is being developed. It is designed to be able to reduce data from different similar spectrographs: not only ESPRESSO, but also HARPS, HARPS-N and possibly others. Instrument specifics are configurable through an input static configuration table. The first written recipes are already tested on HARPS and HARPS-N real data and ESPRESSO simulated data. The final scientific products of the pipeline will be the extracted 1-dim and 2-dim spectra. Using these products the radial velocity of the observed object can be computed with high accuracy. The library is developed within the standard ESO pipeline environment. It is being written in ANSI C and makes use of the Common Pipeline Library (CPL). It can be used in conjunction with the ESO tools Esorex, Gasgano and Reflex in the usual way.

  12. [Design and analysis of a novel light visible spectrum imaging spectrograph optical system].

    PubMed

    Shen, Man-de; Li, Fei; Zhou, Li-bing; Li, Cheng; Ren, Huan-huan; Jiang, Qing-xiu

    2015-02-01

    A novel visible spectrum imaging spectrograph optical system was proposed based on the negative dispersion, the arbitrary phase modulation characteristics of diffractive optical element and the aberration correction characteristics of freeform optical element. The double agglutination lens was substituted by a hybrid refractive/diffractive lens based on the negative dispersion of diffractive optical element. Two freeform optical elements were used in order to correct some aberration based on the aberration correction characteristics of freeform optical element. An example and frondose design process were presented. When the design parameters were uniform, compared with the traditional system, the novel visible spectrum imaging spectrograph optical system's weight was reduced by 22.9%, the total length was reduced by 26.6%, the maximal diameter was reduced by 30.6%, and the modulation transfer function (MTF) in 1.0 field-of-view was improved by 0.35 with field-of-view improved maximally. The maximal distortion was reduced by 1.6%, the maximal longitudinal aberration was reduced by 56.4%, and the lateral color aberration was reduced by 59. 3%. From these data, we know that the performance of the novel system was advanced quickly and it could be used to put forward a new idea for modern visible spectrum imaging spectrograph optical system design.

  13. The infrared imaging spectrograph (IRIS) for TMT: overview of innovative science programs

    NASA Astrophysics Data System (ADS)

    Wright, Shelley A.; Larkin, James E.; Moore, Anna M.; Do, Tuan; Simard, Luc; Adamkovics, Maté; Armus, Lee; Barth, Aaron J.; Barton, Elizabeth; Boyce, Hope; Cooke, Jeffrey; Cote, Patrick; Davidge, Timothy; Ellerbroek, Brent; Ghez, Andrea M.; Liu, Michael C.; Lu, Jessica R.; Macintosh, Bruce A.; Mao, Shude; Marois, Christian; Schoeck, Matthias; Suzuki, Ryuji; Tan, Jonathan C.; Treu, Tommaso; Wang, Lianqi; Weiss, Jason

    2014-07-01

    IRIS (InfraRed Imaging Spectrograph) is a first light near-infrared diffraction limited imager and integral field spectrograph being designed for the future Thirty Meter Telescope (TMT). IRIS is optimized to perform astronomical studies across a significant fraction of cosmic time, from our Solar System to distant newly formed galaxies (Barton et al. [1]). We present a selection of the innovative science cases that are unique to IRIS in the era of upcoming space and ground-based telescopes. We focus on integral field spectroscopy of directly imaged exoplanet atmospheres, probing fundamental physics in the Galactic Center, measuring 104 to 1010 M supermassive black hole masses, resolved spectroscopy of young star-forming galaxies (1 < z < 5) and first light galaxies (6 < z < 12), and resolved spectroscopy of strong gravitational lensed sources to measure dark matter substructure. For each of these science cases we use the IRIS simulator (Wright et al. [2], Do et al. [3]) to explore IRIS capabilities. To highlight the unique IRIS capabilities, we also update the point and resolved source sensitivities for the integral field spectrograph (IFS) in all five broadband filters (Z, Y, J, H, K) for the finest spatial scale of 0.004" per spaxel. We briefly discuss future development plans for the data reduction pipeline and quicklook software for the IRIS instrument suite.

  14. Directional Oscillations, Concentrations, and Compensated Compactness via Microlocal Compactness Forms

    NASA Astrophysics Data System (ADS)

    Rindler, Filip

    2015-01-01

    This work introduces microlocal compactness forms (MCFs) as a new tool to study oscillations and concentrations in L p -bounded sequences of functions. Decisively, MCFs retain information about the location, value distribution, and direction of oscillations and concentrations, thus extending at the same time the theories of (generalized) Young measures and H-measures. In L p -spaces oscillations and concentrations precisely discriminate between weak and strong compactness, and thus MCFs allow one to quantify the difference in compactness. The definition of MCFs involves a Fourier variable, whereby differential constraints on the functions in the sequence can also be investigated easily—a distinct advantage over Young measure theory. Furthermore, pointwise restrictions are reflected in the MCF as well, paving the way for applications to Tartar's framework of compensated compactness; consequently, we establish a new weak-to-strong compactness theorem in a "geometric" way. After developing several aspects of the abstract theory, we consider three applications; for lamination microstructures, the hierarchy of oscillations is reflected in the MCF. The directional information retained in an MCF is harnessed in the relaxation theory for anisotropic integral functionals. Finally, we indicate how the theory pertains to the study of propagation of singularities in certain systems of PDEs. The proofs combine measure theory, Young measures, and harmonic analysis.

  15. Characterization and monitoring of Flamingos-II, a near-IR imager and spectrograph at Gemini South

    NASA Astrophysics Data System (ADS)

    Krogsrud, David; Diaz, Ruben; Ferrero, Gabriel; Mora, Marcelo; Navarete, Felipe; Schirmer, Mischa

    2015-01-01

    We present results of the characterization and continual monitoring of the Flamingos-II instrument. Currently installed at Gemini South Observatory, Flamingos-II is a near-IR imager and longslit/multi-object spectrograph. In addition to the characterization of the detector, methodologies and results of the Science Verification pipeline, Telluric corrections, and Multi-Object Spectrograph (MOS) mask design software are presented.

  16. IntelliCal: A Novel Method For Calibration Of Imaging Spectrographs

    NASA Astrophysics Data System (ADS)

    McClure, Jason; Gooding, Ed

    2010-08-01

    The wavelength accuracy of traditional spectrograph calibration software routines relies heavily on user input and familiarity with spectroscopic techniques. A simple misunderstanding in programmatic procedures or misfit of emission lines can easily result in an inaccurate calibration. After such calibration routines terminate, there is typically no way of determining wavelength accuracy without subsequent peak fitting of emission line spectra for comparison. Furthermore, adjusting calibration parameters to optimize observed spectral dispersion across the focal plane of an imaging spectrograph is not a trivial task and one usually left for the user to determine. It is historically the case that Raman spectra collected with dispersive spectrometers are generally not corrected for the instrumental response function. Spectra obtained from different instruments may therefore show variations in relative peak intensities as a result of the wavelength dependant optical properties of the instrument and quantum efficiency of the detector. The determination and implementation of the spectrometer's optical response function is, additionally, left as an exercise for the user. We present the results of a novel spectrograph calibration routine that utilizes non-linear optimization techniques to refine a theoretical spectrograph model. Calculated emission line spectra are refined against observed data at the CCD detector pixel level providing a true wavelength to pixel correlation that does not involve any approximation techniques. Moreover, this calibration routine proceeds autonomously, requiring no sophistication on the part of the end user and eliminating potential sources of user error. Instrumental response functions are determined through the autonomous implementation of the methods outlined by Choquette at. al. Secondary emission standards that are luminescent under laser excitation are used as broad band continuous sources whose relative irradiance functions are known

  17. Blue ellipticals in compact groups

    NASA Technical Reports Server (NTRS)

    Zepf, Stephen E.; Whitmore, Bradley C.

    1990-01-01

    By studying galaxies in compact groups, the authors examine the hypothesis that mergers of spiral galaxies make elliptical galaxies. The authors combine dynamical models of the merger-rich compact group environment with stellar evolution models and predict that roughly 15 percent of compact group ellipticals should be 0.15 mag bluer in B - R color than normal ellipticals. The published colors of these galaxies suggest the existence of this predicted blue population, but a normal distribution with large random errors can not be ruled out based on these data alone. However, the authors have new ultraviolet blue visual data which confirm the blue color of the two ellipticals with blue B - R colors for which they have their own colors. This confirmation of a population of blue ellipticals indicates that interactions are occurring in compact groups, but a blue color in one index alone does not require that these ellipticals are recent products of the merger of two spirals. The authors demonstrate how optical spectroscopy in the blue may distinguish between a true spiral + spiral merger and the swallowing of a gas-rich system by an already formed elliptical. The authors also show that the sum of the luminosity of the galaxies in each group is consistent with the hypothesis that the final stage in the evolution of compact group is an elliptical galaxy.

  18. Viral RNAs Are Unusually Compact

    PubMed Central

    Gopal, Ajaykumar; Egecioglu, Defne E.; Yoffe, Aron M.; Ben-Shaul, Avinoam; Rao, Ayala L. N.; Knobler, Charles M.; Gelbart, William M.

    2014-01-01

    A majority of viruses are composed of long single-stranded genomic RNA molecules encapsulated by protein shells with diameters of just a few tens of nanometers. We examine the extent to which these viral RNAs have evolved to be physically compact molecules to facilitate encapsulation. Measurements of equal-length viral, non-viral, coding and non-coding RNAs show viral RNAs to have among the smallest sizes in solution, i.e., the highest gel-electrophoretic mobilities and the smallest hydrodynamic radii. Using graph-theoretical analyses we demonstrate that their sizes correlate with the compactness of branching patterns in predicted secondary structure ensembles. The density of branching is determined by the number and relative positions of 3-helix junctions, and is highly sensitive to the presence of rare higher-order junctions with 4 or more helices. Compact branching arises from a preponderance of base pairing between nucleotides close to each other in the primary sequence. The density of branching represents a degree of freedom optimized by viral RNA genomes in response to the evolutionary pressure to be packaged reliably. Several families of viruses are analyzed to delineate the effects of capsid geometry, size and charge stabilization on the selective pressure for RNA compactness. Compact branching has important implications for RNA folding and viral assembly. PMID:25188030

  19. Compact orthogonal NMR field sensor

    SciTech Connect

    Gerald, II, Rex E.; Rathke, Jerome W.

    2009-02-03

    A Compact Orthogonal Field Sensor for emitting two orthogonal electro-magnetic fields in a common space. More particularly, a replacement inductor for existing NMR (Nuclear Magnetic Resonance) sensors to allow for NMR imaging. The Compact Orthogonal Field Sensor has a conductive coil and a central conductor electrically connected in series. The central conductor is at least partially surrounded by the coil. The coil and central conductor are electrically or electro-magnetically connected to a device having a means for producing or inducing a current through the coil and central conductor. The Compact Orthogonal Field Sensor can be used in NMR imaging applications to determine the position and the associated NMR spectrum of a sample within the electro-magnetic field of the central conductor.

  20. Compaction Stress in Fine Powders

    SciTech Connect

    Hurd, A.J.; Kenkre, V.M.; Pease, E.A.; Scott, J.E.

    1999-04-01

    A vexing feature in granular materials compaction is density extrema interior to a compacted shape. Such inhomogeneities can lead to weaknesses and loss of dimensional control in ceramic parts, unpredictable dissolution of pharmaceuticals, and undesirable stress concentration in load-bearing soil. As an example, the centerline density in a cylindrical compact often does not decrease monotonically from the pressure source but exhibits local maxima and minima. Two lines of thought in the literature predict, respectively, diffusive and wavelike propagation of stress. Here, a general memory function approach has been formulated that unifies these previous treatments as special cases; by analyzing a convenient intermediate case, the telegrapher's equation, one sees that local density maxima arise via semidiffusive stress waves reflecting from the die walls and adding constructively at the centerline.

  1. Compact remote multisensing instrument for planetary surfaces and atmospheres characterization.

    PubMed

    Nurul Abedin, M; Bradley, Arthur T; Ismail, Syed; Sharma, Shiv K; Sandford, Stephen P

    2013-05-10

    This paper describes a prototype feasibility demonstration system of a multipurpose Raman-fluorescence spectrograph and compact lidar system suitable for planetary sciences missions. The key measurement features of this instrument are its abilities to: i) detect minerals and organics at low levels in the dust constituents of surface, subsurface material and rocks on Mars, ii) determine the distribution of trace fluorescent ions with time-resolved fluorescence spectroscopy to learn about the geological conditions under which these minerals formed, iii) inspect material toxicity from a mobile robotic platform during local site characterization, iv) measure dust aerosol and cloud distributions, v) measure near-field atmospheric carbon dioxide, and vi) identify surface CO(2)-ice, surface water ice, and surface or subsurface methane hydrate. This prototype instrument and an improved follow-on design are described and have the capability for scientific investigations discussed above, to remotely investigate geological processes from a robotic platform at more than a 20-m radial distance with potential to go beyond 100 m. It also provides single wavelength (532 nm) aerosol/cloud profiling over very long ranges (>10 km with potential to 20 km). Measurement results obtained with this prototype unit from a robotic platform and calculated potential performance are presented in this paper. PMID:23669823

  2. Compact remote multisensing instrument for planetary surfaces and atmospheres characterization.

    PubMed

    Nurul Abedin, M; Bradley, Arthur T; Ismail, Syed; Sharma, Shiv K; Sandford, Stephen P

    2013-05-10

    This paper describes a prototype feasibility demonstration system of a multipurpose Raman-fluorescence spectrograph and compact lidar system suitable for planetary sciences missions. The key measurement features of this instrument are its abilities to: i) detect minerals and organics at low levels in the dust constituents of surface, subsurface material and rocks on Mars, ii) determine the distribution of trace fluorescent ions with time-resolved fluorescence spectroscopy to learn about the geological conditions under which these minerals formed, iii) inspect material toxicity from a mobile robotic platform during local site characterization, iv) measure dust aerosol and cloud distributions, v) measure near-field atmospheric carbon dioxide, and vi) identify surface CO(2)-ice, surface water ice, and surface or subsurface methane hydrate. This prototype instrument and an improved follow-on design are described and have the capability for scientific investigations discussed above, to remotely investigate geological processes from a robotic platform at more than a 20-m radial distance with potential to go beyond 100 m. It also provides single wavelength (532 nm) aerosol/cloud profiling over very long ranges (>10 km with potential to 20 km). Measurement results obtained with this prototype unit from a robotic platform and calculated potential performance are presented in this paper.

  3. Compact monolithic capacitive discharge unit

    DOEpatents

    Roesler, Alexander W.; Vernon, George E.; Hoke, Darren A.; De Marquis, Virginia K.; Harris, Steven M.

    2007-06-26

    A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

  4. Compact intermediates in RNA folding

    SciTech Connect

    Woodson, S.A.

    2011-12-14

    Large noncoding RNAs fold into their biologically functional structures via compact yet disordered intermediates, which couple the stable secondary structure of the RNA with the emerging tertiary fold. The specificity of the collapse transition, which coincides with the assembly of helical domains, depends on RNA sequence and counterions. It determines the specificity of the folding pathways and the magnitude of the free energy barriers to the ensuing search for the native conformation. By coupling helix assembly with nascent tertiary interactions, compact folding intermediates in RNA also play a crucial role in ligand binding and RNA-protein recognition.

  5. Compact accelerator for medical therapy

    DOEpatents

    Caporaso, George J.; Chen, Yu-Jiuan; Hawkins, Steven A.; Sampayan, Stephen E.; Paul, Arthur C.

    2010-05-04

    A compact accelerator system having an integrated particle generator-linear accelerator with a compact, small-scale construction capable of producing an energetic (.about.70-250 MeV) proton beam or other nuclei and transporting the beam direction to a medical therapy patient without the need for bending magnets or other hardware often required for remote beam transport. The integrated particle generator-accelerator is actuable as a unitary body on a support structure to enable scanning of a particle beam by direction actuation of the particle generator-accelerator.

  6. Spectroscopic Survey of Eclipsing Binaries with a Low-cost Echelle Spectrograph: Scientific Commissioning

    NASA Astrophysics Data System (ADS)

    Kozłowski, S. K.; Konacki, M.; Sybilski, P.; Ratajczak, M.; Pawłaszek, R. K.; Hełminiak, K. G.

    2016-07-01

    We present scientific results obtained with a recently commissioned échelle spectrograph on the 0.5 m Solaris-1 telescope in the South African Astronomical Observatory. BACHES is a low-cost slit échelle spectrograph that has a resolution of 21,000 at 5500 Å. The described setup is fully remotely operated and partly automated. Custom hardware components have been designed to allow both spectroscopic and photometric observations. The setup is controlled via dedicated software. The throughput of the system allows us to obtain spectra with an average signal-to-noise ratio of 22 at 6375 Å for a 30 minute exposure of a V = 10 mag target. The stability of the instrument is influenced mainly by the ambient temperature changes. We have obtained radial velocity (RV) rms values for a bright (V = 5.9 mag) spectroscopic binary as good as 0.59 and 1.34 km s‑1 for a V = 10.2 mag eclipsing binary. RV measurements have been combined with available photometric light curves. We present models of six eclipsing binary systems, and for previously known targets, we compare our results with those available in the literature. Masses of binary components have been determined with 3% errors for some targets. We confront our results with benchmark values based on measurements from the HARPS and UCLES spectrographs on 4 m class telescopes and find very good agreement. The described setup is very efficient and well suited for a spectroscopic survey. We can now spectroscopically characterize about 300 eclipsing binary stars per year up to 10.2 mag assuming typical weather conditions at SAAO without a single observing trip.

