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Proceedings Paper

Current status of the HETDEX fiber optic support system
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Paper Abstract

The Hobby-Eberly Telescope Dark Energy eXperiment [HETDEX] will employ over 43,000 optical fibers to feed light to 192 Visible Integral-Field Replicable Unit Spectrographs [VIRUS]. Each VIRUS instrument is fed by 224 fibers. To reduce cost, the spectrographs are combined into pairs; thus, two bundles of 224 fibers are combined into a single Integral Field Unit [IFU] of 448 fibers. On the input end the fibers are arranged in a square 'dense-pack' array at the HET focal surface. At the output end the IFU terminates in two separate linear arrays which provide entry slits for each spectrometer unit. The IFU lengths must be kept to an absolute minimum to mitigate losses; however, consideration of overall project cost and duration of the science mission have resulted in the generation of two competing concepts. Multiple axes of motion are imposed on the IFUs as they span the shortest distance from the focal surface to each VIRUS unit. Arranging and supporting 96 IFUs, that have a total mass over 450 kg, in a manner that is compatible with these complex translations, together with the management of accompanying forces on the tracking mechanism of the HET, presents a significant technical challenge, which is further compounded by wind buffeting. The longer IFU concept is favored due to overall project cost, but requires tests to assure that the fibers can withstand forces associated with a height differential of 16.25 meters without FRD losses or breakage.

Paper Details

Date Published: 9 July 2008
PDF: 12 pages
Proc. SPIE 7014, Ground-based and Airborne Instrumentation for Astronomy II, 70147L (9 July 2008); doi: 10.1117/12.790256
Show Author Affiliations
John M. Good, The Univ. of Texas McDonald Observatory (United States)
Gary J. Hill, The Univ. of Texas McDonald Observatory (United States)
Nicholas T. Mollison, The University of Texas at Austin (United States)
Brian L. Vattiat, The Univ. of Texas McDonald Observatory (United States)
Jeremy D. Murphy, The Univ. of Texas McDonald Observatory (United States)
Andreas Klez, Astrophysikalisches Institut Potsdam (Germany)
Martin M. Roth, Astrophysikalisches Institut Potsdam (Germany)
Phillip J. MacQueen, The Univ. of Texas McDonald Observatory (United States)
Marc D. Rafal, The Univ. of Texas McDonald Observatory (United States)
Richard D. Savage, The Univ. of Texas McDonald Observatory (United States)
Michael P. Smith, The Univ. of Texas McDonald Observatory (United States)
Amanda J. Bayless, The Univ. of Texas McDonald Observatory (United States)


Published in SPIE Proceedings Vol. 7014:
Ground-based and Airborne Instrumentation for Astronomy II
Ian S. McLean; Mark M. Casali, Editor(s)

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