John Wilson, F. Hearty, M. Skrutskie, S. Majewski, R. Schiavon, D. Eisenstein, J. Gunn, J. Holtzman, D. Nidever, B. Gillespie, D. Weinberg, B. Blank, C. Henderson, S. Smee, R. Barkhouser, A. Harding, S. Hope, G. Fitzgerald, T. Stolberg, J. Arns, M. Nelson, S. Brunner, A. Burton, E. Walker, C. Lam, P. Maseman, J. Barr, F. Leger, L. Carey, N. MacDonald, G. Ebelke, S. Beland, T. Horne, E. Young, G. Rieke, M. Rieke, T. O'Brien, J. Crane, M. Carr, C. Harrison, R. Stoll, M. Vernieri, M. Shetrone, C. Allende-Prieto, J. Johnson, P. Frinchaboy, G. Zasowski, A. Garcia Perez, D. Bizyaev, K. Cunha, V. Smith, Sz. Meszaros, B. Zhao, M. Hayden, S. D. Chojnowski, B. Andrews, C. Loomis, R. Owen, M. Klaene, J. Brinkmann, F. Stauffer, D. Long, W. Jordan, D. Holder, F. Cope, T. Naugle, B. Pfaffenberger, D. Schlegel, M. Blanton, D. Muna, B. Weaver, S. Snedden, K. Pan, H. Brewington, E. Malanushenko, V. Malanushenko, A. Simmons, D. Oravetz, S. Mahadevan, S. Halverson
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) uses a dedicated 300-fiber, narrow-band
near-infrared (1.51-1.7 μm), high resolution (R~22,500) spectrograph to survey approximately 100,000 giant stars across
the Milky Way. This three-year survey, in operation since late-summer 2011 as part of the Sloan Digital Sky Survey III
(SDSS III), will revolutionize our understanding of the kinematical and chemical enrichment histories of all Galactic
stellar populations. We present the performance of the instrument from its first year in operation. The instrument is
housed in a separate building adjacent to the 2.5-m SDSS telescope and fed light via approximately 45-meter fiber runs
from the telescope. The instrument design includes numerous innovations including a gang connector that allows
simultaneous connection of all fibers with a single plug to a telescope cartridge that positions the fibers on the sky,
numerous places in the fiber train in which focal ratio degradation had to be minimized, a large mosaic-VPH (290 mm x
475 mm elliptically-shaped recorded area), an f/1.4 six-element refractive camera featuring silicon and fused silica
elements with diameters as large as 393 mm, three near-infrared detectors mounted in a 1 x 3 mosaic with sub-pixel
translation capability, and all of these components housed within a custom, LN2-cooled, stainless steel vacuum cryostat
with dimensions 1.4-m x 2.3-m x 1.3-m.
Volume phase holographic (VPH) gratings are increasingly being used as diffractive elements in astronomical
instruments due to their potential for very high peak diffraction efficiencies and the possibility of a compact instrument
design when the gratings are used in transmission. Historically, VPH grating (VPHG) sizes have been limited by the size
of manufacturer's holographic recording optics. We report on the design, specification and fabrication of a large, 290
mm × 475 mm elliptically-shaped, mosaic VPHG for the Apache Point Observatory Galactic Evolution Experiment
(APOGEE) spectrograph. This high-resolution near-infrared multi-object spectrograph is in construction for the Sloan
Digital Sky Survey III (SDSS III). The 1008.6 lines/mm VPHG was designed for optimized performance over a
wavelength range from 1.5 to 1.7 μm. A step-and-repeat exposure method was chosen to fabricate a three-segment
mosaic on a 305 mm × 508 mm monolithic fused-silica substrate. Specification considerations imposed on the VPHG to
assure the mosaic construction will satisfy the end use requirements are discussed. Production issues and test results of
the mosaic VPHG are discussed.
