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Proceedings Paper

The Giant Magellan Telescope phasing system
Author(s): Antonin H. Bouchez; Brian A. McLeod; D. Scott Acton; Srikrishna Kanneganti; Edward J. Kibblewhite; Stephen A. Shectman; Marcos A. van Dam
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Paper Abstract

The 25 m Giant Magellan Telescope consists of seven circular 8.4 m primary mirror segments with matching segmentation of the Gregorian secondary mirror. Achieving the diffraction limit in the adaptive optics observing modes will require equalizing the optical path between pairs of segments to a small fraction of the observing wavelength. This is complicated by the fact that primary mirror segments are separated by up to 40 cm, and composed of borosilicate glass. The phasing system therefore includes both edge sensors to sense high-frequency disturbances, and wavefront sensors to measure their long-term drift and sense atmosphere-induced segment piston errors. The major subsystems include a laser metrology system monitoring the primary mirror segments, capacitive edge sensors between secondary mirror segments, a phasing camera with a wide capture range, and an additional sensitive optical piston sensor incorporated into each AO instrument. We describe in this paper the overall phasing strategy, controls scheme, and the expected performance of the system with respect to the overall adaptive optics error budget. Further details may be found in specific papers on each of the subsystems.

Paper Details

Date Published: 13 September 2012
PDF: 9 pages
Proc. SPIE 8447, Adaptive Optics Systems III, 84473S (13 September 2012); doi: 10.1117/12.927163
Show Author Affiliations
Antonin H. Bouchez, Giant Magellan Telescope Organization Corp. (United States)
Brian A. McLeod, Smithsonian Astrophysical Observatory (United States)
D. Scott Acton, Ball Aerospace & Technologies Corp. (United States)
Srikrishna Kanneganti, Smithsonian Astrophysical Observatory (United States)
Edward J. Kibblewhite, The Univ. of Chicago (United States)
Stephen A. Shectman, Carnegie Observatories (United States)
Marcos A. van Dam, Flat Wavefronts (New Zealand)

Published in SPIE Proceedings Vol. 8447:
Adaptive Optics Systems III
Brent L. Ellerbroek; Enrico Marchetti; Jean-Pierre Véran, Editor(s)

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