The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Gary J. Hill - One of the best experts on this subject based on the ideXlab platform.
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virus the instrument infrastructure to support the deployment and upkeep of 156 Spectrographs at the hobby eberly telescope
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III, 2018Co-Authors: Renny Spencer, Gary J. Hill, John M Good, Edmundo Balderrama, George Damm, James R Fowler, Hermanus Kriel, Emily Mrozinski, Dave M Perry, Matthew D ShetroneAbstract:The Visible Integral-field Replicable Unit Spectrograph (VIRUS) consists of 156 identical Spectrographs fed by 35,000 fibers from the upgraded 10-meter Hobby-Eberly Telescope (HET). VIRUS is in a phased deployment. At the submission of this paper, over half of the units are installed and the full support infrastructure is operational. This paper will describe the VIRUS infrastructure which includes the physical support system, the air cooling, the cryogenic cooling, and the temperature control of VIRUS. The paper will also discuss the various installation, maintenance, and operational procedures based on growing experience with the VIRUS array.
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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
Proceedings of SPIE, 2014Co-Authors: Gary J. Hill, Sarah Tuttle, Eva Noyola, Trent Peterson, Brian L VattiatAbstract: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.
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replicated Spectrographs in astronomy
Advanced Optical Technologies, 2014Co-Authors: Gary J. HillAbstract: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.
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initial results from virus production Spectrographs
Proceedings of SPIE, 2012Co-Authors: Sarah Tuttle, Gary J. Hill, J L Marshall, D L Depoy, Richard D Allen, Marc D Rafal, Taylor S Chonis, Mark E Cornell, Travis Prochaska, Richard SavageAbstract: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 bers 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 rst batch of 16 is in progress. A brief overview of the assembly is presented, and where available performance is compared to specication.
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production line assembly of 150 virus Spectrographs
Proceedings of SPIE, 2010Co-Authors: J L Marshall, Andreas Kelz, Gary J. Hill, Brian L Vattiat, D L Depoy, Amanda D Collins, Richard D Allen, Svend M Bauer, Emil PopowAbstract: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.
Stephen A. Smee - One of the best experts on this subject based on the ideXlab platform.
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the apache point observatory galactic evolution experiment apogee Spectrographs
Publications of the Astronomical Society of the Pacific, 2019Co-Authors: John C Wilson, James E. Gunn, Frederick R Hearty, M F Skrutskie, S R Majewski, J Holtzman, Daniel J Eisenstein, Basil Blank, C P Henderson, Stephen A. SmeeAbstract:We describe the design and performance of the near-infrared (1.51--1.70 micron), fiber-fed, multi-object (300 fibers), high resolution (R = lambda/delta lambda ~ 22,500) spectrograph built for the Apache Point Observatory Galactic Evolution Experiment (APOGEE). APOGEE is a survey of ~ 10^5 red giant stars that systematically sampled all Milky Way populations (bulge, disk, and halo) to study the Galaxy's chemical and kinematical history. It was part of the Sloan Digital Sky Survey III (SDSS-III) from 2011 -- 2014 using the 2.5 m Sloan Foundation Telescope at Apache Point Observatory, New Mexico. The APOGEE-2 survey is now using the spectrograph as part of SDSS-IV, as well as a second spectrograph, a close copy of the first, operating at the 2.5 m du Pont Telescope at Las Campanas Observatory in Chile. Although several fiber-fed, multi-object, high resolution Spectrographs have been built for visual wavelength spectroscopy, the APOGEE spectrograph is one of the first such instruments built for observations in the near-infrared. The instrument's successful development was enabled by several key innovations, including a "gang connector" to allow simultaneous connections of 300 fibers; hermetically sealed feedthroughs to allow fibers to pass through the cryostat wall continuously; the first cryogenically deployed mosaic volume phase holographic grating; and a large refractive camera that includes mono-crystalline silicon and fused silica elements with diameters as large as ~ 400 mm. This paper contains a comprehensive description of all aspects of the instrument including the fiber system, optics and opto-mechanics, detector arrays, mechanics and cryogenics, instrument control, calibration system, optical performance and stability, lessons learned, and design changes for the second instrument.