  7. Optimization of a space spectrograph main frame and frequency response analysis of the frame

    NASA Astrophysics Data System (ADS)

    Zhang, Xin-yu; Chen, Zhi-yuan; Yang, Shi-mo

    2009-07-01

    A space spectrograph main structure is optimized and examined in order to satisfy the space operational needs. The space spectrograph will be transported into its operational orbit by the launch vehicle and it will undergo dynamic environment in the spacecraft injection period. The unexpected shocks may cause declination of observation accuracy and even equipment damages. The main frame is one of the most important parts because its mechanical performance has great influence on the operational life of the spectrograph, accuracy of observation, etc. For the reason of cost reduction and stability confirming, lower weight and higher structure stiffness of the frame are simultaneously required. Structure optimization was conducted considering the initial design modal analysis results. The base modal frequency raised 10.34% while the whole weight lowered 8.63% compared to the initial design. The purpose of this study is to analyze the new design of main frame mechanical properties and verify whether it can satisfy strict optical demands under the dynamic impact during spacecraft injection. For realizing and forecasting the frequency response characteristics of the main structure in mechanical environment experiment, dynamic analysis of the structure should be performed simulating impulse loads from the bottom base. Therefore, frequency response analysis (FRA) of the frame was then performed using the FEA software MSC.PATRAN/NASTRAN. Results of shock response spectrum (SRS) responses from the base excitations were given. Stress and acceleration dynamic responses of essential positions in the spacecraft injection course were also calculated and spectrometer structure design was examined considering stiffness / strength demands. In this simulation, maximum stresses of Cesic material in two acceleration application cases are 45.1 and 74.1 MPa, respectively. They are all less than yield strengths. As is demonstrated from the simulation, strength reservation of the frame is

  8. The SLICE, CHESS, and SISTINE Ultraviolet Spectrographs: Rocket-Borne Instrumentation Supporting Future Astrophysics Missions

    NASA Astrophysics Data System (ADS)

    France, Kevin; Hoadley, Keri; Fleming, Brian T.; Kane, Robert; Nell, Nicholas; Beasley, Matthew; Green, James C.

    2016-03-01

    NASA’s suborbital program provides an opportunity to conduct unique science experiments above Earth’s atmosphere and is a pipeline for the technology and personnel essential to future space astrophysics, heliophysics, and atmospheric science missions. In this paper, we describe three astronomy payloads developed (or in development) by the Ultraviolet Rocket Group at the University of Colorado. These far-ultraviolet (UV) (100-160nm) spectrographic instruments are used to study a range of scientific topics, from gas in the interstellar medium (accessing diagnostics of material spanning five orders of magnitude in temperature in a single observation) to the energetic radiation environment of nearby exoplanetary systems. The three instruments, Suborbital Local Interstellar Cloud Experiment (SLICE), Colorado High-resolution Echelle Stellar Spectrograph (CHESS), and Suborbital Imaging Spectrograph for Transition region Irradiance from Nearby Exoplanet host stars (SISTINE) form a progression of instrument designs and component-level technology maturation. SLICE is a pathfinder instrument for the development of new data handling, storage, and telemetry techniques. CHESS and SISTINE are testbeds for technology and instrument design enabling high-resolution (R>105) point source spectroscopy and high throughput imaging spectroscopy, respectively, in support of future Explorer, Probe, and Flagship-class missions. The CHESS and SISTINE payloads support the development and flight testing of large-format photon-counting detectors and advanced optical coatings: NASA’s top two technology priorities for enabling a future flagship observatory (e.g. the LUVOIR Surveyor concept) that offers factors of ˜50-100 gain in UV spectroscopy capability over the Hubble Space Telescope. We present the design, component level laboratory characterization, and flight results for these instruments.

  9. Spectroscopic Survey of Eclipsing Binaries with a Low-cost Echelle Spectrograph: Scientific Commissioning

    NASA Astrophysics Data System (ADS)

    Kozłowski, S. K.; Konacki, M.; Sybilski, P.; Ratajczak, M.; Pawłaszek, R. K.; Hełminiak, K. G.

    2016-07-01

    We present scientific results obtained with a recently commissioned échelle spectrograph on the 0.5 m Solaris-1 telescope in the South African Astronomical Observatory. BACHES is a low-cost slit échelle spectrograph that has a resolution of 21,000 at 5500 Å. The described setup is fully remotely operated and partly automated. Custom hardware components have been designed to allow both spectroscopic and photometric observations. The setup is controlled via dedicated software. The throughput of the system allows us to obtain spectra with an average signal-to-noise ratio of 22 at 6375 Å for a 30 minute exposure of a V = 10 mag target. The stability of the instrument is influenced mainly by the ambient temperature changes. We have obtained radial velocity (RV) rms values for a bright (V = 5.9 mag) spectroscopic binary as good as 0.59 and 1.34 km s-1 for a V = 10.2 mag eclipsing binary. RV measurements have been combined with available photometric light curves. We present models of six eclipsing binary systems, and for previously known targets, we compare our results with those available in the literature. Masses of binary components have been determined with 3% errors for some targets. We confront our results with benchmark values based on measurements from the HARPS and UCLES spectrographs on 4 m class telescopes and find very good agreement. The described setup is very efficient and well suited for a spectroscopic survey. We can now spectroscopically characterize about 300 eclipsing binary stars per year up to 10.2 mag assuming typical weather conditions at SAAO without a single observing trip.

  10. The Limb-Imaging Ionospheric and Thermospheric Extreme-Ultraviolet Spectrograph (LITES) on the ISS

    NASA Astrophysics Data System (ADS)

    Stephan, Andrew W.; Finn, Susanna C.; Cook, Timothy A.; Chakrabarti, Supriya; Budzien, Scott A.

    2015-04-01

    The Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) is being prepared for flight in early 2016 aboard the Space Test Program Houston 5 (STP-H5) experiment pallet to the International Space Station (ISS). LITES is an imaging spectrograph that spans 60-140 nm and will obtain limb profiles of the ionosphere, along with the key upper atmospheric constituents O and N2. During the day, LITES measures the OII 83.4 and 61.7 nm emissions that are produced by solar photoionization of atomic oxygen in the lower thermosphere. The 83.4 nm emission is resonantly scattered by ionospheric O+, and thus its altitude profile is formed by both the initial ionization brightness and the ionospheric content. The 61.7 nm emission is not scattered and is used to constrain the photoionization brightness in the retrieval. At night, recombination of O+ and electrons produces optically thin emissions at 91.1 and 135.6 nm that are used to tomographically reconstruct the two-dimensional ionosphere in the orbital plane.These observations will be complemented and validated by ground-based data from an international network of digisondes, visible spectrographs, and imagers, which will provide ground truth for the space-based measurements. Additionally, the STP-H5 mission includes the GPS Radio Occultation and Ultraviolet Photometer Co-located (GROUP-C) experiment that consists of a high-sensitivity, nadir-viewing photometer that measures the nighttime ionospheric airglow at 135.6 nm, and a GPS receiver that measures ionospheric electron content and scintillation. We will discuss the LITES measurements and science goals, and how LITES data will be combined with these other experiments to study low and middle latitude ionospheric structures on a global scale.

  11. The Calibration System for IGRINS, a High Resolution Near-IR Spectrograph

    NASA Astrophysics Data System (ADS)

    Oh, Heeyoung; Pak, S.; Yuk, I.; Jaffe, D. T.; Park, C.; Lee, S.; Lee, S.; Chun, M.; Lee, H.; Strubhar, J.; Kim, K.; Pyo, T.; Seo, H.; Barnes, S. I.

    2010-05-01

    IGRINS (the Immersion GRating INfrared Spectrograph) is a high resolution infrared spectrograph which is developed by a collaboration of the University of Texas at Austin, Korea Astronomy and Space Science Institute, and Kyung Hee University. IGRINS is the forerunner for GMTNIRS (the Giant Magellan Telescope Near Infrared Spectrograph) which has been selected for study as a first-light instrument for GMT. IGRINS uses a silicon immersion grating as an echelle grating and VPH gratings are used as cross dispersers. IGRINS can observe the whole H- and K- bands in a single exposure and will have a resolving power of 40,000 with 0.68" entrance slit width at a 4m telescope. IGRINS will be placed initially on the McDonald 2.7m Harlan J. Smith telescope and later on 4-8m class telescopes. The calibration system will use Th-Ar hallow cathode lamp which is well known as a line emitting source at visible and near infrared and a tungsten halogen lamp in an integrating sphere to make a blackbody source for the flat-fielding. We also use OH emission lines and telluric absorption lines for line references and we are considering to adopt a gas absorption cell for the observation requiring more precise calibration using our high dispersion instrument. We are now optimizing the optical design for the calibration system to achieve 1% flatness of the flat-fielding source illumination over slit length and over the broad bands. We will soon design mechanical mounts for optical elements and sources, and moving parts.

  12. The SOAR integral field unit spectrograph optical design and IFU implementation

    NASA Astrophysics Data System (ADS)

    de Oliveira, A. C.; de Oliveira, L. S.; Gneiding, C. D.; Barbuy, B.; Jones, D.; Figueredo, M. V.; Lépine, J. R. D.; Macanhan, V. B. P.; Carvalho de Oliveira, J. B.; Taylor, K.

    2010-07-01

    SIFS is a lenslet/fiber Integral Field Unit Spectrograph which has just been delivered to the SOAR 4.1m telescope in Chile. The instrument was designed and constructed by the National Laboratory of Astrophysics (MCT/LNA) in collaboration with the Department of Astronomy of the Institute of Astronomy, Geophysics and Atmospheric Sciences of the University of Sao Paulo (IAG/USP). It is designed to operate at both the raw Nasmyth and the SAM (the SOAR Adaptive Optics Module) which delivers GLAO-corrected images in optical wave-bands longward of 500nm. The lenslets have a 1mm pitch feeding a set of 1,300 fibres in a 26-by-50 format. Sets of deployable fore-optics convert the f/16.5 input beam to give samplings between ~0.1 and 0.3 arcsec. The fiber output is in the form of a curved, pupil-centric, long-slit which is fed into a bench-mounted spectrograph. An off-axis Maksutov collimates the beam onto a set of VPH gratings and thence imaged by an f/3 refractive camera onto a 2-by-1 mosaic of 2k-by-4k E2V CCDs. The camera is articulated over a >90 deg. angle to allow the grating/camera combination to operate in a transmission Littrow configuration. The wavelength range is limited by the CCDs to the 350 to 1000nm range with spectral resolution maxima of ~20,000. The paper will review the optical design of the spectrograph and the methods used to fabricate the lenslet/fiber IFU.

  13. Integration of VIRUS spectrographs for the Hobby-Eberly Telescope Dark Energy Experiment

    NASA Astrophysics Data System (ADS)

    Heisler, J.; Mollison, N.; Soukup, I.; Hayes, R.; Hill, G. J.; Good, J.; Savage, R.; Vattiat, B.

    2010-07-01

    The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) at the University of Texas McDonald Observatory will deploy the Visible Integral-Field Replicable Unit Spectrograph (VIRUS) to survey large areas of sky. VIRUS consists of up to 192 spectrographs deployed as 96 units. VIRUS units are fiber-fed and are housed in four enclosures making up the VIRUS Support Structure (VSS). Initial design studies established an optimal array size and an upper and lower bound on their placement relative to the existing telescope structure. Tradeoffs considering IFU (optical fiber) length, support structure mass and ease of maintenance have resulted in placement of four 3 × 8 arrays of spectrograph pairs, about mid-point in elevation relative to the fixed HET structure. Because of the desire to minimize impact on the modal performance of the HET, the VSS is required to be an independent, selfsupporting structure and will only be coupled at the base of the telescope. Analysis shows that it is possible to utilize the existing azimuth drives of the telescope, through this coupling, which will greatly simplify the design and reduce cost. Each array is contained in an insulated enclosure that will control thermal load by means of heat exchangers and use of facility coolant supply. Access for installation and maintenance on the top, front, and rear of the enclosures must be provided. The design and analysis presented in this paper must provide an optimum balance in meeting the stringent requirements for science and facility constraints such as cost, weight, access, and safety.

  14. Comet 67P observations with LOTUS: a new near-UV spectrograph for the Liverpool Telescope

    NASA Astrophysics Data System (ADS)

    Marchant, Jon; Jermak, Helen; Steele, Iain; Snodgrass, Colin; Fitzsimmons, Alan; Jones, Geraint

    2015-11-01

    The European Space Agency’s Rosetta spacecraft has been orbiting comet 67P/Churyumov-Gerasimenko (hereinafter “67P”) since August 2014, providing in-situ measurements of the dust, gas and plasma content of the coma within ~100km of the nucleus. Supporting the mission is a world-wide coordinated campaign of simultaneous ground-based observations of 67P (www.rosetta-campaign.net), providing wider context of the outer coma and tail invisible to Rosetta. We can now compare these observations, augmented by "ground truth" from Rosetta, with those of other comets past and future that are only observed from Earth.The robotic Liverpool Telescope (LT) is part of this campaign due to its unique ability to flexibly and autonomously schedule regular observations over entire semesters. Its optical imagery has recently been supplemented by near-UV spectroscopy to observe the UV molecular bands below 4000Å that are of considerable interest to cometary science. The LT's existing spectrographs FRODOSpec and SPRAT cut off at 4000Å, so the Liverpool Telescope Optical-to-UV Spectrograph - LOTUS - was fast-track designed, built and deployed on-sky in just five months. LOTUS contains no moving parts; acquisition is made with the LT's IO:O imaging camera, and different width slits for calibration and science are selected by fine-tuning the telescope's pointing on an innovative "step" design in its single slit.We present here details of the LOTUS spectrograph, and some preliminary results of our ongoing observations of comet 67P.

  15. Performance of the Southern African Large Telescope (SALT) High Resolution Spectrograph (HRS)

    NASA Astrophysics Data System (ADS)

    Crause, Lisa A.; Sharples, Ray M.; Bramall, David G.; Schmoll, Jürgen; Clark, Paul; Younger, Eddy J.; Tyas, Luke M. G.; Ryan, Sean G.; Brink, Janus D.; Strydom, Ockert J.; Buckley, David A. H.; Wilkinson, Martin; Crawford, Steven M.; Depagne, Éric

    2014-07-01

    The Southern African Large Telescope (SALT) High Resolution Spectrograph (HRS) is a fibre-fed R4 échelle spectrograph employing a white pupil design with red and blue channels for wavelength coverage from 370-890nm. The instrument has four modes, each with object and sky fibres: Low (R~15000), Medium (R~40000) and High Resolution (R~65000), as well as a High Stability mode for enhanced radial velocity precision at R~65000. The High Stability mode contains a fibre double-scrambler and offers optional simultaneous Th-Ar arc injection, or the inclusion of an iodine cell in the beam. The LR mode has unsliced 500μm fibres and makes provision for nod-and-shuffle for improved background subtraction. The MR mode also uses 500μm fibres, while the HR and HS fibres are 350μm. The latter three modes employ modified Bowen-Walraven image-slicers to subdivide each fibre into three slices. All but the High Stability bench is sealed within a vacuum tank, which itself is enclosed in an interlocking Styrostone enclosure, to insulate the spectrograph against temperature and atmospheric pressure variations. The Fibre Instrument Feed (FIF) couples the four pairs of fibres to the telescope focal plane and allows the selection of the appropriate fibre pair for a given mode, and adjustment of the fibre separation to optimally position the sky fibre. The HRS employs a photomultiplier tube for an exposure meter and has a dedicated auto-guider attached to the FIF. We report here on the commissioning results and overall instrument performance since achieving first light on 28 September 2013.

  16. Performance Results from In-Flight Commissioning of the Juno Ultraviolet Spectrograph (Juno-UVS)

    NASA Astrophysics Data System (ADS)

    Greathouse, Thomas K.; Gladstone, G. R.; Davis, M. W.; Slater, D. C.; Versteeg, M. H.; Persson, K. B.; Winters, G. S.; Persyn, S. C.; Eterno, J. S.

    2012-10-01

    We present a description of the Juno ultraviolet spectrograph (Juno-UVS), results from the successful in-flight commissioning performed between December 5th and 13th 2011, and some predictions of future Jupiter observations. Juno-UVS is a modest power (9.0 W) ultraviolet spectrograph based on the Alice instruments now in flight aboard the European Space Agency’s Rosetta spacecraft, NASA’s New Horizons spacecraft, and the LAMP instrument aboard NASA’s Lunar Reconnaissance Orbiter. However, unlike the other Alice spectrographs, Juno-UVS sits aboard a rotationally stabilized spacecraft. The planned 2 rpm rotation rate for the primary mission results in integration times per spatial resolution element per spin of only 17 ms. Thus, data was retrieved from many spins and then remapped and co-added to build up integration times on bright stars to measure the effective area, spatial resolution, map out scan mirror pointing positions, etc. The Juno-UVS scan mirror allows for pointing of the slit approximately ±30° from the spacecraft spin plane. This ability gives Juno-UVS access to half the sky at any given spacecraft orientation. We will describe our process for solving for the pointing of the scan mirror relative to the Juno spacecraft and present our initial half sky survey of UV bright stars complete with constellation overlays. The primary job of Juno-UVS will be to characterize Jupiter’s UV auroral emissions and relate them to in situ particle measurements. The ability to point the slit will facilitate these measurements, allowing Juno-UVS to observe the surface positions of magnetic field lines Juno is flying through giving a direct connection between the particle measurements on the spacecraft to the observed reaction of Jupiter’s atmosphere to those particles. Finally, we will describe planned observations to be made during Earth flyby in October 2013 that will complete the in-flight characterization.

  17. Performance results from in-flight commissioning of the Juno Ultraviolet Spectrograph (Juno-UVS)

    NASA Astrophysics Data System (ADS)

    Greathouse, T. K.; Gladstone, G. R.; Davis, M. W.; Slater, D. C.; Versteeg, M. H.; Persson, K. B.; Walther, B. C.; Winters, G. S.; Persyn, S. C.; Eterno, J. S.

