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Proceedings Paper

Design, development, and testing of the DCT Cassegrain instrument support assembly
Author(s): Thomas A. Bida; Edward W. Dunham; Ralph A. Nye; Tomas Chylek; Richard C. Oliver
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Paper Abstract

The 4.3m Discovery Channel Telescope delivers an f/6.1 unvignetted 0.5° field to its RC focal plane. In order to support guiding, wavefront sensing, and instrument installations, a Cassegrain instrument support assembly has been developed which includes a facility guider and wavefront sensor package (GWAVES) and multiple interfaces for instrumentation. A 2-element, all-spherical, fused-silica corrector compensates for field curvature and astigmatism over the 0.5° FOV, while reducing ghost pupil reflections to minimal levels. Dual roving GWAVES camera probes pick off stars in the outer annulus of the corrected field, providing simultaneous guiding and wavefront sensing for telescope operations. The instrument cube supports 5 co-mounted instruments with rapid feed selection via deployable fold mirrors. The corrected beam passes through a dual filter wheel before imaging with the 6K x 6K single CCD of the Large Monolithic Imager (LMI). We describe key development strategies for the DCT Cassegrain instrument assembly and GWAVES, including construction of a prime focus test assembly with wavefront sensor utilized in fall 2011 to begin characterization of the DCT primary mirror support. We also report on 2012 on-sky test results of wavefront sensing, guiding, and imaging with the integrated Cassegrain cube.

Paper Details

Date Published: 17 September 2012
PDF: 16 pages
Proc. SPIE 8444, Ground-based and Airborne Telescopes IV, 844451 (17 September 2012); doi: 10.1117/12.926320
Show Author Affiliations
Thomas A. Bida, Lowell Observatory (United States)
Edward W. Dunham, Lowell Observatory (United States)
Ralph A. Nye, Lowell Observatory (United States)
Tomas Chylek, Lowell Observatory (United States)
Richard C. Oliver, Lowell Observatory (United States)

Published in SPIE Proceedings Vol. 8444:
Ground-based and Airborne Telescopes IV
Larry M. Stepp; Roberto Gilmozzi; Helen J. Hall, Editor(s)

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