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SUBARU prime focus spectrograph: integration, testing and performance for the first spectrograph
Proceedings of SPIE, 2016Co-Authors: F. Madec, David Le Mignant, James E. Gunn, Stephen A. Smee, K. Dohlen, R. Barrette, M. Belhadi, S. Pascal, J. Le MerrerAbstract:The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project for Subaru telescope consists in four identical Spectrographs fed 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 visibles and one near infrared. This paper presents the on-going effort for the tests and integration process for the first spectrograph channel: we have developed a detailed Assembly Integration and Test (AIT) plan, as well as the methods, detailed processes and I and T tools. We describe the tools we designed to assemble the parts and to test the performance of the spectrograph. We also report on the thermal acceptance tests we performed on the first visible camera unit. We also report on and discuss the technical difficulties that did appear during this integration phase. Finally, we detail the important logistic process that is require to transport the components from other country to Marseille.
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the multi object fiber fed Spectrographs for the sloan digital sky survey and the baryon oscillation spectroscopic survey
The Astronomical Journal, 2013Co-Authors: Stephen A. Smee, David J. Schlegel, James E. Gunn, Michael A. Carr, Alan Uomoto, Constance M Rockosi, F Leger, Kyle S Dawson, Matthew D Olmstead, Jon BrinkmannAbstract: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 Lyα absorption of 160,000 high redshift quasars over 10,000 deg2 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 = λ/FWHM ~ 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 < λ < 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.
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A spectrograph instrument concept for the Prime Focus Spectrograph (PFS) on Subaru Telescope
Proceedings of SPIE, 2012Co-Authors: Sébastien Vivès, E. Prieto, David Le Mignant, F. Madec, M. Jaquet, Laurent Martin, Olivier Le Fèvre, James E. Gunn, Michael A. Carr, Stephen A. SmeeAbstract:We describe the conceptual design of the spectrograph opto-mechanical concept for the SuMIRe Prime Focus Spectrograph (PFS) being developed for the SUBARU telescope. The SuMIRe PFS will consist of four identical Spectrographs, each receiving 600 fibers from a 2400 fiber robotic positioner at the prime focus. Each spectrograph will have three channels covering in total, a wavelength range from 380 nm to 1300 nm. The requirements for the instrument are summarized in Section 1. We present the optical design and the optical performance and analysis in Section 2. Section 3 introduces the mechanical design, its requirements and the proposed concepts. Finally, the AIT phases for the Spectrograph System are described in Section 5.
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the multi object fiber fed Spectrographs for sdss and the baryon oscillation spectroscopic survey
arXiv: Instrumentation and Methods for Astrophysics, 2012Co-Authors: Stephen A. Smee, David J. Schlegel, James E. Gunn, Michael A. Carr, Alan Uomoto, Constance M Rockosi, F Leger, Kyle S Dawson, Matthew D Olmstead, Jon BrinkmannAbstract: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 Lyman-alpha absorption of 160,000 high redshift quasars over 10,000 square degrees 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 ~ 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 < \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.
Yuri Shvydko - One of the best experts on this subject based on the ideXlab platform.
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theory of angular dispersive imaging hard x ray Spectrographs
Physical Review A, 2015Co-Authors: Yuri ShvydkoAbstract:A spectrograph is an optical instrument that disperses photons of different energies into distinct directions and space locations, and images photon spectra on a position-sensitive detector. Spectrographs consist of collimating, angular dispersive, and focusing optical elements. Bragg reflecting crystals arranged in an asymmetric scattering geometry are used as the dispersing elements. A ray-transfer matrix technique is applied to propagate x-rays through the optical elements. Several optical designs of hard x-ray Spectrographs are proposed and their performance is analyzed. Spectrographs with an energy resolution of 0.1 meV and a spectral window of imaging up to a few tens of meVs are shown to be feasible for inelastic x-ray scattering (IXS) spectroscopy applications. In another example, a spectrograph with a 1-meV spectral resolution and 85-meV spectral window of imaging is considered for Cu K-edge resonant IXS (RIXS).