    2013-09-01

    We present a description of the Juno ultraviolet spectrograph (Juno-UVS) and results from its in-flight commissioning performed between December 5th and 13th 2011 and its first periodic maintenance between October 10th and 12th 2012. Juno-UVS is a modest power (9.0 W) ultraviolet spectrograph based on the Alice instruments now in flight aboard the European Space Agency's Rosetta spacecraft, NASA's New Horizons spacecraft, and the LAMP instrument aboard NASA's Lunar Reconnaissance Orbiter. However, unlike the other Alice spectrographs, Juno-UVS sits aboard a spin stabilized spacecraft. The Juno-UVS scan mirror allows for pointing of the slit approximately +/-30° from the spacecraft spin plane. This ability gives Juno-UVS access to half the sky at any given spacecraft orientation. The planned 2 rpm spin rate for the primary mission results in integration times per 0.2° spatial resolution element per spin of only ~17 ms. Thus, for calibration purposes, data were retrieved from many spins and then remapped and co-added to build up exposure times on bright stars to measure the effective area, spatial resolution, scan mirror pointing positions, etc. The primary job of Juno-UVS will be to characterize Jupiter's UV auroral emissions and relate them to in-situ particle measurements. The ability to point the slit will make operations more flexible, allowing Juno-UVS to observe the atmospheric footprints of magnetic field lines through which Juno flies, giving a direct connection between energetic particle measurements on the spacecraft and the far-ultraviolet emissions produced by Jupiter's atmosphere in response to those particles.

  18. Compact Circuit Preprocesses Accelerometer Output

    NASA Technical Reports Server (NTRS)

    Bozeman, Richard J., Jr.

    1993-01-01

    Compact electronic circuit transfers dc power to, and preprocesses ac output of, accelerometer and associated preamplifier. Incorporated into accelerometer case during initial fabrication or retrofit onto commercial accelerometer. Made of commercial integrated circuits and other conventional components; made smaller by use of micrologic and surface-mount technology.

  19. Generalized high order compact methods.

    SciTech Connect

    Spotz, William F.; Kominiarczuk, Jakub

    2010-09-01

    The fundamental ideas of the high order compact method are combined with the generalized finite difference method. The result is a finite difference method that works on unstructured, nonuniform grids, and is more accurate than one would classically expect from the number of grid points employed.

  20. Upwind Compact Finite Difference Schemes

    NASA Astrophysics Data System (ADS)

    Christie, I.

    1985-07-01

    It was shown by Ciment, Leventhal, and Weinberg ( J. Comput. Phys.28 (1978), 135) that the standard compact finite difference scheme may break down in convection dominated problems. An upwinding of the method, which maintains the fourth order accuracy, is suggested and favorable numerical results are found for a number of test problems.

  1. Mesoscale Simulations of Power Compaction

    SciTech Connect

    Lomov, I; Fujino, D; Antoun, T; Liu, B

    2009-08-06

    Mesoscale 3D simulations of metal and ceramic powder compaction in shock waves have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating shock compaction of porous well-characterized ductile metal using Steinberg material model. Results of the simulations with handbook values for parameters of solid 2024 aluminum have good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not so well studied as metals, so material model for ceramic (tungsten carbide) has been fitted to shock compression experiments of non-porous samples and further calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powder have been performed and showed good agreement with experimental data. Numerical shock wave profile has same character and thickness as measured with VISAR. Numerical results show reshock states above the single-shock Hugoniot line also observed in experiments. They found that to receive good quantitative agreement with experiment it is essential to perform 3D simulations.

  2. Mesoscale simulations of powder compaction

    NASA Astrophysics Data System (ADS)

    Lomov, Ilya; Antoun, Tarabay; Liu, Benjamin

    2009-06-01

    Mesoscale 3D simulations of metal and ceramic powder compaction in shock waves have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating shock compaction of porous well-characterized ductile metal using Steinberg material model. Results of the simulations with handbook values for parameters of solid 2024 aluminum have good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not so well studied as metals, so material model for ceramic (tungsten carbide) has been fitted to shock compression experiments of non-porous samples and further calibrated to experimental match compaction curves. Direct simulations of gas gun experiments with ceramic powder have been performed and showed good agreement with experimental data. Numerical shock wave profile has same character and thickness as measured with VISAR. Numerical results show evidence of hard-to-explain reshock states above the single-shock Hugoniot line, which have also been observed in the experiments. We found that to receive good quantitative agreement with experiment it is essential to perform 3D simulations, since 2D results tend to underpredict stress levels for high-porosity powders regardless of material properties. We developed a process to extract macroscale information for the simulation which can be directly used in calibration of continuum model for heterogeneous media.

  3. Properties of dynamically compacted WIPP salt

    SciTech Connect

    Brodsky, N.S.; Hansen, F.D.; Pfeifle, T.W.

    1996-07-01

    Dynamic compaction of mine-run salt is being investigated for the Waste Isolation Pilot Plant (WIPP), where compacted salt is being considered for repository sealing applications. One large-scale and two intermediate-scale dynamic compaction demonstrations were conducted. Initial fractional densities of the compacted salt range form 0.85 to 0.90, and permeabilities vary. Dynamically-compacted specimens were further consolidated in the laboratory by application of hydrostatic pressure. Permeability as a function of density was determined, and consolidation microprocesses were studied. Experimental results, in conjunction with modeling results, indicate that the compacted salt will function as a viable seal material.

  4. Detector Arrays for the James Webb Space Telescope Near-Infrared Spectrograph

    NASA Technical Reports Server (NTRS)

    Rauscher, Bernard J.; Alexander, David; Brambora, Clifford K.; Derro, Rebecca; Engler, Chuck; Fox, Ori; Garrison, Matthew B.; Henegar, Greg; Hill, robert J.; Johnson, Thomas; Lindler, Don J.; Manthripragada, Sridhar S.; Marshall, Ceryl; Mott, Brent; Parr, Thomas M.; Roher, Wayne D.; Shakoorzadeh, Kamdin B.; Smith, Miles; Waczynski, Augustyn; Wen, Yiting; Wilson, Donna; Xia-Serafino, Wei

    2007-01-01

    The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 micron cutoff (lambda(sub co) = 5 microns) 2048x2048 pixel Teledyne HgCdTe HAWAII-2RG sensor chip assemblies. These detector arrays, and the two Teledyne SIDECAR application specific integrated circuits that control them, are operated in space at T approx. 37 K. In this article, we provide a brief introduction to NIRSpec, its detector subsystem (DS), detector readout in the space radiation environment, and present a snapshot of the developmental status of the NIRSpec DS as integration and testing of the engineering test unit begins.

  5. Spectrographic phase-retrieval algorithm for femtosecond and attosecond pulses with frequency gaps

    NASA Astrophysics Data System (ADS)

    Seifert, B.; Wallentowitz, S.; Volkmann, U.; Hause, A.; Sperlich, K.; Stolz, H.

    2014-10-01

    We present a phase-reconstruction algorithm for a self-referenced spectrographic pulse characterization technique called “very advanced method for phase and intensity retrieval of e-fields” (VAMPIRE). This technique permits a spectral phase reconstruction of pulses with separated frequency components. The algorithm uses the particular characteristics of VAMPIRE spectrograms. It is a locally structured algorithm which is fast, robust, and it allows us to master stagnation problems. The algorithm is tested by use of both simulated and measured data.

  6. PEPSI, the High-Resolution Optical-IR Spectrograph for the LBT

    NASA Astrophysics Data System (ADS)

    Andersen, Michael; Strassmeier, Klaus; Hoffman, Axel; Woche, Manfred; Spano, Paolo

    PEPSI is a high resolution fibre feed optical-IR polarimetric echelle spectrograph for the Large Binocular Telescope (LBT). PEPSI utilizes the two 8.4m LBT apertures to simultaneously record four polarization states at a resolution of 120.000. The extension of the coverage towards the IR is mainly motivated by the larger Zeeman splitting of IR lines, which would allow to study weaker/fainter magnetic structures on stars. The two optical arms, which also have an integral light mode with R up to 300.000, are under construction, while the IR arm is being designed.

  7. The BUSS spectrum of Beta Lyrae. [Balloon-borne Ultraviolet Stellar Spectrograph

    NASA Technical Reports Server (NTRS)

    Hack, M.; Sahade, J.; De Jager, C.; Kondo, Y.

    1983-01-01

    The spectrum of Beta Lyrae from about 1975 to 3010 A taken with the Balloon-borne ultraviolet Stellar Spectrograph experiment in May 1976 at phase 0.61 P is analyzed. Results show the presence of N II semi-forbidden emission and provide evidence for about the same location, in the outer envelope of the system, of the layers responsible for the resonance Mg II doublet emissions and for the "narrow" H-alpha emission. In addition, three sets of absorption lines, P Cygni profiles of Fe III and broad Beals Type III emissions of Mg II, are found to be present.

  8. COSMIC ORIGINS SPECTROGRAPH OBSERVATIONS OF TRANSLUCENT CLOUDS: Cyg OB2 8A

    SciTech Connect

    Snow, Theodore P.; Destree, Joshua D.; Burgh, Eric B.; Ferguson, Ryan M.; Danforth, Charles W.; Cordiner, Martin E-mail: destree@colorado.ed E-mail: ryan.m.ferguson@colorado.ed E-mail: martin.cordiner@nasa.go

    2010-09-10

    Data from the Cosmic Origins Spectrograph (COS) are presented for the first highly reddened target (Cyg OB2 8A) under the COS Science Team's guaranteed time allocation. Column densities of ionic, atomic, and molecular species are reported and implications are discussed. Data from Cyg OB2 8A demonstrate the ability to analyze highly reddened interstellar sight lines with the COS that were unavailable to previous UV instruments. Measured column densities indicate that the Cyg OB2 8A line of sight contains multiple diffuse clouds rather than a dominant translucent cloud.

  9. Toward accurate radial velocities with the fiber-fed GIRAFFE multi-object VLT spectrograph

    NASA Astrophysics Data System (ADS)

    Royer, Frederic; Blecha, Andre; North, Pierre; Simond, Gilles; Baratchart, Sebastien; Cayatte, Veronique; Chemin, Laurent; Palsa, Ralf

    2002-12-01

    We describe briefly the Data-Reduction of the VLT fiber-fed multi-object GIRAFFE spectrograph - part of the VLT FLAMES facility. We focus on specific features of GIRAFFE - the simultaneous wavelength calibration - and their impact on the data-reduction strategy. We describe the implementation of the global physical model and we compare the results obtained with the simulated, laboratory and preliminary data. We discuss the influence of critical parameters, the overall accuracy of the wavelength solution, and the stability and the robustness of the global model approach. We address the accuracy of radial velocity measurements illustrated by solar spectra obtained during the Preliminary Acceptance in Europe.

  10. Spectrally resolved detection of sodium in the atmosphere of HD 189733b with the HARPS spectrograph

    NASA Astrophysics Data System (ADS)

    Wyttenbach, A.; Ehrenreich, D.; Lovis, C.; Udry, S.; Pepe, F.

    2015-05-01

    Context. Atmospheric properties of exoplanets can be constrained with transit spectroscopy. At low spectral resolution, this technique is limited by the presence of clouds. The signature of atomic sodium (Na i), known to be present above the clouds, is a powerful probe of the upper atmosphere, where it can be best detected and characterized at high spectral resolution. Aims: Our goal is to obtain a high-resolution transit spectrum of HD 189733b in the region around the resonance doublet of Na i at 589 nm, to characterize the absorption signature that was previously detected from space at low resolution. Methods: We analyzed archival transit data of HD 189733b obtained with the HARPS spectrograph (ℛ = 115 000) at the ESO 3.6-m telescope. We performed differential spectroscopy to retrieve the transit spectrum and light curve of the planet, implementing corrections for telluric contamination and planetary orbital motion. We compared our results to synthetic transit spectra calculated from isothermal models of the planetary atmosphere. Results: We spectrally resolve the Na i D doublet and measure line contrasts of 0.64 ± 0.07% (D2) and 0.40 ± 0.07% (D1) and FWHMs of 0.52 ± 0.08 Å. This corresponds to a detection at the 10σ level of excess of absorption of 0.32 ± 0.03% in a passband of 2 × 0.75 Å centered on each line. We derive temperatures of 2600 ± 600 K and 3270 ± 330 K at altitudes of 9800 ± 2800 and 12 700 ± 2600 km in the Na i D1 and D2 line cores, respectively. We measure a temperature gradient of ~0.2 K km-1 in the region where the sodium absorption dominates the haze absorption from a comparison with theoretical models. We also detect a blueshift of 0.16 ± 0.04 Å (4σ) in the line positions. This blueshift may be the result of winds blowing at 8 ± 2 km s-1 in the upper layers of the atmosphere. Conclusions: We demonstrate the relevance of studying exoplanet atmospheres with high-resolution spectrographs mounted on 4-m-class telescopes. Our

  11. The Addition of EI/CI Capability to the Mattauch-herzog Spectrograph with EOID

    NASA Technical Reports Server (NTRS)

    Fergusson, G. J.; Koslin, M. E.

    1979-01-01

    A modification was made to the Mattauch-Herzog Spectrograph with an electro-optical ion detector (EOID) previously designed and constructed, so that it would be capable of operating not only in the electron-impact (EI) mode of ionization, but also in the chemical ionization (CI) mode. This modification necessitated an effort in three specific design areas: (1) sample inlet; (2) ion source and analyzer regions; and (3) the pumping system. In addition, an appropriate electronics package had to be designed to control and operate the combined EI/CI source.

  12. MOSAIC: A Multi-Object Spectrograph for the E-ELT

    NASA Astrophysics Data System (ADS)

    Kelz, A.; Hammer, F.; Jagourel, P.; MOSAIC Consortium

    2016-10-01

    The instrumentation plan for the European Extremely Large Telescope foresees a Multi-Object Spectrograph (E-ELT MOS). The MOSAIC project is proposed by a European-Brazilian consortium, to provide a unique MOS facility for astrophysics, studies of the inter-galactic medium and for cosmology. The science cases range from spectroscopy of the most distant galaxies, mass assembly and evolution of galaxies, via resolved stellar populations and galactic archaeology, to planet formation studies. A further strong driver is spectroscopic follow-up observations of targets that will be discovered with the James Webb Space Telescope.

  13. Deep-depletion Hamamatsu CCDs for the Gemini multi-object spectrograph

    NASA Astrophysics Data System (ADS)

    Hardy, Tim; Hanna, Kevin; Szeto, Kei; Burley, Greg

    2012-07-01

    The instrumentation group of the Herzberg Institute of Astrophysics was commissioned by the Gemini Observatory to develop a new focal plane assembly for the Gemini Multi-Object Spectrograph with an array of three deep-depletion Hamamatsu CCDs. The main objective of the upgrade is to improve the sensitivity of the instrument in the red and nearinfrared wavelengths, with the additional benefits of reduced fringing, faster readout, and better performance in the "nod and shuffle" mode. We describe what we learned about these relatively new CCDs, including several problems encountered during testing, and report on the performance of the system.

  14. High-resolution fibre-fed spectrograph for the 6-m telescope. Polarimetric unit

    NASA Astrophysics Data System (ADS)

    Kukushkin, D. E.; Sazonenko, D. A.; Bakholdin, A. V.; Yushkin, M. V.; Bychkov, V. D.

    2016-04-01

    We report the computation of the design of a polarimetric unit for the optical scheme of the fiberfed high-resolution spectrograph for the 6-m Russian telescope.We discuss a variant of its integration into the design of conversion optics at the input of the fiber path if the instrument and estimate the efficiency of the entire pre-fiber optical system. The luminous efficiency of the assembly is equal to 80 and 90% when operated in the polarimetry and normal spectroscopic modes, respectively.We estimate the lower limit for the distorting instrumental effects of the polarimetric unit.

  15. The control unit of the near infrared spectrograph of the EUCLID space mission: preliminary design

    NASA Astrophysics Data System (ADS)

    Toledo-Moreo, Rafael; Colodro-Conde, Carlos; Díaz-García, José Javier; Tubío-Araujo, Óscar Manuel; Gómez-Sáenz, Jaime; Peña-Godino, Antonio; Velasco-Fernández, Tirso; Sánchez-Prieto, Sebastián.; Villó-Pérez, Isidro; Rebolo-López, Rafael

    2014-08-01

    The Near Infrared Spectrograph and Photometer (NISP) is one of the instruments on board the ESA EUCLID mission. The Universidad Politecnica de Cartagena and Instituto de Astrofisica de Canarias are responsible of the Instrument Control Unit of the NISP (NI-ICU) in the Euclid Consortium. The NI-ICU main functions are: communication with the S/C and the Data Processing Unit, control of the Filter and Grism Wheels, control of the Calibration Unit and thermal control of the instrument. This paper presents the NI-ICU status of definition and design at the end of the preliminary design phase.

  16. Apollo 16 far-ultraviolet camera/spectrograph - Instrument and operations.

    NASA Technical Reports Server (NTRS)

    Carruthers, G. R.

    1973-01-01

    A far-ultraviolet camera/spectrograph experiment was designed and constructed for studies of the terrestrial upper atmosphere and geocorona, the interplanetary medium, and celestial objects from the lunar surface. The experiment was successfully operated during the Apollo 16 mission 21-23 April 1972. Discussed are the design and operating principles of the instrument, the actual events and operations during the Apollo 16 mission, and also anomalies encountered and suggested improvements for future experiments of this type. This experiment demonstrated the utility of the electronographic technique in space astronomy, as well as the great potential of the lunar surface as a base for astronomical observations.