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) will use a dedicated 300-fiber, narrow-band
(1.5-1.7 micron), high resolution (R~30,000), near-infrared spectrograph to survey approximately 100,000 giant stars
across the Milky Way. This survey, conducted as part of the Sloan Digital Sky Survey III (SDSS III), will revolutionize
our understanding of kinematical and chemical enrichment histories of all Galactic stellar populations. The instrument,
currently in fabrication, will be housed in a separate building adjacent to the 2.5 m SDSS telescope and fed light via
approximately 45-meter fiber runs from the telescope. The instrument design includes numerous technological
challenges and innovations including a gang connector that allows simultaneous connection of all fibers with a single
plug to a telescope cartridge that positions the fibers on the sky, numerous places in the fiber train in which focal ratio
degradation must be minimized, a large (290 mm x 475 mm elliptically-shaped recorded area) mosaic-VPH, an f/1.4 sixelement
refractive camera featuring silicon and fused silica elements with diameters as large as 393 mm, three near-within a custom, LN2-cooled, stainless steel vacuum cryostat with dimensions 1.4 m x 2.3 m x 1.3 m.
KEYWORDS: Astronomy, Telescopes, Software development, Spectroscopy, Observatories, Calibration, Astrophysics, Data acquisition, Computing systems, Signal to noise ratio
Astronomy is changing. Large projects, large collaborations, and large budgets are becoming the norm. The
Sloan Digital Sky Survey (SDSS) is one example of this new astronomy, and in operating the original survey, we
put in place and learned many valuable operating principles. Scientists sometimes have the tendency to invent
everything themselves but when budgets are large, deadlines are many, and both are tight, learning from others
and applying it appropriately can make the difference between success and failure. We offer here our experiences
well as our thoughts, opinions, and beliefs on what we learned in operating the SDSS.
The Apache Point Observatory 3.5-meter telescope is a working model of a modern mid-sized telescope used primarily on a shared-night, remote-observing basis. After a decade of successful remote operation and scientific accomplishments, the Astrophysical Research Consortium, builder and owner of the telescope, is examining the role by which this university-owned instrument can best serve its constituency and astronomy at large in the coming years. Various "niche" scientific capabilities are described for the telescope, including fast-response observations of transient phenomena, synoptic observing programs, reactive queue-scheduled observations, temporal study programs, plus being a capable test bed for new instruments. While specialized uses of the telescope offer potential for major scientific discoveries, traditional observing capabilities need to be sustained for the ongoing and future research programs for the majority of the consortium astronomers and students, a large and diverse community. Finding an appropriate balance between the "unique and specialized" versus the "bread-and-butter" observing models is discussed, as is the role hands-on remote observing can serve to support the various operational models.
The "new-technology" 3.5-meter telescope at Apache Point Observatory has been in routine operations since 1994. Designed to enable nearly full remote operation via the Internet, remote use of the telescope comprises two-thirds cf all observing. Rapid instrument change capabilities and flexible scheduling allow for some optimized science utilization. Several science programs can share the telescope on a given night, using more than one scientific instrument. Remote users can also collaboratively use the telescope simultaneously from different geographical locations. Synoptic observing programs and rapid-response observations are routinely accommodated. More than two hundred observers have used the telescope remotely, and by the end of I 997 more than 60 scientific publications based on telescope data have appeared in the journals. Several scenarios for operating the telescope have been explored. The current scheme is to schedule the telescope by quarters based on prioritized proposals submitted by the consortium member institutions. Except for short synoptic observations and targets of opportunity, each night is divided into halves. These half-night blocks provide adequate time on target plus calibration time, and provide simplification ofthe scheduling process which is done manually. Enhancements to telescope performance and efficiency are underway, which will provide broader scientific potential and support more exotic scheduling and operational paradigms. "Remote" queue and adaptive scheduling are conceivable, and the use of existing "Al-assisted" scheduling aides is also under consideration. Keywords: remote observing, Internet, 3.5-meter telescope, Astrophysical Research Consortium, ARC, Apache Point Observatory
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