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Proceedings Paper

Evaluating sky coverage for the NFIRAOS tip/tilt control architecture
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Paper Abstract

The Narrow Field Infrared Adaptive Optics System (NFIRAOS) is the first light Laser Guide Star (LGS) Multi-Conjugate Adaptive Optics (MCAO) system for TMT. NFIRAOS needs to correct 2-axis tip/tilt jitter disturbances, including both telescope vibration and atmospheric tip/tilt, to a residual of 2 milli-arcsecond (mas) RMS with 50% sky coverage at the Galactic pole. NFIRAOS will utilize multiple infrared tip/tilt sensors, as sky coverage benefits greatly from wavefront sensing in the near IR where guide star densities are greater and the NFIRAOS AO system "sharpens" the guide star images. NFIRAOS will also utilize type II woofer-tweeter control to correct tip/tilt jitter. High amplitude, low bandwidth errors are corrected by a tip/tilt platform (woofer), whereas the low amplitude, high bandwidth disturbances are corrected by the deformable mirrors. A prototype development effort for the relatively large, massive DM tip/tilt stage is now underway. Detailed Monte Carlo simulations of the complete architecture indicate that the sky coverage and tip/tilt control requirement for NFIRAOS can be met, with some margin available for stronger input disturbances or shortfalls in component performance.

Paper Details

Date Published: 15 July 2008
PDF: 9 pages
Proc. SPIE 7015, Adaptive Optics Systems, 70155X (15 July 2008); doi: 10.1117/12.787975
Show Author Affiliations
Lianqi Wang, California Institute of Technology (United States)
Brent Ellerbroek, California Institute of Technology (United States)
Jean-Pierre Véran, Herzberg Institute of Astrophysics (Canada)
Jean-Christophe Sinquin, CILAS (France)


Published in SPIE Proceedings Vol. 7015:
Adaptive Optics Systems
Norbert Hubin; Claire E. Max; Peter L. Wizinowich, Editor(s)

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