  17. Juno Ultraviolet Spectrograph (Juno-UVS) Observations of Jupiter during Approach

    NASA Astrophysics Data System (ADS)

    Gladstone, Randy; Versteeg, Maarten; Greathouse, Thomas K.; Hue, Vincent; Davis, Michael; Gerard, Jean-Claude; Grodent, Denis; Bonfond, Bertrand

    2016-10-01

    We present the initial results from Juno Ultraviolet Spectrograph (Juno-UVS) observations of Jupiter obtained during approach in June 2016. Juno-UVS is an imaging spectrograph with a bandpass of 70<λ<205 nm. This wavelength range includes all important ultraviolet (UV) emissions from the H2 bands and the H Lyman series which are produced in Jupiter's auroras, and also the absorption signatures of aurorally-produced hydrocarbons. The Juno-UVS instrument telescope has a 4 x 4 cm2 input aperture and uses an off-axis parabolic primary mirror. A flat scan mirror situated near the entrance of the telescope is used to observe at up to ±30° perpendicular to the Juno spin plane. The light is focused onto the spectrograph entrance slit, which has a "dog-bone" shape 7.2° long, in three sections of 0.2°, 0.025°, and 0.2° width (as projected onto the sky). Light entering the slit is dispersed by a toroidal grating which focuses UV light onto a curved microchannel plate (MCP) cross delay line (XDL) detector with a solar blind UV-sensitive CsI photocathode. Tantalum surrounds the spectrograph assembly to shield the detector and its electronics from high-energy electrons. All other electronics are located in Juno's spacecraft vault, including redundant low-voltage and high-voltage power supplies, command and data handling electronics, heater/actuator electronics, scan mirror electronics, and event processing electronics. The purpose of Juno-UVS is to remotely sense Jupiter's auroral morphology and brightness to provide context for in situ measurements by Juno's particle instruments. Prior to Jupiter Orbit Insertion (JOI) on July 5, Juno approach observations provide a rare opportunity to correlate local solar wind conditions with Jovian auroral emissions. Some of Jupiter's auroral emissions (e.g., polar emissions) may be controlled or at least affected by the solar wind. Here we compare synoptic Juno-UVS observations of Jupiter's auroral emissions (~40 minutes per hour

  18. The opto-mechanical design of the Colorado High-resolution Echelle Stellar Spectrograph (CHESS)

    NASA Astrophysics Data System (ADS)

    Kane, Robert; Beasley, Matthew; Green, James; Burgh, Eric; France, Kevin

    2011-09-01

    We present the Colorado High-resolution Echelle Stellar Spectrograph (CHESS) sounding rocket payload. The design uses a mechanical collimator made from a grid of square tubing, an objective echelle grating, a holographically-ruled cross-disperser, a new 40 mm MCP with a cross strip anode or a delta-doped 3.5k x 3.5k CCD detector. The optics are suspended using carbon fiber rods epoxied to titanium inserts to create a space frame structure. A preliminary design is presented.

  19. The new Teledyne NIR detectors for the SNAP/JDEM mission spectrograph

    NASA Astrophysics Data System (ADS)

    Crouzet, P. E.

    2009-10-01

    A new generation of near infrared (NIR) detectors have been developed by Teledyne for the SNAP/JDEM (SuperNova/Acceleration Probe) project. The new detectors are hybridized HgCdTe on a multiplexer with indium bump bonded. Since 2004, Teledyne and the SNAP collaboration have tried to characterize and improve the large format (2k×2k) H2RG detectors to meet the SNAP requirements. The results for quantum efficiency and total noise as an integration of a H2RG in a spectrograph demonstrator are presented.

  20. Grazing-incidence high-resolution stigmatic spectrograph with two optical elements.

    PubMed

    Malvezzi, A M; Garifo, L; Tondello, G

    1981-07-15

    Using two optical toroidal elements, a mirror and a grating, both working at grazing incidence, a spectrometer can be built that is stigmatic in the XUV region at one wavelength. Good compensation of the aberrations is achieved when the intermediate sagittal image is nearly at infinity. By varying the angle of incidence on the grating with simple movements, a given couple of optical elements could cover stigmatically a rather extended spectral range. If coupled with bidimensional array detectors, such a spectrograph could find applications in planned solar XUV telescopes.

  1. Remote sensing of seawater and drifting ice in Svalbard fjords by compact Raman lidar.

    PubMed

    Bunkin, Alexey F; Klinkov, Vladimir K; Lednev, Vasily N; Lushnikov, Dmitry L; Marchenko, Aleksey V; Morozov, Eugene G; Pershin, Sergey M; Yulmetov, Renat N

    2012-08-01

    A compact Raman lidar system for remote sensing of sea and drifting ice was developed at the Wave Research Center at the Prokhorov General Physics Institute of the Russian Academy of Sciences. The developed system is based on a diode-pumped solid-state YVO(4):Nd laser combined with a compact spectrograph equipped with a gated detector. The system exhibits high sensitivity and can be used for mapping or depth profiling of different parameters within many oceanographic problems. Light weight (∼20 kg) and low power consumption (300 W) make it possible to install the device on any vehicle, including unmanned aircraft or submarine systems. The Raman lidar presented was used for study and analysis of the different influence of the open sea and glaciers on water properties in Svalbard fjords. Temperature, phytoplankton, and dissolved organic matter distributions in the seawater were studied in the Ice Fjord, Van Mijen Fjord, and Rinders Fjord. Drifting ice and seawater in the Rinders Fjord were characterized by the Raman spectroscopy and fluorescence. It was found that the Paula Glacier strongly influences the water temperature and chlorophyll distributions in the Van Mijen Fjord and Rinders Fjord. Possible applications of compact lidar systems for express monitoring of seawater in places with high concentrations of floating ice or near cold streams in the Arctic Ocean are discussed. PMID:22859038

  2. A compact and portable laser-induced breakdown spectroscopy instrument for single and double pulse applications

    NASA Astrophysics Data System (ADS)

    Goujon, J.; Giakoumaki, A.; Piñon, V.; Musset, O.; Anglos, D.; Georgiou, E.; Boquillon, J. P.

    2008-10-01

    We present LIBS experimental results that demonstrate the use of a newly developed, compact, versatile pulsed laser source in material analysis related to art and archaeological applications in view of research aiming at the development of portable LIBS instrumentation. LIBS qualitative analysis measurements were performed on various samples and objects, and the spectra were recorded in gated and non-gated modes. The latter is important because of advantages arising from size and cost reduction when using simple, compact spectrograph-CCD detection systems over the standard ICCD-based configurations. The new laser source exhibited a very reliable performance in terms of laser pulse repeatability, autonomy and interface. Having the ability to work in double pulse mode it provided versatility in the measurements leading to increased LIBS signal intensities, improved the signal-to-noise ratio and the RSD of the spectra. The first test results are encouraging and demonstrate that this new laser is suitable for integration in compact, portable LIBS sensors with a wide spectrum of materials analysis applications.

  3. Remote sensing of seawater and drifting ice in Svalbard fjords by compact Raman lidar.

    PubMed

    Bunkin, Alexey F; Klinkov, Vladimir K; Lednev, Vasily N; Lushnikov, Dmitry L; Marchenko, Aleksey V; Morozov, Eugene G; Pershin, Sergey M; Yulmetov, Renat N

    2012-08-01

    A compact Raman lidar system for remote sensing of sea and drifting ice was developed at the Wave Research Center at the Prokhorov General Physics Institute of the Russian Academy of Sciences. The developed system is based on a diode-pumped solid-state YVO(4):Nd laser combined with a compact spectrograph equipped with a gated detector. The system exhibits high sensitivity and can be used for mapping or depth profiling of different parameters within many oceanographic problems. Light weight (∼20 kg) and low power consumption (300 W) make it possible to install the device on any vehicle, including unmanned aircraft or submarine systems. The Raman lidar presented was used for study and analysis of the different influence of the open sea and glaciers on water properties in Svalbard fjords. Temperature, phytoplankton, and dissolved organic matter distributions in the seawater were studied in the Ice Fjord, Van Mijen Fjord, and Rinders Fjord. Drifting ice and seawater in the Rinders Fjord were characterized by the Raman spectroscopy and fluorescence. It was found that the Paula Glacier strongly influences the water temperature and chlorophyll distributions in the Van Mijen Fjord and Rinders Fjord. Possible applications of compact lidar systems for express monitoring of seawater in places with high concentrations of floating ice or near cold streams in the Arctic Ocean are discussed.

  4. MID-INFRARED PROPERTIES OF NEARBY LUMINOUS INFRARED GALAXIES. I. SPITZER INFRARED SPECTROGRAPH SPECTRA FOR THE GOALS SAMPLE

    SciTech Connect

    Stierwalt, S.; Armus, L.; Surace, J. A.; Inami, H.; Petric, A. O.; Diaz-Santos, T.; Haan, S.; Howell, J.; Marshall, J.; Charmandaris, V.; Kim, D. C.; Mazzarella, J. M.; Chan, B.; Spoon, H. W. W.; Veilleux, S.; Evans, A.; Sanders, D. B.; Appleton, P.; Bothun, G.; Bridge, C. R.; and others

    2013-05-01

    The Great Observatories All-Sky LIRG Survey (GOALS) is a comprehensive, multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here we present low resolution Spitzer Infrared Spectrograph spectra covering 5-38 {mu}m and provide a basic analysis of the mid-IR spectral properties observed for nearby LIRGs. In a companion paper, we discuss detailed fits to the spectra and compare the LIRGs to other classes of galaxies. The GOALS sample of 244 nuclei in 180 luminous (10{sup 11} {<=} L {sub IR}/L {sub Sun} < 10{sup 12}) and 22 ultraluminous (L {sub IR}/L {sub Sun} {>=} 10{sup 12}) IR galaxies represents a complete subset of the IRAS Revised Bright Galaxy Sample and covers a range of merger stages, morphologies, and spectral types. The majority (>60%) of the GOALS LIRGs have high 6.2 {mu}m polycyclic aromatic hydrocarbon (PAH) equivalent widths (EQW{sub 6.2{mu}m} > 0.4 {mu}m) and low levels of silicate absorption (s {sub 9.7{mu}m} > -1.0). There is a general trend among the U/LIRGs for both silicate depth and mid-infrared (MIR) slope to increase with increasing L {sub IR}. U/LIRGs in the late to final stages of a merger also have, on average, steeper MIR slopes and higher levels of dust obscuration. Together, these trends suggest that as gas and dust is funneled toward the center of a coalescing merger, the nuclei become more compact and more obscured. As a result, the dust temperature increases also leading to a steeper MIR slope. The sources that depart from these correlations have very low PAH equivalent width (EQW{sub 6.2{mu}m} < 0.1 {mu}m) consistent with their emission being dominated by an active galactic nucleus (AGN) in the MIR. These extremely low PAH EQW sources separate into two distinct types: relatively unobscured sources with a very hot dust component (and thus very shallow MIR slopes) and heavily dust obscured nuclei with a steep temperature gradient. The most heavily dust obscured sources are also the most compact in their MIR

  5. Development of a cryogenic system for the VIRUS array of 150 spectrographs for the Hobby-Eberly Telescope

    NASA Astrophysics Data System (ADS)

    Chonis, Taylor S.; Vattiat, Brian L.; Hill, Gary J.; Marshall, J. L.; Cabral, Kris; DePoy, D. L.; Smith, Michael P.; Good, John M.; Booth, John A.; Rafal, Marc D.; Savage, Richard D.

    2010-07-01

    The upcoming Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) has provided motivation for upgrading the Hobby-Eberly Telescope (HET) at the McDonald Observatory. This upgrade includes an increase in the field-of-view to accommodate the new and revolutionary Visible Integral-field Replicable Unit Spectrograph (VIRUS). VIRUS is the instrument designed to conduct the HETDEX survey and consists of 150 individual integral-field spectrographs fed by 33,600 total optical fibers covering the 22 arc-minute field-of-view of the upgraded HET. The spectrographs are mounted in four enclosures, each 6.0×3.0×1.4 meters in size. Each spectrograph contains a CCD detector that must be cryogenically cooled, presenting an interesting cryogenic and vacuum challenge within the distribution system. In this paper, we review the proposed vacuum jacketed, thermal siphon, liquid nitrogen distribution system used to cool the array of detectors and discuss recent developments. We focus on the design, prototyping, and testing of a novel "make-break" thermal connector, built from a modified cryogenic bayonet, that is used to quickly detach a single spectrograph pair from the system.

  6. Introducing CUBES: the Cassegrain U-band Brazil-ESO spectrograph

    NASA Astrophysics Data System (ADS)

    Bristow, Paul; Barbuy, Beatriz; Macanhan, Vanessa B.; Castilho, Bruno; Dekker, Hans; Delabre, Bernard; Diaz, Marcos; Gneiding, Clemens; Kerber, Florian; Kuntschner, Harald; La Mura, Giovanni; Reiss, Roland; Vernet, J.

    2014-07-01

    CUBES is a high-efficiency, medium-resolution (R ≃ 20, 000) spectrograph dedicated to the "ground based UV" (approximately the wavelength range from 300 to 400nm) destined for the Cassegrain focus of one of ESO's VLT unit telescopes in 2018/19. The CUBES project is a joint venture between ESO and Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG) at the Universidade de São Paulo and the Brazilian Laboratório Nacional de Astrofísica (LNA). CUBES will provide access to a wealth of new and relevant information for stellar as well as extra-galactic sources. Principle science cases include the study of heavy elements in metal-poor stars, the direct determination of carbon, nitrogen and oxygen abundances by study of molecular bands in the UV range and the determination of the Beryllium abundance as well as the study of active galactic nuclei and the inter-galactic medium. With a streamlined modern instrument design, high efficiency dispersing elements and UV-sensitive detectors, it will enable a significant gain in sensitivity over existing ground based medium-high resolution spectrographs enabling vastly increased sample sizes accessible to the astronomical community. We present here a brief overview of the project, introducing the science cases that drive the design and discussing the design options and technological challenges.

  7. Conceptual Design of the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) for the Subaru Telescope

    NASA Technical Reports Server (NTRS)

    Peters, Mary Anne; Groff, Tyler; Kasdin, N. Jeremy; McElwain, Michael W.; Galvin, Michael; Carr, Michael A.; Lupton, Robert; Gunn, James E.; Knapp, Gillian; Gong, Qian; Carlotti, Alexis; Brandt, Timothy; Janson, Markus; Guyon, Olivier; Martinache, Frantz; Hayashi, Masahiko; Takato, Naruhisa

    2012-01-01

    Recent developments in high-contrast imaging techniques now make possible both imaging and spectroscopy of planets around nearby stars. We present the conceptual design of the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS), a lenslet-based, cryogenic integral field spectrograph (IFS) for imaging exoplanets on the Subaru telescope. The IFS will provide spectral information for 140 x 140 spatial elements over a 1.75 arcsecs x 1.75 arcsecs field of view (FOV). CHARIS will operate in the near infrared (lambda = 0.9 - 2.5 micron) and provide a spectral resolution of R = 14, 33, and 65 in three separate observing modes. Taking advantage of the adaptive optics systems and advanced coronagraphs (AO188 and SCExAO) on the Subaru telescope, CHARIS will provide sufficient contrast to obtain spectra of young self-luminous Jupiter-mass exoplanets. CHARIS is in the early design phases and is projected to have first light by the end of 2015. We report here on the current conceptual design of CHARIS and the design challenges.

  8. Compatibility of Spatially Coded Apertures with a Miniature Mattauch-Herzog Mass Spectrograph

    NASA Astrophysics Data System (ADS)

    Russell, Zachary E.; DiDona, Shane T.; Amsden, Jason J.; Parker, Charles B.; Kibelka, Gottfried; Gehm, Michael E.; Glass, Jeffrey T.

    2016-04-01

    In order to minimize losses in signal intensity often present in mass spectrometry miniaturization efforts, we recently applied the principles of spatially coded apertures to magnetic sector mass spectrometry, thereby achieving increases in signal intensity of greater than 10× with no loss in mass resolution Chen et al. (J. Am. Soc. Mass Spectrom. 26, 1633-1640, 2015), Russell et al. (J. Am. Soc. Mass Spectrom. 26, 248-256, 2015). In this work, we simulate theoretical compatibility and demonstrate preliminary experimental compatibility of the Mattauch-Herzog mass spectrograph geometry with spatial coding. For the simulation-based theoretical assessment, COMSOL Multiphysics finite element solvers were used to simulate electric and magnetic fields, and a custom particle tracing routine was written in C# that allowed for calculations of more than 15 million particle trajectory time steps per second. Preliminary experimental results demonstrating compatibility of spatial coding with the Mattauch-Herzog geometry were obtained using a commercial miniature mass spectrograph from OI Analytical/Xylem.

  9. Line profile analysis of an astronomical spectrograph with a laser frequency comb

    NASA Astrophysics Data System (ADS)

    Zhao, Fei; Zhao, Gang; Lo Curto, Gaspare; Wang, Hui-Juan; Liu, Yu-Juan; Wang, Liang; Wang, Wei

    2014-08-01

    We present a study of the spectral line shape associated with a High Resolution Spectrograph on the 2.16 m telescope at the Xinglong Observing Station of National Astronomical Observatories, Chinese Academy of Sciences. This measurement is based on modeling the instrumental line shape obtained by unresolved modes from a Yb-fiber mode-locked laser frequency comb. With the current repetition rate of 250 MHz and 26 GHz mode spacing on the spectrograph, we find the absolute variation of the line center, 0.0597 pixel in the direction of the CCDs, and 0.00275 pixel (~3 m s-1) for relative variation in successive exposures on a short timescale. A novel double-Gaussian model is presented to improve the quality of the fit by a factor of 2.47 in a typical single exposure. We also use analysis with raw moments and central moments to characterize the change in line shape across the detector. A trend in charge transfer efficiency can be found on the E2V 4096 × 4096 CCD that provides a correction for wavelength calibration aiming to reach a level of precision for radial velocity below 1 ms-1.

  10. UVSTAR: An imaging spectrograph with telescope for the Shuttle Hitchhiker-M platform

    NASA Technical Reports Server (NTRS)

    Stalio, Roberto; Sandel, Bill R.; Broadfoot, A. Lyle

    1993-01-01

    UVSTAR is an EUV spectral imager intended as a facility instrument devoted to solar system and astronomy studies. It covers the wavelength range of 500 to 1250 A, with sufficient spectral resolution to separate emission lines and to form spectrally resolved images of extended plasma sources. Targets include the Io plasma torus at Jupiter, hot stars, planetary nebulae and bright galaxies. UVSTAR consists of a pair of telescopes and concave grating spectrographs that cover the overlapping spectral ranges of 500-900 and 850-1250 A. The telescopes use two 30 cm diameter off-axis paraboloids having focal length of 1.5 m. An image of the target is formed at the entrance slits of the two concave grating spectrographs. The gratings provide dispersion and re-image the slits at the detectors, intensified CCD's. The readout format of the detectors can be chosen by computer, and three slit widths are selectable to adapt the instrument to specific tasks. UVSTAR has internal gimbals which allow rotation of plus or minus 3 deg about each of two axes. Dedicated finding and tracking telescopes will acquire and track the target after rough pointing is achieved by orienting the Orbiter. Responsibilities for implementation and utilization of UVSTAR are shared by groups in Italy and the U.S. UVSTAR is scheduled for flight in early 1995, timed for an opportunity to observe the Jovian system.