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hard x ray Spectrographs with resolution beyond 100 micro ev
Physical Review A, 2013Co-Authors: Yuri Shvydko, Stanislav Stoupin, K MundbothAbstract:Spectrographs take snapshots of photon spectra with array detectors by dispersing photons of different energies into distinct directions and spacial locations. Spectrographs require optics with a large angular dispersion rate as the key component. In visible light optics diffraction gratings are used for this purpose. In the hard x-ray regime, achieving large dispersion rates is a challenge. Here we show that multi-crystal, multi-Bragg-reflection arrangements feature cumulative angular dispersion rates almost two orders of magnitude larger than those attainable with a single Bragg reflection. As a result, the multi-crystal arrangements become potential dispersing elements of hard x-ray Spectrographs. The hard x-ray spectrograph principles are demonstrated by imaging a spectrum of photons with a record high resolution of $\Delta E \simeq 90 \mu$eV in hard x-ray regime, using multi-crystal optics as dispersing element. The Spectrographs can boost research using inelastic ultra-high-resolution x-ray spectroscopies with synchrotrons and seeded XFELs.
James E. Gunn - One of the best experts on this subject based on the ideXlab platform.
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the apache point observatory galactic evolution experiment apogee Spectrographs
Publications of the Astronomical Society of the Pacific, 2019Co-Authors: John C Wilson, James E. Gunn, Frederick R Hearty, M F Skrutskie, S R Majewski, J Holtzman, Daniel J Eisenstein, Basil Blank, C P Henderson, Stephen A. SmeeAbstract:We describe the design and performance of the near-infrared (1.51--1.70 micron), fiber-fed, multi-object (300 fibers), high resolution (R = lambda/delta lambda ~ 22,500) spectrograph built for the Apache Point Observatory Galactic Evolution Experiment (APOGEE). APOGEE is a survey of ~ 10^5 red giant stars that systematically sampled all Milky Way populations (bulge, disk, and halo) to study the Galaxy's chemical and kinematical history. It was part of the Sloan Digital Sky Survey III (SDSS-III) from 2011 -- 2014 using the 2.5 m Sloan Foundation Telescope at Apache Point Observatory, New Mexico. The APOGEE-2 survey is now using the spectrograph as part of SDSS-IV, as well as a second spectrograph, a close copy of the first, operating at the 2.5 m du Pont Telescope at Las Campanas Observatory in Chile. Although several fiber-fed, multi-object, high resolution Spectrographs have been built for visual wavelength spectroscopy, the APOGEE spectrograph is one of the first such instruments built for observations in the near-infrared. The instrument's successful development was enabled by several key innovations, including a "gang connector" to allow simultaneous connections of 300 fibers; hermetically sealed feedthroughs to allow fibers to pass through the cryostat wall continuously; the first cryogenically deployed mosaic volume phase holographic grating; and a large refractive camera that includes mono-crystalline silicon and fused silica elements with diameters as large as ~ 400 mm. This paper contains a comprehensive description of all aspects of the instrument including the fiber system, optics and opto-mechanics, detector arrays, mechanics and cryogenics, instrument control, calibration system, optical performance and stability, lessons learned, and design changes for the second instrument.