  11. Observations of Outflowing Ultraviolet Absorbers in NGC 4051 with the Cosmic Origins Spectrograph

    NASA Astrophysics Data System (ADS)

    Kraemer, S. B.; Crenshaw, D. M.; Dunn, J. P.; Turner, T. J.; Lobban, A. P.; Miller, L.; Reeves, J. N.; Fischer, T. C.; Braito, V.

    2012-06-01

    We present new Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) observations of the narrow-line Seyfert 1 galaxy NGC 4051. These data were obtained as part of a coordinated observing program including X-ray observations with the Chandra/High Energy Transmission Grating (HETG) spectrometer and Suzaku. We detected nine kinematic components of UV absorption, which were previously identified using the HST/Space Telescope Imaging Spectrograph (STIS). None of the absorption components showed evidence for changes in column density or profile within the ~10 yr between the STIS and COS observations, which we interpret as evidence of (1) saturation, for the stronger components, or (2) very low densities, i.e., n H < 1 cm-3, for the weaker components. After applying a +200 km s-1 offset to the HETG spectrum, we found that the radial velocities of the UV absorbers lay within the O VII profile. Based on photoionization models, we suggest that, while UV components 2, 5, and 7 produce significant O VII absorption, the bulk of the X-ray absorption detected in the HETG analysis occurs in more highly ionized gas. Moreover, the mass-loss rate is dominated by high-ionization gas which lacks a significant UV footprint. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposal 11834.

  12. OBSERVATIONS OF OUTFLOWING ULTRAVIOLET ABSORBERS IN NGC 4051 WITH THE COSMIC ORIGINS SPECTROGRAPH

    SciTech Connect

    Kraemer, S. B.; Crenshaw, D. M.; Fischer, T. C.; Dunn, J. P.; Turner, T. J.; Lobban, A. P.; Reeves, J. N.; Miller, L.; Braito, V.

    2012-06-01

    We present new Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) observations of the narrow-line Seyfert 1 galaxy NGC 4051. These data were obtained as part of a coordinated observing program including X-ray observations with the Chandra/High Energy Transmission Grating (HETG) spectrometer and Suzaku. We detected nine kinematic components of UV absorption, which were previously identified using the HST/Space Telescope Imaging Spectrograph (STIS). None of the absorption components showed evidence for changes in column density or profile within the {approx}10 yr between the STIS and COS observations, which we interpret as evidence of (1) saturation, for the stronger components, or (2) very low densities, i.e., n{sub H} < 1 cm{sup -3}, for the weaker components. After applying a +200 km s{sup -1} offset to the HETG spectrum, we found that the radial velocities of the UV absorbers lay within the O VII profile. Based on photoionization models, we suggest that, while UV components 2, 5, and 7 produce significant O VII absorption, the bulk of the X-ray absorption detected in the HETG analysis occurs in more highly ionized gas. Moreover, the mass-loss rate is dominated by high-ionization gas which lacks a significant UV footprint.

  13. MuSICa: the Multi-Slit Image Slicer for the est Spectrograph

    NASA Astrophysics Data System (ADS)

    Calcines, A.; López, R. L.; Collados, M.

    2013-09-01

    Integral field spectroscopy (IFS) is a technique that allows one to obtain the spectra of all the points of a bidimensional field of view simultaneously. It is being applied to the new generation of the largest night-time telescopes but it is also an innovative technique for solar physics. This paper presents the design of a new image slicer, MuSICa (Multi-Slit Image slicer based on collimator-Camera), for the integral field spectrograph of the 4-m aperture European Solar Telescope (EST). MuSICa is a multi-slit image slicer that decomposes an 80 arcsec2 field of view into slices of 50 μm and reorganizes it into eight slits of 0.05 arcsec width × 200 arcsec length. It is a telecentric system with an optical quality at diffraction limit compatible with the two modes of operation of the spectrograph: spectroscopic and spectro-polarimetric. This paper shows the requirements, technical characteristics and layout of MuSICa, as well as other studied design options.

  14. The Fiber Multi-object Spectrograph (FMOS) Project: the Anglo-Australian Observatory role

    NASA Astrophysics Data System (ADS)

    Gillingham, Peter R.; Moore, Anna M.; Akiyama, Masayuki; Brzeski, Jurek; Correll, David; Dawson, John; Farrell, Tony J.; Frost, Gabriella; Griesbach, Jason S.; Haynes, Roger; Jones, Damien; Miziarski, Stan; Muller, Rolf; Smedley, Scott; Smith, Greg; Waller, Lew G.; Noakes, Katie; Arridge, Chris

    2003-03-01

    The Fiber Multi-Object Spectrograph (FMOS) project is an Australia-Japan-UK collaboration to design and build a novel 400 fiber positioner feeding two near infrared spectrographs from the prime focus of the Subaru telescope. The project comprises several parts. Those under design and construction at the Anglo-Australian Observatory (AAO) are the piezoelectric actuator driven fiber positioner (Echidna), a wide field (30 arcmin) corrector and a focal plane imager (FPI) used for controlling the positioner and for field acquisition. This paper presents an overview of the AAO share of the FMOS project. It describes the technical infrastructure required to extend the single Echidna "spine" design to a fully functioning multi-fiber instrument, capable of complete field reconfiguration in less than ten minutes. The modular Echidna system is introduced, wherein the field of view is populated by 12 identical rectangular modules, each positioning 40 science fibers and 2 guide fiber bundles. This arrangement allows maintenance by exchanging modules and minimizes the difficulties of construction. The associated electronics hardware, in itself a significant challenge, includes a 23 layer PCB board, able to supply current to each piezoelectric element in the module. The FPI is a dual purpose imaging system translating in two coordinates and is located beneath the assembled modules. The FPI measures the spine positions as well as acquiring sky images for instrument calibration and for field acquisition. An overview of the software is included.

  15. Compatibility of Spatially Coded Apertures with a Miniature Mattauch-Herzog Mass Spectrograph.

    PubMed

    Russell, Zachary E; DiDona, Shane T; Amsden, Jason J; Parker, Charles B; Kibelka, Gottfried; Gehm, Michael E; Glass, Jeffrey T

    2016-04-01

    In order to minimize losses in signal intensity often present in mass spectrometry miniaturization efforts, we recently applied the principles of spatially coded apertures to magnetic sector mass spectrometry, thereby achieving increases in signal intensity of greater than 10× with no loss in mass resolution Chen et al. (J. Am. Soc. Mass Spectrom. 26, 1633-1640, 2015), Russell et al. (J. Am. Soc. Mass Spectrom. 26, 248-256, 2015). In this work, we simulate theoretical compatibility and demonstrate preliminary experimental compatibility of the Mattauch-Herzog mass spectrograph geometry with spatial coding. For the simulation-based theoretical assessment, COMSOL Multiphysics finite element solvers were used to simulate electric and magnetic fields, and a custom particle tracing routine was written in C# that allowed for calculations of more than 15 million particle trajectory time steps per second. Preliminary experimental results demonstrating compatibility of spatial coding with the Mattauch-Herzog geometry were obtained using a commercial miniature mass spectrograph from OI Analytical/Xylem. PMID:26744293

  16. Development of a slicer integral field unit for the existing optical spectrograph FOCAS: progress

    NASA Astrophysics Data System (ADS)

    Ozaki, Shinobu; Tanaka, Yoko; Hattori, Takashi; Mitsui, Kenji; Fukushima, Mitsuhiro; Okada, Norio; Obuchi, Yoshiyuki; Tsuzuki, Toshihiro; Miyazaki, Satoshi; Yamashita, Takuya

    2014-07-01

    We are developing an integral field unit (IFU) with an image slicer for the existing optical spectrograph, Faint Object Camera And Spectrograph (FOCAS), on the Subaru Telescope. The slice width is 0.43 arcsec, the slice number is 23, and the field of view is 13.5 × 9.89 arcsec2. Sky spectrum separated by about 5.7 arcmin from an object field can be simultaneously obtained, which allows us precise background subtraction. Slice mirrors, pupil mirrors and slit mirrors are all glass, and their mirror surfaces are fabricated by polishing. Our IFU is about 200 mm × 300 mm × 80 mm in size and 1 kg in weight. It is installed into a mask storage in FOCAS along with one or two mask plates, and inserted into the optical path by using the existing mask exchange mechanism. This concept allow us flexible operation such as Targets of Opportunity observations. High reflectivity of multilayer dielectric coatings offers high throughput (>80%) of the IFU. In this paper, we will report a final optical layout, its performances, and results of prototyping works.

  17. Exploring variations in the fundamental constants with ELTs: the CODEX spectrograph on OWL

    NASA Astrophysics Data System (ADS)

    Molaro, Paolo; Murphy, Michael T.; Levshakov, Sergei A.

    Cosmological variations in the fine structure constant, α, can be probed through precise velocity measurements of metallic absorption lines from intervening gas clouds seen in spectra of distant quasars. Data from the Keck/HIRES instrument support a variation in α of 6 parts per million. Such a variation would have profound implications, possibly providing a window into the extra spatial dimensions required by unified theories such as string/M-theory. However, recent results from VLT/UVES suggest no variation in α. The COsmic Dynamics EXperiment (CODEX) spectrograph currently being designed for the ESO OWL telescope (Pasquini et al. 2005) with a resolution high enough to properly resolve even the narrowest of metallic absorption lines, R > 150000, will achieve a 2-to-3 order-of-magnitude precision increase in Δα/α. This will rival the precision available from the Oklo natural fission reactor and upcoming satellite-borne atomic clock experiments. Given the vital constraints on fundamental physics possible, the ELT community must consider such a high-resolution optical spectrograph like CODEX.

  18. ALICE: The Ultraviolet Imaging Spectrograph Aboard the New Horizons Pluto-Kuiper Belt Mission

    NASA Astrophysics Data System (ADS)

    Stern, S. Alan; Slater, David C.; Scherrer, John; Stone, John; Dirks, Greg; Versteeg, Maarten; Davis, Michael; Gladstone, G. Randall; Parker, Joel W.; Young, Leslie A.; Siegmund, Oswald H. W.

    2008-10-01

    The ALICE instrument is a lightweight (4.4 kg), low-power (4.4 watt) imaging spectrograph aboard the New Horizons mission to the Pluto system and the Kuiper Belt. Its primary job is to determine the relative abundances of various species in Pluto’s atmosphere. ALICE will also be used to search for an atmosphere around Pluto’s moon, Charon, as well as the Kuiper Belt Objects (KBOs) that New Horizons is expected to fly by after Pluto-Charon, and it will make UV surface reflectivity measurements of all of these bodies, as well as of Pluto’s smaller moons Nix and Hydra. The instrument incorporates an off-axis telescope feeding a Rowland-circle spectrograph with a 520-1870 Å spectral passband, a spectral point spread function of 3-6 Å FWHM, and an instantaneous spatial field-of-view that is 6 degrees long. Two different input apertures that feed the telescope allow for both airglow and solar occultation observations during the mission. The focal plane detector is an imaging microchannel plate (MCP) double delay-line detector with dual solar-blind opaque photocathodes (KBr and CsI) and a focal surface that matches the instrument’s 15-cm diameter Rowland-circle. In this paper, we describe the instrument in greater detail, including descriptions of its ground calibration and initial in flight performance. New Horizons launched on 19 January 2006.

  19. A passive cost-effective solution for the high accuracy wavelength calibration of radial velocity spectrographs

    NASA Astrophysics Data System (ADS)

    Wildi, Françcis; Chazelas, Bruno; Pepe, Francesco

    2012-09-01

    Today, the RV technique has pushed the planet detection limits down to super-earths but the reach the precision required to detect earth-like planets it is necessary to reach a precision around 1cm s-1. While a significant part of the error budget is the incompressible photon noise, another part is the noise in the wavelength calibration of the spectrograph. In the past 3 years the Observatory of Geneva has designed, built and tested an commissioned 2 wavelength calibrator systems based on a Fabry-Perot (FP) interferometer with great success. The calibrator system demonstrated 10 cm s-1 stability over one night and 1 m s-1 over 60 days. By improving the system injecting the calibration light into the calibration fiber of the spectrograph we are aiming at 1 m s-1 repeatability over the long term. This technique is now being extended to cover the near infrared to the K band in the frame of the SPIROU project.

  20. The UV multi-object slit-spectrograph FIREBall-2 simulator

    NASA Astrophysics Data System (ADS)

    Mège, P.; Pascal, S.; Quiret, S.; Corlies, L.; Vibert, D.; Grange, R.; Milliard, B.

    2015-08-01

    The FIREBall-2 Instrument Model (FIREBallIMO) is a piece of software simulating the optical behaviour of the Multi-Object Two-Curved Schmidt Slit Spectograph of FIREBall-2 (Faint Intergalactic Redshifted Emission BALLoon), a balloon-borne telescope (40 km in alt.) designed to perform a direct detection of the faint Circum Galactic Medium (CGM) in emission around low-z galaxies. The spectrograph has been optimized to operate in a narrow UV band [195-225] nanometers, the so-called atmospheric sweet spot, where the sky background presents no emission lines and can be considered approximately flat, a value of 500 continnum units, seen through an optical transmission of 50% at an atmospheric pressure of 3 millibars. This paper gives an overview of the software current modular architecture after a year of productive effort (in terms of parametric model space definition, associated data cubes generation and digital processing) starting from the instrument initial optical model designed under Zemax software to the final 2D-detected image. A special emphasis is put on the design of a cython-wrapped driver able to retrieve dense ray-sampled PSFs out of the Zemax box efficiently. The optical mappings and distortions from the sky to the spectrograph's entrance slit plane and from the sky to the detection plane are presented, as well as some end-to-end simulations leading to Signal-to-Noise Ratio estimates computed on artificial point-like or extended test sources.

  1. Spectrographic temperature measurement of a high power breakdown arc in a high pressure gas switch

    SciTech Connect

    Yeckel, Christopher; Curry, Randy

    2011-09-15

    A procedure for obtaining an approximate temperature value of conducting plasma generated during self-break closure of a RIMFIRE gas switch is described. The plasma is in the form of a breakdown arc which conducts approximately 12 kJ of energy in 1 {mu}s. A spectrographic analysis of the trigger-section of the 6-MV RIMFIRE laser triggered gas switch used in Sandia National Laboratory's ''Z-Machine'' has been made. It is assumed that the breakdown plasma has sufficiently approached local thermodynamic equilibrium allowing a black-body temperature model to be applied. This model allows the plasma temperature and radiated power to be approximated. The gas dielectric used in these tests was pressurized SF{sub 6}. The electrode gap is set at 4.59 cm for each test. The electrode material is stainless steel and insulator material is poly(methyl methacrylate). A spectrum range from 220 to 550 nanometers has been observed and calibrated using two spectral irradiance lamps and three spectrograph gratings. The approximate plasma temperature is reported.

  2. Spectrographic measures of the speech of young children with cleft lip and cleft palate.

    PubMed

    Casal, C; Domínguez, C; Fernández, A; Sarget, R; Martínez-Celdrán, E; Sentís-Vilalta, J; Gay-Escoda, C

    2002-01-01

    Twenty-two consecutive children with repaired cleft lip and/or palate [isolated cleft lip (CL) 6, isolated cleft palate (CP) 7, unilateral cleft lip and palate (UCLP) 7, and bilateral cleft lip and palate 2] with a mean age of 27 months underwent spectrographic measures of tape-recorded speech (DSP Sona-Graph digital unit). Controls were 22 age- and sex-matched noncleft children. Data analyzed included (1) the Spanish vocalic variables [a, i, u, e, o]: first formant, second formant, duration, and context; (2) obstruent variables [p, t, k]: burst, voice onset time, and duration, and (3) nasal variables [m]: first formant, second formant, and duration. Statistically significant differences were observed between the CL group and the control group in the first formant of [e] and in the increase of the frequency of the [t] burst. Comparison between UCLP and controls showed differences in the second formant of [a], in the first formant of [o], and in the second formant of [o]. These results suggest a small but significant influence of either the cleft lip or its repair on lip rounding for [o] and [u]. In addition, tongue position differences were most likely responsible for the differences seen with [a] and [e]. Spectrographic differences in the current patients did not contribute to meaningful differences in speech sound development. Individualized care (orthodontics, surgery, speech therapy) in children with cleft lip and/or palate attended at specialized craniofacial units contributes to normalization of speech development. PMID:12378036

  3. Invariant distributions on compact homogeneous spaces

    SciTech Connect

    Gorbatsevich, V V

    2013-12-31

    In this paper, we study distributions on compact homogeneous spaces, including invariant distributions and also distributions admitting a sub-Riemannian structure. We first consider distributions of dimension 1 and 2 on compact homogeneous spaces. After this, we study the cases of compact homogeneous spaces of dimension 2, 3, and 4 in detail. Invariant distributions on simply connected compact homogeneous spaces are also treated. Bibliography: 18 titles.

  4. 7 CFR 51.582 - Fairly compact.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Standards for Celery Definitions § 51.582 Fairly compact. Fairly compact means that the branches on the... 7 Agriculture 2 2010-01-01 2010-01-01 false Fairly compact. 51.582 Section 51.582 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  5. 7 CFR 51.572 - Compact.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Standards for Celery Definitions § 51.572 Compact. Compact means that the branches on the stalk are fairly... 7 Agriculture 2 2010-01-01 2010-01-01 false Compact. 51.572 Section 51.572 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  6. 7 CFR 51.572 - Compact.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standards for Celery Definitions § 51.572 Compact. Compact means that the branches on the stalk are fairly... 7 Agriculture 2 2011-01-01 2011-01-01 false Compact. 51.572 Section 51.572 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  7. 7 CFR 51.582 - Fairly compact.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standards for Celery Definitions § 51.582 Fairly compact. Fairly compact means that the branches on the... 7 Agriculture 2 2011-01-01 2011-01-01 false Fairly compact. 51.582 Section 51.582 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  8. Rapid compaction during RNA folding

    NASA Astrophysics Data System (ADS)

    Russell, Rick; Millett, Ian S.; Tate, Mark W.; Kwok, Lisa W.; Nakatani, Bradley; Gruner, Sol M.; Mochrie, Simon G. J.; Pande, Vijay; Doniach, Sebastian; Herschlag, Daniel; Pollack, Lois

    2002-04-01

    We have used small angle x-ray scattering and computer simulations with a coarse-grained model to provide a time-resolved picture of the global folding process of the Tetrahymena group I RNA over a time window of more than five orders of magnitude. A substantial phase of compaction is observed on the low millisecond timescale, and the overall compaction and global shape changes are largely complete within one second, earlier than any known tertiary contacts are formed. This finding indicates that the RNA forms a nonspecifically collapsed intermediate and then searches for its tertiary contacts within a highly restricted subset of conformational space. The collapsed intermediate early in folding of this RNA is grossly akin to molten globule intermediates in protein folding.

  9. Compact torus studies: Final report

    SciTech Connect

    Morse, E.C.

    1987-06-01

    The compact torus (CT) device has been proposed for use in some applications which are of interest in Laboratory programs in the areas of pulsed power and inertial confinement fusion. These applications involve compression and acceleration of CT plasmas. The RACE (Ring Accelerator Experiment) experimental program at Livermore has been initiated to study these applications. The work reported here involves studies of plasma physics and other aspects of these compact torus applications. The studies conducted identify specific problem areas associated with the CT device and examine these areas in some detail. This report contains studies of three particular problem areas of the CT applications. These three areas are: the general nonlinear properties of the CT as a magnetohydrodynamic (MHD) equilibrium, particle simulation of the compression of the CT, with a focus on the non-MHD effects, and nonlinear RF interaction problems in the CT.

  10. FMOS the fibre multiple-object spectrograph, part VIII: current performances and results of the engineering observations

    NASA Astrophysics Data System (ADS)

    Kimura, Masahiko; Akiyama, Masayuki; Dalton, Gavin B.; Iwamuro, Fumihide; Lewis, Ian J.; Maihara, Toshinori; Ohta, Kouji; Tait, Philip; Takato, Naruhisa; Tamura, Naoyuki; Tosh, Ian A. J.; Smedley, Scott; Curtis Lake, Emma; Inagaki, Takeshi; Jeschke, Eric; Kawate, Kaori; Moritani, Yuuki; Sumiyoshi, Masanao; Yabe, Kiyoto

    2010-07-01

    The Fibre Multi-Object Spectrograph for Subaru Telescope (FMOS) is a near-infrared instrument with 400 fibres in a 30' filed of view at F/2 prime focus. To observe 400 objects simultaneously, we have developed a fibre positioner called "Echidna" using a tube piezo actuator. We have also developed two OH-airglow suppressed and refrigerated spectrographs. Each spectrograph has two spectral resolution modes: the low-resolution mode and the high-resolution mode. The low-resolution mode covers the complete wavelength range of 0.9 - 1.8 μm with one exposure, while the high-resolution mode requires four exposures at different camera positions to cover the full wavelength range. The first light was accomplished in May 2008. The science observations and the open-use observations begin in May 2010.

  11. LEMUR (Large European Module for solar Ultraviolet Research): a VUV imaging spectrograph for the JAXA Solar-C Mission

    NASA Astrophysics Data System (ADS)

    Korendyke, Clarence M.; Teriaca, Luca; Doschek, George A.; Harra, Louise K.; Schühle, Udo H.; Shimizu, Toshifumi

    2011-10-01

    LEMUR is a VUV imaging spectrograph with 0.28" resolution. Incident solar radiation is imaged onto the spectrograph slit by a single mirror telescope consisting of a 30-cm steerable f/12 off-axis paraboloid mirror. The spectrograph slit is imaged and dispersed by a highly corrected grating that focuses the solar spectrum over the detectors. The mirror is coated with a suitable multilayer with B4C top-coating providing a reflectance peak around 18.5 nm besides the usual B4C range above 500Å. The grating is formed by two halves, one optimized for performances around 185Å and the other above 500Å. Three intensified CCD cameras will record spectra above 50 nm while a large format CCD array with an aluminum filter will be used around 185Å.

  12. Compact portable diffraction moire interferometer

    DOEpatents

    Deason, V.A.; Ward, M.B.

    1988-05-23

    A compact and portable moire interferometer used to determine surface deformations of an object. The improved interferometer is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent wave splitters, and collimating lenses directing the split beam at one or more specimen gratings. Observations means including film and video cameras may be used to view and record the resultant fringe patterns. 7 figs.

  13. Compact portable diffraction moire interferometer

    DOEpatents

    Deason, Vance A.; Ward, Michael B.

    1989-01-01

    A compact and portable moire interferometer used to determine surface deformations of an object. The improved interferometer is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent wave splitters, and collimating lenses directing the split beam at one or more specimen gratings. Observation means including film and video cameras may be used to view and record the resultant fringe patterns.

  14. Compact planar microwave blocking filters

    NASA Technical Reports Server (NTRS)

    U-Yen, Kongpop (Inventor); Wollack, Edward J. (Inventor)

    2012-01-01

    A compact planar microwave blocking filter includes a dielectric substrate and a plurality of filter unit elements disposed on the substrate. The filter unit elements are interconnected in a symmetrical series cascade with filter unit elements being organized in the series based on physical size. In the filter, a first filter unit element of the plurality of filter unit elements includes a low impedance open-ended line configured to reduce the shunt capacitance of the filter.

  15. Compact magnetic energy storage module

    DOEpatents

    Prueitt, M.L.

    1994-12-20

    A superconducting compact magnetic energy storage module in which a plurality of superconducting toroids, each having a toroidally wound superconducting winding inside a poloidally wound superconducting winding, are stacked so that the flow of electricity in each toroidally wound superconducting winding is in a direction opposite from the direction of electrical flow in other contiguous superconducting toroids. This allows for minimal magnetic pollution outside of the module. 4 figures.

  16. Compact magnetic energy storage module

    DOEpatents

    Prueitt, Melvin L.

    1994-01-01

    A superconducting compact magnetic energy storage module in which a plurality of superconducting toroids, each having a toroidally wound superconducting winding inside a poloidally wound superconducting winding, are stacked so that the flow of electricity in each toroidally wound superconducting winding is in a direction opposite from the direction of electrical flow in other contiguous superconducting toroids. This allows for minimal magnetic pollution outside of the module.

  17. COMB: Compact embedded object simulations

    NASA Astrophysics Data System (ADS)

    McEwen, Jason D.

    2016-06-01

    COMB supports the simulation on the sphere of compact objects embedded in a stochastic background process of specified power spectrum. Support is provided to add additional white noise and convolve with beam functions. Functionality to support functions defined on the sphere is provided by the S2 code (ascl:1606.008); HEALPix (ascl:1107.018) and CFITSIO (ascl:1010.001) are also required.

  18. 78 FR 61384 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-03

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... of this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  19. 76 FR 20044 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-11

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  20. 75 FR 62568 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-12

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact). Thus far,...

  1. 75 FR 17161 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-05

    ... Federal Bureau of Investigation Meeting of the Compact Council for the National Crime Prevention and... purpose of this notice is to announce a meeting of the National Crime Prevention and Privacy Compact Council (Council) created by the National Crime Prevention and Privacy Compact Act of 1998 (Compact)....

  2. Compaction Waves in Granular HMX

    SciTech Connect

    E. Kober; R. Menikoff

    1999-01-01

    Piston driven compaction waves in granular HMX are simulated with a two-dimensional continuum mechanics code in which individual grains are resolved. The constitutive properties of the grains are modeled with a hydrostatic pressure and a simple elastic-plastic model for the shear stress. Parameters are chosen to correspond to inert HMX. For a tightly packed random grain distribution (with initial porosity of 19%) we varied the piston velocity to obtain weak partly compacted waves and stronger fully compacted waves. The average stress and wave speed are compatible with the porous Hugoniot locus for uni- axial strain. However, the heterogeneities give rise to stress concentrations, which lead to localized plastic flow. For weak waves, plastic deformation is the dominant dissipative mechanism and leads to dispersed waves that spread out in time. In addition to dispersion, the granular heterogeneities give rise to subgrain spatial variation in the thermodynamic variables. The peaks in the temperature fluctuations, known as hot spots, are in the range such that they are the critical factor for initiation sensitivity.

  3. Compact Stellarator Path to DEMO

    NASA Astrophysics Data System (ADS)

    Lyon, J. F.

    2007-11-01

    Issues for a DEMO reactor are sustaining an ignited/high-Q plasma in steady state, avoiding disruptions and large variations in power flux to the wall, adequate confinement of thermal plasma and alpha-particles, control of a burning plasma, particle and power handling, etc. Compact stellarators have key advantages -- steady-state high-plasma-density operation without external current drive or disruptions, stability without a close conducting wall or active feedback systems, and low recirculating power -- in addition to moderate plasma aspect ratio, good confinement, and high-beta potential. The ARIES-CS study established that compact stellarators can be competitive with tokamaks as reactors. Many of the issues for a compact stellarator DEMO can be answered using results from large tokamaks, ITER D-T experiments and fusion materials, technology and component development programs, in addition to stellarators in operation, under construction or in development. However, a large next-generation stellarator will be needed to address some physics issues: size scaling and confinement at higher parameters, burning plasma issues, and operation with a strongly radiative divertor. Technology issues include simpler coils, structure, and divertor fabrication, and better cost information.

  4. THE MULTI-OBJECT, FIBER-FED SPECTROGRAPHS FOR THE SLOAN DIGITAL SKY SURVEY AND THE BARYON OSCILLATION SPECTROSCOPIC SURVEY

    SciTech Connect

    Smee, Stephen A.; Barkhouser, Robert H.; Gunn, James E.; Carr, Michael A.; Lupton, Robert H.; Loomis, Craig; Uomoto, Alan; Roe, Natalie; Schlegel, David; Rockosi, Constance M.; Leger, French; Owen, Russell; Anderson, Lauren; Dawson, Kyle S.; Olmstead, Matthew D.; Brinkmann, Jon; Long, Dan; Honscheid, Klaus; Harding, Paul; Annis, James; and others

    2013-08-01

    We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5 m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Ly{alpha} absorption of 160,000 high redshift quasars over 10,000 deg{sup 2} of sky, making percent level measurements of the absolute cosmic distance scale of the universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber spectrographs utilize a simple optical layout with reflective collimators, gratings, all-refractive cameras, and state-of-the-art CCD detectors to produce hundreds of spectra simultaneously in two channels over a bandpass covering the near-ultraviolet to the near-infrared, with a resolving power R = {lambda}/FWHM {approx} 2000. Building on proven heritage, the spectrographs were upgraded for BOSS with volume-phase holographic gratings and modern CCD detectors, improving the peak throughput by nearly a factor of two, extending the bandpass to cover 360 nm < {lambda} < 1000 nm, and increasing the number of fibers from 640 to 1000 per exposure. In this paper we describe the original SDSS spectrograph design and the upgrades implemented for BOSS, and document the predicted and measured performances.

  5. Performance testing of a novel off-plane reflection grating and silicon pore optic spectrograph at PANTER

    NASA Astrophysics Data System (ADS)

    Marlowe, Hannah; McEntaffer, Randall L.; Allured, Ryan; DeRoo, Casey; Miles, Drew M.; Donovan, Benjamin D.; Tutt, James H.; Burwitz, Vadim; Menz, Benedikt; Hartner, Gisela D.; Smith, Randall K.; Günther, Ramses; Yanson, Alex; Vacanti, Giuseppe; Ackermann, Marcelo

    2015-05-01

    An X-ray spectrograph consisting of aligned, radially ruled off-plane reflection gratings and silicon pore optics (SPO) was tested at the Max Planck Institute for extraterrestrial Physics PANTER X-ray test facility. The SPO is a test module for the proposed Arcus mission, which will also feature aligned off-plane reflection gratings. This test is the first time two off-plane gratings were actively aligned to each other and with a SPO to produce an overlapped spectrum. We report the performance of the complete spectrograph utilizing the aligned gratings module and plans for future development.

  6. Ray-tracing the convex curved crystal X-ray spectrograph. [instrument design and data interpretation technique

    NASA Technical Reports Server (NTRS)

    Kastner, S. O.

    1979-01-01

    The convex curved crystal X-ray spectrograph has recently seen increasing use for the spectral analysis of transient plasmas. The present paper describes the calculation of ray paths through the spectrograph for both localized and extended sources. The method traces a ray from any given source point to its point of diffraction by the curved crystal and then to the imaging circle, where the image point is obtained. Application of the ray tracing method is made to some actual experimental configurations to obtain resolution values and source sizes. Wavelength calibrations are obtainable with the ray tracing method in advance of instrument construction.

  7. IMAPS - A high-resolution, echelle spectrograph to record far-ultraviolet spectra of stars from sounding rockets

    NASA Technical Reports Server (NTRS)

    Jenkins, E. B.; Joseph, C. L.; Long, D.; Zucchino, P. M.; Carruthers, G. R.

    1988-01-01

    A novel sounding rocket payload consisting of a slitless objective grating spectrograph with no transmission elements in the optical train (or detector) is described. This instrument, called the interstellar medium absorption profile spectrograph (IMAPS), is designed to provide continuous coverage over the wavelength range of 950-1150 A; it has an effective collecting area of about 4 sq cm and can record spectra of pointlike sources at a wavelength resolution of 0.004 A and with a sample interval of 0.002 A. The successful use of this instrument aboard a Black Brant rocket is described.

  8. The infrared imaging spectrograph (IRIS) for TMT: reflective ruled diffraction grating performance testing and discussion

    NASA Astrophysics Data System (ADS)

    Meyer, Elliot; Chen, Shaojie; Wright, Shelley A.; Moore, Anna M.; Larkin, James E.; Simard, Luc; Marie, Jerome; Mieda, Etsuko; Gordon, Jacob

    2014-07-01

    We present the efficiency of near-infrared reflective ruled diffraction gratings designed for the InfraRed Imaging Spectrograph (IRIS). IRIS is a first light, integral field spectrograph and imager for the Thirty Meter Telescope (TMT) and narrow field infrared adaptive optics system (NFIRAOS). IRIS will operate across the near-infrared encompassing the ZYJHK bands (~0.84 - 2.4μm) with multiple spectral resolutions. We present our experimental setup and analysis of the efficiency of selected reflective diffraction gratings. These measurements are used as a comparison sample against selected candidate Volume Phase Holographic (VPH) gratings (see Chen et al., this conference). We investigate the efficiencies of five ruled gratings designed for IRIS from two separate vendors. Three of the gratings accept a bandpass of 1.19-1.37μm (J band) with ideal spectral resolutions of R=4000 and R=8000, groove densities of 249 and 516 lines/mm, and blaze angles of 9.86° and 20.54° respectively. The other two gratings accept a bandpass of 1.51-1.82μm (H Band) with an ideal spectral resolution of R=4000, groove density of 141 lines/mm, and blaze angle of 9.86°. The fraction of flux in each diffraction mode was compared to both a pure reflection mirror as well as the sum of the flux measured in all observable modes. We measure the efficiencies off blaze angle for all gratings and the efficiencies between the polarization transverse magnetic (TM) and transverse electric (TE) states. The peak reflective efficiencies are 98.90 +/- 3.36% (TM) and 84.99 +/- 2.74% (TM) for the H-band R=4000 and J-band R=4000 respectively. The peak reflective efficiency for the J-band R=8000 grating is 78.78 +/- 2.54% (TE). We find that these ruled gratings do not exhibit a wide dependency on incident angle within +/-3°. Our best-manufactured gratings were found to exhibit a dependency on the polarization state of the incident beam with a ~10-20% deviation, consistent with the theoretical efficiency

  9. The infrared imaging spectrograph (IRIS) for TMT: volume phase holographic grating performance testing and discussion

    NASA Astrophysics Data System (ADS)

    Chen, Shaojie; Meyer, Elliot; Wright, Shelley A.; Moore, Anna M.; Larkin, James E.; Maire, Jerome; Mieda, Etsuko; Simard, Luc

    2014-07-01

    Maximizing the grating efficiency is a key goal for the first light instrument IRIS (Infrared Imaging Spectrograph) currently being designed to sample the diffraction limit of the TMT (Thirty Meter Telescope). Volume Phase Holographic (VPH) gratings have been shown to offer extremely high efficiencies that approach 100% for high line frequencies (i.e., 600 to 6000l/mm), which has been applicable for astronomical optical spectrographs. However, VPH gratings have been less exploited in the near-infrared, particularly for gratings that have lower line frequencies. Given their potential to offer high throughputs and low scattered light, VPH gratings are being explored for IRIS as a potential dispersing element in the spectrograph. Our team has procured near-infrared gratings from two separate vendors. We have two gratings with the specifications needed for IRIS current design: 1.51-1.82μm (H-band) to produce a spectral resolution of 4000 and 1.19-1.37μm (J-band) to produce a spectral resolution of 8000. The center wavelengths for each grating are 1.629μm and 1.27μm, and the groove densities are 177l/mm and 440l/mm for H-band R=4000 and J-band R=8000, respectively. We directly measure the efficiencies in the lab and find that the peak efficiencies of these two types of gratings are quite good with a peak efficiency of ~88% at the Bragg angle in both TM and TE modes at H-band, and 90.23% in TM mode, 79.91% in TE mode at J-band for the best vendor. We determine the drop in efficiency off the Bragg angle, with a 20-23% decrease in efficiency at H-band when 2.5° deviation from the Bragg angle, and 25%-28% decrease at J-band when 5° deviation from the Bragg angle.

  10. A High Resolution Solar Spectrograph for the Berkeley Undergraduate Astronomy Lab

    NASA Astrophysics Data System (ADS)

    Strickler, R.; Bresloff, C.; Graham, J.