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SUBARU prime focus spectrograph: integration, testing and performance for the first spectrograph
Proceedings of SPIE, 2016Co-Authors: F. Madec, David Le Mignant, James E. Gunn, Stephen A. Smee, K. Dohlen, R. Barrette, M. Belhadi, S. Pascal, J. Le MerrerAbstract:The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project for Subaru telescope consists in four identical Spectrographs fed 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 visibles and one near infrared. This paper presents the on-going effort for the tests and integration process for the first spectrograph channel: we have developed a detailed Assembly Integration and Test (AIT) plan, as well as the methods, detailed processes and I and T tools. We describe the tools we designed to assemble the parts and to test the performance of the spectrograph. We also report on the thermal acceptance tests we performed on the first visible camera unit. We also report on and discuss the technical difficulties that did appear during this integration phase. Finally, we detail the important logistic process that is require to transport the components from other country to Marseille.
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the multi object fiber fed Spectrographs for the sloan digital sky survey and the baryon oscillation spectroscopic survey
The Astronomical Journal, 2013Co-Authors: Stephen A. Smee, David J. Schlegel, James E. Gunn, Michael A. Carr, Alan Uomoto, Constance M Rockosi, F Leger, Kyle S Dawson, Matthew D Olmstead, Jon BrinkmannAbstract: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 Lyα absorption of 160,000 high redshift quasars over 10,000 deg2 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 = λ/FWHM ~ 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 < λ < 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.
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A spectrograph instrument concept for the Prime Focus Spectrograph (PFS) on Subaru Telescope
Proceedings of SPIE, 2012Co-Authors: Sébastien Vivès, E. Prieto, David Le Mignant, F. Madec, M. Jaquet, Laurent Martin, Olivier Le Fèvre, James E. Gunn, Michael A. Carr, Stephen A. SmeeAbstract:We describe the conceptual design of the spectrograph opto-mechanical concept for the SuMIRe Prime Focus Spectrograph (PFS) being developed for the SUBARU telescope. The SuMIRe PFS will consist of four identical Spectrographs, each receiving 600 fibers from a 2400 fiber robotic positioner at the prime focus. Each spectrograph will have three channels covering in total, a wavelength range from 380 nm to 1300 nm. The requirements for the instrument are summarized in Section 1. We present the optical design and the optical performance and analysis in Section 2. Section 3 introduces the mechanical design, its requirements and the proposed concepts. Finally, the AIT phases for the Spectrograph System are described in Section 5.
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the multi object fiber fed Spectrographs for sdss and the baryon oscillation spectroscopic survey
arXiv: Instrumentation and Methods for Astrophysics, 2012Co-Authors: Stephen A. Smee, David J. Schlegel, James E. Gunn, Michael A. Carr, Alan Uomoto, Constance M Rockosi, F Leger, Kyle S Dawson, Matthew D Olmstead, Jon BrinkmannAbstract: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 Lyman-alpha absorption of 160,000 high redshift quasars over 10,000 square degrees 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 ~ 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 < \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.
Jon Brinkmann - One of the best experts on this subject based on the ideXlab platform.
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the multi object fiber fed Spectrographs for the sloan digital sky survey and the baryon oscillation spectroscopic survey
The Astronomical Journal, 2013Co-Authors: Stephen A. Smee, David J. Schlegel, James E. Gunn, Michael A. Carr, Alan Uomoto, Constance M Rockosi, F Leger, Kyle S Dawson, Matthew D Olmstead, Jon BrinkmannAbstract: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 Lyα absorption of 160,000 high redshift quasars over 10,000 deg2 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 = λ/FWHM ~ 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 < λ < 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.
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the multi object fiber fed Spectrographs for sdss and the baryon oscillation spectroscopic survey
arXiv: Instrumentation and Methods for Astrophysics, 2012Co-Authors: Stephen A. Smee, David J. Schlegel, James E. Gunn, Michael A. Carr, Alan Uomoto, Constance M Rockosi, F Leger, Kyle S Dawson, Matthew D Olmstead, Jon BrinkmannAbstract: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 Lyman-alpha absorption of 160,000 high redshift quasars over 10,000 square degrees 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 ~ 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 < \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.