    2005-05-01

    The discovery of extra-solar planets has stimulated interest amongst undergraduates. The Doppler method for detecting exoplanets requires extraction of signals at the 1/1000 of a pixel level. To illustrate this technique, we used a newly built spectrometer to extract sub-pixel Doppler shifts in the solar photosphere. We have used this spectrograph to measure the velocity gradient across the sun and hence infer the solar radius. The limb-to-limb Doppler shift is only 1.8 km/s. A spectral resolution > 100,000 would be required to manifest this motion. Achieving such high spectral resolution is unnecessary since even a small telescope can record high SNR (> 100) spectra. Within a few seconds it is possible to discern solar rotational Doppler shifts at resolutions as low as 10,000. We must also understand coordinate transformation to convert the Doppler signal along the observed diameter to the equatorial rotation speed assuming solid body rotation. The spectrograph system includes an 8-inch Schmidt-Cassegrain stationary telescope; a 100-micron diameter multi-mode fiber; aspheric f-number reformatting optics; a collimating lens; a 110 mm, 80 grooves/mm, θ blaze = 64.5 degree replica echelle grating; and an Apogee 1024 x 1024 thermo-electrically cooled CCD. The spectrometer optics are mounted on a 5-ft x 3-ft optical bench. Operating the spectrometer remotely using VNC and a wireless laptop, we pointed the telescope so that the fiber scanned across a diameter of the solar disk while the CCD took repeated exposures. Although we were "guinea pigs," using the spectrograph for the first time in a class, it worked remarkably well. Combining measurement of the solar radius with observation of the rotation period from sunspots, the earth-sun distance can be deduced. In the future, students may measure the eccentricity of earth's orbit by measuring the sun's radial velocity over the course of a year. This work was supported by the NSF through award DUE-0311536.

  11. Unified compaction curve model for tensile strength of tablets made by roller compaction and direct compression.

    PubMed

    Farber, Leon; Hapgood, Karen P; Michaels, James N; Fu, Xi-Young; Meyer, Robert; Johnson, Mary-Ann; Li, Feng

    2008-01-01

    A model that describes the relationship between roller-compaction conditions and tablet strength is proposed. The model assumes that compaction is cumulative during roller compaction and subsequent granule compaction, and compact strength (ribbon and tablet) is generated irreversibly as if strength is controlled by plastic deformation of primary particles only. Roller-compaction is treated as a compaction step where the macroscopic ribbon strength is subsequently destroyed in milling. This loss in strength is irreversible and tablets compressed from the resulting granulation are weaker than those compressed by direct compression at the same compression force. Roller-compacted ribbons were produced at a range of roll forces for three formulations and subsequently milled and compacted into tablets. Once the total compaction history is taken in account, the compaction behavior of the uncompacted blends and the roller-compacted granules ultimately follow a single master compaction curve--a unified compaction curve (UCC). The model successfully described the compaction behavior of DC grade starch and formulations of lactose monohydrate with 50% or more microcrystalline cellulose, and may be more generally applicable to systems containing significant proportions of any plastically deforming material, including MCC and starch. PMID:17689211

  12. Observing Resolved Stellar Populations with the JWST Near-Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Gilbert, K. M.; Beck, T. L.; Karakla, D. M.

    2016-10-01

    The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) will provide a multi-object spectroscopy (MOS) mode through the Micro-Shutter Array (MSA). Each MSA quadrant is a grid of contiguous shutters that can be configured to form slits on more than 100 astronomical targets simultaneously. The combination of JWST's sensitivity and superb resolution in the infrared and NIRSpec's full wavelength coverage over 0.6 to 5 μm will open new parameter space for studies of galaxies and resolved stellar populations alike. We describe a NIRSpec MSA observing scenario of spectroscopy of individual stars in an external galaxy, and investigate the technical challenges posed by this scenario. This use case and others, including a deep galaxy survey and observations of Galactic HII regions, are guiding development of the NIRSpec user interfaces including proposal planning and pipeline calibrations.

  13. MIRADAS - The Next-Generation Near-Infrared Spectrograph for the GTC

    NASA Astrophysics Data System (ADS)

    Eikenberry, S. S.

    2013-05-01

    We describe the Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS) being developed by the MIRADAS Consortium institutions (including the University of Florida, Universidad de Barcelona, Universidad Complutense de Madrid, Instituto Astrofísica de Canarias, Institut de Física d' Altes Energies, Institut d' Estudis Espacials de Catalunya and Universidad Nacional Autonoma de México) for the Gran Telescopio Canarias. MIRADAS is the most powerful astronomical instrument of its kind ever envisioned. The combination of the collecting area of GTC and the multi-object mid-resolution near-infrared spectra provided by MIRADAS make its capabilities unparalleled for addressing some of the leading scientific challenges of the coming decades, with an observing efficiency more than an order of magnitude greater than current capabilities for 10-meter-class telescopes. We briefly review the science drivers for the instrument, the basic design features, and the current status of the instrument development.

  14. A mask quality control tool for the OSIRIS multi-object spectrograph

    NASA Astrophysics Data System (ADS)

    López-Ruiz, J. C.; Vaz Cedillo, Jacinto Javier; Ederoclite, Alessandro; Bongiovanni, Ángel; González Escalera, Víctor

    2012-09-01

    OSIRIS multi object spectrograph uses a set of user-customised-masks, which are manufactured on-demand. The manufacturing process consists of drilling the specified slits on the mask with the required accuracy. Ensuring that slits are on the right place when observing is of vital importance. We present a tool for checking the quality of the process of manufacturing the masks which is based on analyzing the instrument images obtained with the manufactured masks on place. The tool extracts the slit information from these images, relates specifications with the extracted slit information, and finally communicates to the operator if the manufactured mask fulfills the expectations of the mask designer. The proposed tool has been built using scripting languages and using standard libraries such as opencv, pyraf and scipy. The software architecture, advantages and limits of this tool in the lifecycle of a multiobject acquisition are presented.

  15. First results from the Goddard High-Resolution Spectrograph - The chromosphere of Alpha Tauri

    NASA Technical Reports Server (NTRS)

    Carpenter, Kenneth G.; Robinson, Richard D.; Wahlgren, Glenn M.; Ake, Thomas B.; Ebbets, Dennis C.

    1991-01-01

    The K5 III star Alpha Tau was observed with the Goddard High Resolution Spectrograph on November 27, 1990 as part of the Science Assessment Program for the HST. The spectra show intersystem and permitted chromospheric emission lines of semiforbidden C II and Si II, Fe II, Fe I, Ni II, and Co II. Resolved profiles of the semiforbidden C II lines indicate a complex chromospheric turbulent velocity distribution with mean value of roughly 24 km/s, while their observed wavelengths indicate a 4 km/s downflow of the semiforbidden C II plasma. Twenty-five new emission lines have been found in the 2320-2370 A region, 17 of which have been identified with the aid of Skylab data obtained above the solar limb, including four lines from Co II (UV 8) and an Fe I (UV 12) line.

  16. Creating Data that Never Die: Building a Spectrograph Data Pipeline in the Virtual Observatory Era

    NASA Astrophysics Data System (ADS)

    Mink, D. J.; Wyatt, W. F.; Roll, J. B.; Tokarz, S. P.; Conroy, M. A.; Caldwell, N.; Kurtz, M.; Geller, M. J.

    2005-12-01

    Data pipelines for modern complex astronomical instruments do not begin when the data is taken and end when it is delivered to the user. Information must flow between the observatory and the observer from the time a project is conceived and between the observatory and the world well past the time when the original observers have extracted all the information they want from the data. For the 300-fiber Hectospec low dispersion spectrograph on the MMT, the SAO Telescope Data Center is constructing a data pipeline which provides assistance from preparing and submitting observing proposals through observation, reduction, and analysis to publication and an afterlife in the Virtual Observatory. We will describe our semi-automatic pipeline and how it has evolved over the first nine months of operation.

  17. Research directed toward improved echelles for the ultraviolet. [large space teslescope spectrographs

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Low frequency gratings obtainable with present technology, can meet the grating-efficiency design goals for potential space telescope spectrographs. Gratings made with changes in the three specific parameters: the ruling tool profile, the coating material, and the lubricants used during the ruling process were compared. A series of coatings and test gratings were fabricated and were examined for surface smoothness with a Nomarski differential interference microscope and an electron microsocope. Photomicrographs were obtained to show the difference in smoothness of the various coatings and rulings. Efficiency measurements were made for those test rulings that showed good groove characteristics: smoothness, proper ruling depth, and absence of defects (e.g., streaks, feathered edges and rough sides). Higher grating efficiency should be correlated with the degree of smoothness of both the coating and the grating groove.

  18. On-instrument wavefront sensor design for the TMT infrared imaging spectrograph (IRIS) update

    NASA Astrophysics Data System (ADS)

    Dunn, Jennifer; Reshetov, Vladimir; Atwood, Jenny; Pazder, John; Wooff, Bob; Loop, David; Saddlemyer, Leslie; Moore, Anna M.; Larkin, James E.

    2014-08-01

    The first light instrument on the Thirty Meter Telescope (TMT) project will be the InfraRed Imaging Spectrograph (IRIS). IRIS will be mounted on a bottom port of the facility AO instrument NFIRAOS. IRIS will report guiding information to the NFIRAOS through the On-Instrument Wavefront Sensor (OIWFS) that is part of IRIS. This will be in a self-contained compartment of IRIS and will provide three deployable wavefront sensor probe arms. This entire unit will be rotated to provide field de-rotation. Currently in our preliminary design stage our efforts have included: prototyping of the probe arm to determine the accuracy of this critical component, handling cart design and reviewing different types of glass for the atmospheric dispersion.

  19. Novel Spectrograph/Radiometer for Cloud Top Height Measurement Using Three Complementary Techniques

    NASA Technical Reports Server (NTRS)

    Park, Hongwoo; Soulen, Peter F.; Prasad, Coorg R.

    1997-01-01

    A proof-of-concept (POC) instrument system to measure cloud top height from space using three complementary techniques is presented. These techniques use measurements of: (1) thermal infrared (IR); (2) molecular oxygen 'A' band absorption; and (3) filling-in of Fraunhofer lines (the Ring effect), respectively. Combining three techniques is achieved with a single grating spectrograph with bandpass and order sorting filters by measuring I I jim radiation from the zeroth order of the grating for the IR, 750-780 nm radiation from the first order for the 'A' band absorption, and 390-400 mn radiation from the second order for the Ca K and H Fraunhofer line filling-in effect. The POC system and its measurement results with the POC system are described.

  20. Observations of Resolved Stellar Populations with the JWST Near Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Gilbert, Karoline; Beck, Tracy L.; Karakla, Diane M.

    2015-01-01

    The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) will provide a multi-object spectroscopy mode through the four Micro-Shutter Arrays (MSAs). Each MSA is a grid of contiguous shutters that can be configured to form slits on more than 100 astronomical targets simultaneously. The combination of JWST's sensitivity and superb resolution in the infrared and NIRSpec's full wavelength coverage over 1 to 5 micrometers will open new parameter space for studies of galaxies and resolved stellar populations alike. We present a NIRSpec MSA observing scenario for obtaining spectroscopy of individual stars in external galaxies. We examine the multiplexing capability of the MSA as a function of the possible MSA configuration design choices, and investigate the primary sources of error in velocity measurements and the prospects for minimizing them. We discuss how this and other use cases are being used to guide development of the NIRSpec user interfaces, including proposal planning and pipeline calibrations.

  1. Emission spectrographic determination of volatile trace elements in geologic materials by a carrier distillation technique

    USGS Publications Warehouse

    Barton, H.N.

    1986-01-01

    Trace levels of chalcophile elements that form volatile sulfide minerals are determined in stream sediments and in the nonmagnetic fraction of a heavy-mineral concentrate of stream sediments by a carrier distillation emission spectrographic method. Photographically recorded spectra of samples are visually compared with those of synthetic standards for the two sample types. Rock and soil samples may also be analyzed by comparison with the stream-sediment standards. A gallium oxide spectrochemical carrier/buffer enhances the early emission of the volatile elements. Detection limits in parts per million attained are: Sb 5, As 20, Bi 0.1, Cd 1, Cu 1, Pb 2, Ag 0.1, Zn 2, and Sn 0.1. A comparison with other methods of analysis, total-burn emission and atomic absorption spectroscopy, shows good correlation for standard reference for materials and samples from a variety of geologic terranes. ?? 1986.

  2. Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) for WFIRST/AFTA

    NASA Technical Reports Server (NTRS)

    Gong, Qian; McElwain, Michael; Greeley, Bradford; Grammer, Bryan; Marx, Catherine; Memarsadeghi, Nargess; Hilton, George; Perrin, Marshall; Sayson, Llop; Domingo, Jorge; Stapelfeldt, Karl

    2015-01-01

    Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) is a prototype lenslet array based integral field spectrometer (IFS) designed for high contrast imaging of extrasolar planets. PISCES will be used to advance the technology readiness of the high contrast IFS baselined on the Wide-Field InfraRed Survey TelescopeAstrophysics Focused Telescope Assets (WFIRSTAFTA) coronagraph instrument. PISCES will be integrated into the high contrast imaging testbed (HCIT) at the Jet Propulsion Laboratory and will work with both the Hybrid Lyot Coronagraph (HLC) and the Shaped Pupil Coronagraph (SPC). We will present the PISCES optical design, including the similarities and differences of lenslet based IFSs to normal spectrometers, the trade-off between a refractive design and reflective design, as well as the compatibility to upgrade from the current 1k x 1k detector array to 4k x 4k detector array. The optical analysis, alignment plan, and mechanical design of the instrument will be discussed.

  3. Characterization and on-sky demonstration of an integrated photonic spectrograph for astronomy.

    PubMed

    Cvetojevic, N; Lawrence, J S; Ellis, S C; Bland-Hawthorn, J; Haynes, R; Horton, A

    2009-10-12

    We present results from the first on-sky demonstration of a prototype astronomical integrated photonic spectrograph (IPS) using the Anglo-Australian Telescope near-infrared imaging spectrometer (IRIS2) at Siding Spring Observatory to observe atmospheric molecular OH emission lines. We have succeeded in detecting upwards of 27 lines, and demonstrated the practicality of the IPS device for astronomy. Furthermore, we present a laboratory characterization of the device, which is a modified version of a commercial arrayed-waveguide grating multiplexer. We measure the spectral resolution full-width-half-maximum to be 0.75 +/- 0.05 nm (giving R = lambda/deltalambda = 2100 +/- 150 at 1500 nm). We find the free spectral range to be 57.4 +/- 0.6 nm and the peak total efficiency to be approximately 65%. Finally, we briefly discuss the future steps required to realize an astronomical instrument based on this technology concept.

  4. Updated Status and Performance for the Cosmic Origins Spectrograph Onboard the Hubble Space Telescope

    NASA Astrophysics Data System (ADS)

    Taylor, Joanna M.; Aloisi, A.; Bacinski, J.; Bostroem, K. A.; Debes, J. H.; Roman-Duval, J.; Ely, J.; DiFelice, A.; Hernandez, S.; Kriss, G. A.; Hodge, P.; Lindsay, K.; Lockwood, S. A.; Massa, D.; Oliveira, C. M.; Osten, R. A.; Penton, S. V.; Proffitt, C. R.; Sahnow, D. J.; Sonnentrucker, P.; Wheeler, T.

    2013-06-01

    The Cosmic Origins Spectrograph (COS) was installed on the Hubble Space Telescope in May 2009. Although COS was initially designed to perform high-sensitivity medium- and low-resolution spectroscopy of astronomical objects in the 1150-3200 Å wavelength range, new wavelength settings have recently become available that allow medium-resolution spectroscopy down to 900 Å, at effective areas comparable to those of FUSE. Here we provide an update on the implementation of the new short wavelength settings G130M/1222, 1096, and 1055. We discuss changes to the Far-Ultraviolet (FUV) and Near-Ultraviolet (NUV) dark rates, FUV pulse height filtering, new and improved flux calibrations for FUV Lifetime Positions 1 and 2, changes in sensitivity for both the NUV and FUV channels, and give a general overview of the calibration projects undertaken in Cycles 19 and 20.

  5. The GIRAFFE Archive: Reduced Spectra and Datacubes from the VLT FLAMES GIRAFFE Spectrograph

    NASA Astrophysics Data System (ADS)

    Royer, F.; Jégouzo, I.; Haigron, R.; Tajahmady, F.; Plassard, F.

    2014-12-01

    Since 2003, the intermediate- and high-resolution multi-fibre spectrograph GIRAFFE, part of the FLAMES facility, has been producing 1D spectra in its multi-object configuration and 3D spectra using its integral field unit configurations. Raw data are available in the ESO archive. The GIRAFFE archive (http://giraffe-archive.obspm.fr) offers the community, via a web interface and the Virtual Observatory (VO), access to reduced scientific data. The web interface to the database allows the use of a large range of selection criteria, including individual target positions, magnitudes and signal-to-noise ratios, together with an interactive quick look at the reduced data. Two collections are available in the VO: the 1D spectra (summed in the case of integral field observations) and the 3D field observations.

  6. CARMENES: A New Visible/Near-IR Radial-Velocity Spectrograph

    NASA Astrophysics Data System (ADS)

    Quirrenbach, Andreas; Carmenes Consortium

    2016-07-01

    CARMENES is a next-generation radial-velocity instrument that has been constructed for the 3.5m telescope at the Calar Alto Observatory by a consortium of eleven Spanish and German institutions. It consists of two separate échelle spectrographs covering the wavelength range from 0.55 to 1.7μm at a spectral resolution of R = 82,000, fed by fibers from the Cassegrain focus of the telescope. CARMENES saw "First Light" on Nov 9, 2015. We report on results from the commissioning and the first months of operation, and discuss the plans for the large M dwarf survey that is the core science program of CARMENES. With a bit of luck, CARMENES may find a few planets that are very well suited for characterization by JWST. In the longer run, CARMENES will be an excellent instrument for radial-velocity follow-up of transit survey missions such as TESS and PLATO.

  7. Extreme Ultraviolet Variability Experiment (EVE) Multiple EUV Grating Spectrographs (MEGS): Radiometric Calibrations and Results

    NASA Technical Reports Server (NTRS)

    Hock, R. A.; Woods, T. N.; Crotser, D.; Eparvier, F. G.; Woodraska, D. L.; Chamberlin, P. C.; Woods, E. C.

    2010-01-01

    The NASA Solar Dynamics Observatory (SDO), scheduled for launch in early 2010, incorporates a suite of instruments including the Extreme Ultraviolet Variability Experiment (EVE). EVE has multiple instruments including the Multiple Extreme ultraviolet Grating Spectrographs (MEGS) A, B, and P instruments, the Solar Aspect Monitor (SAM), and the Extreme ultraviolet SpectroPhotometer (ESP). The radiometric calibration of EVE, necessary to convert the instrument counts to physical units, was performed at the National Institute of Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF III) located in Gaithersburg, Maryland. This paper presents the results and derived accuracy of this radiometric calibration for the MEGS A, B, P, and SAM instruments, while the calibration of the ESP instrument is addressed by Didkovsky et al. . In addition, solar measurements that were taken on 14 April 2008, during the NASA 36.240 sounding-rocket flight, are shown for the prototype EVE instruments.

  8. Spectrographic analysis of the ultrasonic vocalisations of adult male and female BALB/c mice

    NASA Astrophysics Data System (ADS)

    Gourbal, Benjamin E. F.; Barthelemy, Mathieu; Petit, Gilles; Gabrion, Claude

    In this study, a spectrographic analysis was designed to improve the description of the shape, the modulations, the rate, length and frequencies of BALB/c mouse calls in different behavioural situations. Male and female calls emitted during investigation of cages with clean bedding, soiled with male or female bedding, and during same-sex encounters, were recorded and described. BALB/c male mice uttered different types of vocalisations both when investigating counterpart odour cues and when interacting with same-sex counterparts. BALB/c female mice vocalised solely during same-sex counterpart encounters and it appeared that calls were uttered mainly by the resident females. Male and female mice present a complex array of calls, which seem to be linked to particular behavioural situations. Further studies using this technology may help to improve our understanding of the role of vocal communication in natural rodent populations.

  9. A technique using a stellar spectrographic plate to measure terrestrial ozone column depth

    SciTech Connect

    Wong, A.Y.

    1995-08-01

    This thesis examines the feasibility of a technique to extract ozone column depths from photographic stellar spectra in the 5000--7000 Angstrom spectral region. A stellar spectrographic plate is measured to yield the relative intensity distribution of a star`s radiation after transmission through the earth`s atmosphere. The amount of stellar radiation absorbed by the ozone Chappuis band is proportional to the ozone column depth. The measured column depth is within 10% the mean monthly value for latitude 36{degree}N, however the uncertainty is too large to make the measurement useful. This thesis shows that a 10% improvement to the photographic sensitivity uncertainty can decrease the column depth uncertainty to a level acceptable for climatic study use. This technique offers the possibility of measuring past ozone column depths.

  10. Industrial solutions trends for the control of HiRes spectrograph@E-ELT

    NASA Astrophysics Data System (ADS)

    Di Marcantonio, P.; Baldini, V.; Calderone, G.; Cirami, R.; Coretti, I.; Cristiani, S.

    Starting a few years ago, ESO initiated a number of projects aiming to explore the possible adoption of industrial standards and commercial off-the-shelf components (COTS) for the control of future VLT and E-ELT instrumentations. In this context, ESPRESSO, the next generation high-stability spectrograph for the VLT and to a certain extent, a precursor of HiRes, has adopted since the preliminary design phase those solutions. Based on the ESPRESSO experience and taking into account the requirements inferred from the preliminary Hi-Res studies in terms of both high-level operations as well as low-level control, I will present in this paper the current proposal for the HiRes hardware architecture.

  11. The control unit of the near infrared spectrograph of the Euclid space mission: detailed design

    NASA Astrophysics Data System (ADS)

    Toledo-Moreo, Rafael; Colodro-Conde, Carlos; Gómez-Sáenz-de-Tejada, Jaime; Pérez-Lizán, David; Díaz-García, José Javier; Tubío-Araujo, Óscar; Raichs, Cayetano; Catalán, Jordi; Rebolo-López, Rafael

    2016-07-01

    The Near Infrared Spectrograph and Photometer (NISP) is one of the instruments on board the ESA EUCLID mission. The Universidad Politécnica de Cartagena and Instituto de Astrofísica de Canarias are responsible of the Instrument Control Unit of the NISP (NI-ICU) in the Euclid Consortium. The NI-ICU hardware is developed by CRISA (Airbus Defence and Space), and its main functions are: communication with the S/C and the Data Processing Unit, control of the Filter and Grism Wheels, control of the Calibration Unit and thermal control of the instrument. This paper presents the NI-ICU status of definition and design at the end of the detailed design phase.

  12. The EMIR Near-Infrared Multi-Object Spectrograph for GTC

    NASA Astrophysics Data System (ADS)

    Balcells, M.

    1998-06-01

    EMIR is a near-infrared (NIR) multi-object spectrograph (MOS) proposed for first-generation common user instrument of the Gran Telescopio Canarias GTC. It has three observing modes: imaging, multiobject spectroscopy and integral-field spectroscopy, in the NIR Z, J, H and K bands. The design uses cryogenic multislit masks to allow simultaneous spectroscopy of up to approximately 50 objects. The spectral resolution R=5000 allows for effective "see through" the OH line forest that dominates the J and H sky backgrounds. EMIR addresses one of the fundamental goals of large telescopes, the spectroscopy of large quantities of faint sources. Science applications include young stellar objects embedded in molecular clouds, brown dwarfs, stellar clusters, resolved population in external galaxies and distant galaxies. EMIR is being designed by a consortium of Spanish, UK and French Institutes. Project updates and information will be posted at http://www.ucm.es/info/emir/.

  13. Radiometric performance results of the New Horizons' ALICE UV imaging spectrograph

    NASA Astrophysics Data System (ADS)

    Slater, David C.; Davis, Michael W.; Olkin, Catherine B.; Scherrer, John; Stern, S. Alan

    2005-09-01

    We describe the radiometric performance and calibration results of the New Horizons' ALICE flight model. This ALICE is a lightweight (4.4 kg), low-power (4.4 W), ultraviolet spectrograph based on the ALICE instrument now in flight aboard the European Space Agency's Rosetta spacecraft. Its primary job will be to detect a variety of important atomic and molecular species in Pluto's atmosphere, and to determine their relative abundances so that a complete picture of Pluto's atmospheric composition can be determined for the first time. ALICE will also be used to search for an atmosphere around Pluto's moon, Charon, as well as the Kuiper Belt Objects (KBOs) New Horizons hopes to fly by after Pluto-Charon. Detailed radiometric performance results of the ALICE flight model are presented and discussed.

  14. A Laser Frequency Comb System for Absolute Calibration of the VTT Echelle Spectrograph

    NASA Astrophysics Data System (ADS)

    Doerr, H.-P.; Steinmetz, T.; Holzwarth, R.; Kentischer, T.; Schmidt, W.

    2012-10-01

    A wavelength calibration system based on a laser frequency comb (LFC) was developed in a co-operation between the Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany and the Max-Planck-Institut für Quantenoptik, Garching, Germany for permanent installation at the German Vacuum Tower Telescope (VTT) on Tenerife, Canary Islands. The system was installed successfully in October 2011. By simultaneously recording the spectra from the Sun and the LFC, for each exposure a calibration curve can be derived from the known frequencies of the comb modes that is suitable for absolute calibration at the meters per second level. We briefly summarize some topics in solar physics that benefit from absolute spectroscopy and point out the advantages of LFC compared to traditional calibration techniques. We also sketch the basic setup of the VTT calibration system and its integration with the existing echelle spectrograph.

  15. Update on the Status of the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope

    NASA Astrophysics Data System (ADS)

    Hernandez, Svea; Aloisi, A.; Bostroem, K. A.; Cox, C.; Debes, J. H.; DiFelice, A.; Roman-Duval, J.; Hodge, P.; Holland, S.; Lindsay, K.; Lockwood, S. A.; Mason, E.; Oliveira, C. M.; Penton, S. V.; Proffitt, C. R.; Sonnentrucker, P.; Taylor, J. M.; Wheeler, T.

    2013-06-01

    The Space Telescope Imaging Spectrograph (STIS) has been on orbit for approximately 16 years as one of the 2nd generation instruments on the Hubble Space Telescope (HST). Its operations were interrupted by an electronics failure in 2004, but STIS was successfully repaired in May 2009 during Service Mission 4 (SM4) allowing it to resume science observations. The Instrument team continues to monitor its performance and work towards improving the quality of its products. Here we present updated information on the status of the FUV and NUV MAMA and the CCD detectors onboard STIS and describe recent changes to the STIS calibration pipeline. We also discuss the status of efforts to apply a pixel-based correction for charge transfer inefficiency (CTI) effects to STIS CCD data. These techniques show promise for ameliorating the effects of ongoing radiation damage on the quality of STIS CCD data.

  16. Compaction of Space Mission Wastes

    NASA Technical Reports Server (NTRS)

    Fisher, John; Pisharody, Suresh; Wignarajah, K.

    2004-01-01

    The current solid waste management system employed on the International Space Station (ISS) consists of compaction, storage, and disposal. Wastes such plastic food packaging and trash are compacted manually and wrapped in duct tape footballs by the astronauts. Much of the waste is simply loaded either into the empty Russian Progress vehicle for destruction on reentry or into Shuttle for return to Earth. This manual method is wasteful of crew time and does not transition well to far term missions. Different wastes onboard spacecraft vary considerably in their characteristics and in the appropriate method of management. In advanced life support systems for far term missions, recovery of resources such as water from the wastes becomes important. However waste such as plastic food packaging, which constitutes a large fraction of solid waste (roughly 21% on ISS, more on long duration missions), contains minimal recoverable resource. The appropriate management of plastic waste is waste stabilization and volume minimization rather than resource recovery. This paper describes work that has begun at Ames Research Center on development of a heat melt compactor that can be used on near term and future missions, that can minimize crew interaction, and that can handle wastes with a significant plastic composition. The heat melt compactor takes advantage of the low melting point of plastics to compact plastic materials using a combination of heat and pressure. The US Navy has demonstrated successful development of a similar unit for shipboard application. Ames is building upon the basic approach demonstrated by the Navy to develop an advanced heat melt type compactor for space mission type wastes.

  17. An Infrared Multi-Object Spectrograph (IRMS) with adaptive optics for TMT: the science case

    NASA Astrophysics Data System (ADS)

    Mobasher, Bahram; Crampton, David; Simard, Luc

    2010-07-01

    It has been recognized that a Near-Infrared Multi-object Spectrograph (IRMS) as one of the first light instrument on the Thirty Meter Telescope (TMT) would significantly increase the scientific capability of the observatory. The IRMS is planned to be a clone of the MOSFIRE instrument on the Keck telescope. As a result, we use the already available MOSFIRE design and expertise, significantly reducing the total cost and its development time. The IRMS will be a quasi diffraction limited multi-slit spectrograph with moderate resolution (R~4000), fed by Narrow-Field Infrared Adaptive Optics System (NFIRAOS). It images over the 2 arcmin diameter field of view of the NFIRAOS. There are a number of exceedingly important scientific questions, waiting to be addressed by the TMT/IRMS combination. Given its relatively small field of view, it is less affected by the sky background, which is a limiting factor in ground-based observations at near-IR wavelengths. The IRMS is the ideal instrument for studying spectroscopic properties of galaxies at the re-ionization epoch (z > 7), where the Lyman alpha line shifts to the near-ir wavelenghths. It can be used to measure rotation curves of spiral and velocity dispersion of elliptical galaxies at z~2-3 and hence, their spectroscopic mass. It can be used to search for population III stars via their spectroscopic signature and to perform measurement of spectroscopic lines at high redshifts, diagnostic of metallicity. Finally, IRMS allows measurement of the blue shifts in the rest-frame MgII line for high redshift galaxies, used to study the winds, leading to the feedback mechanism, responsible for quenching star formation activity in galaxies.

  18. The assembly, calibration, and preliminary results from the Colorado high-resolution Echelle stellar spectrograph (CHESS)

    NASA Astrophysics Data System (ADS)

    Hoadley, Keri; France, Kevin; Nell, Nicholas; Kane, Robert; Schultz, Ted; Beasley, Matthew; Green, James; Kulow, Jen; Kersgaard, Eliot; Fleming, Brian

    2014-07-01

    The Colorado High-resolution Echelle Stellar Spectrograph (CHESS) is a far ultraviolet (FUV) rocket-borne experiment designed to study the atomic-to-molecular transitions within translucent interstellar clouds. CHESS is an objective echelle spectrograph operating at f/12.4 and resolving power of 120,000 over a band pass of 100 - 160 nm. The echelle flight grating is the product of a research and development project with LightSmyth Inc. and was coated at Goddard Space Flight Center (GSFC) with Al+LiF. It has an empirically-determined groove density of 71.67 grooves/mm. At the Center for Astrophysics and Space Astronomy (CASA) at the University of Colorado (CU), we measured the efficiencies of the peak and adjacent dispersion orders throughout the 90 - 165 nm band pass to characterize the behavior of the grating for pre-flight calibrations and to assess the scattered-light behavior. The crossdispersing grating, developed and ruled by Horiba Jobin-Yvon, is a holographically-ruled, low line density (351 grooves/mm), powered optic with a toroidal surface curvature. The CHESS cross-disperser was also coated at GSFC; Cr+Al+LiF was deposited to enhance far-UV efficiency. Results from final efficiency and reflectivity measurements of both optics are presented. We utilize a cross-strip anode microchannel plate (MCP) detector built by Sensor Sciences to achieve high resolution (25 μm spatial resolution) and data collection rates (~ 106 photons/second) over a large format (40mm round, digitized to 8k x 8k) for the first time in an astronomical sounding rocket flight. The CHESS instrument was successfully launched from White Sands Missile Range on 24 May 2014. We present pre-flight sensitivity, effective area calculations, lab spectra and calibration results, and touch on first results and post-flight calibration plans.

  19. MAVEN Imaging UV Spectrograph Results on the Mars Atmosphere and Atmospheric Escape

    NASA Astrophysics Data System (ADS)

    Chaffin, Michael; Schneider, Nick; McClintock, Bill; Stewart, Ian; Deighan, Justin; Jain, Sonal; Clarke, John; Holsclaw, Greg; Montmessin, Franck; Lefevre, Franck; Chaufray, Jean-Yves; Stiepen, Arnaud; Crismani, Matteo; Mayyasi, Majd; Evans, Scott; Stevens, Mike; Yelle, Roger; Jakosky, Bruce

    2016-04-01

    The Imaging Ultraviolet Spectrograph (IUVS) is one of nine science instruments aboard the Mars Atmosphere and Volatile and EvolutioN (MAVEN) spacecraft, whose payload is dedicated to exploring the upper atmosphere of Mars and understanding the magnitude and drivers of Mars' atmospheric escape rate. IUVS uses ultraviolet light to investigate the lower and upper atmosphere and ionosphere of Mars. The instrument is among the most powerful spectrographs sent to another planet, with several key capabilities: (1) separate Far-UV & Mid-UV channels for stray light control, (2) a high resolution echelle mode to resolve deuterium and hydrogen emission, (3) internal instrument pointing and scanning capabilities to allow complete mapping and nearly continuous operation, and (4) optimization for airglow studies. IUVS, along with other MAVEN instruments, obtains a comprehensive picture of the current state of the Mars upper atmosphere and ionosphere and the processes that control atmospheric escape. We present an overview of selected IUVS results, including (1) the discovery of diffuse aurora at Mars, and its contrast with previously detected discrete aurora localized near crustal magnetic fields; (2) widespread detection of mesospheric clouds; (3) Significant seasonal and short-timescale variability in thermospheric composition; (4) Global ozone maps spanning six months of seasonal evolution; and (5) mapping of the Mars H and O coronas, deriving the escape rates of H and O and their variability. This last is of particular importance for understanding the long term evolution of Mars and its atmosphere, with the observed preset escape of H potentially capable of removing a large fraction of Mars' initial water inventory, and the differential escape of O relative to H potentially providing a net source of oxidizing power to the atmosphere and planet at present, in contrast with a photochemical theory that predicts stoichiometrically balanced escape. The atmospheric and escape

  20. Development of the Colorado High-resolution Echelle Stellar Spectrograph (CHESS)

    NASA Astrophysics Data System (ADS)

    France, Kevin; Beasley, Matthew; Kane, Robert; Nell, Nicholas; Burgh, Eric B.; Green, James C.

    2012-09-01

    A key astrophysical theme that will drive future UV/optical space missions is the life cycle of cosmic matter, from the flow of intergalactic gas into galaxies to the formation and evolution of exoplanetary systems. Spectroscopic systems capable of delivering high resolution with low backgrounds will be essential to addressing these topics. Towards this end, we are developing a rocket-borne instrument that will serve as a pathfinder for future high-sensitivity, highresolution UV spectrographs. The Colorado High-resolution Echelle Stellar Spectrograph (CHESS) will provide 2 km s-1 velocity resolution (R = 150,000) over the 100 - 160 nm bandpass that includes key atomic and molecular spectral diagnostics for the intergalactic medium (H I Lyman-series, O VI, N V, and C IV), exoplanetary atmospheres (H I Lyman-alpha, O I, and C II), and protoplanetary disks (H2 and CO electronic band systems). CHESS uses a novel mechanical collimator comprised of an array of 10 mm x 10 mm stainless steel tubes to feed a low-scatter, 69 grooves mm-1 echelle grating. The cross-disperser is a holographically ruled toroid, with 351 grooves mm-1. The spectral orders can be recorded with either a 40 mm cross-strip microchannel plate detector or a 3.5k x 3.5k δ-doped CCD. The microchannel plate will deliver 30 μm spatial resolution and employs new 64 amp/axis electronics to accommodate high count rate observations of local OB stars. CHESS is scheduled to be launched aboard a NASA Terrier/Black Brant IX sounding rocket from White Sands Missile Range in the summer of 2013.