The conceptual design of the Giant Magellan Telescope has four wavefront sensors used to maintain the shape and alignment of the segmented primary and secondary mirrors. In this paper, we show that by reading the sensors at 200 Hz, we can also compensate for low altitude turbulence. As a result, there is a large improvement in image quality, even at visible wavelengths, over the entire science field of view of the telescope. A minimum-variance reconstructor is presented that takes slope measurements from four stars of arbitrary location and magnitude and produces the optimal adaptive secondary mirror commands. The performance of the adaptive optics system in this mode is simulated using YAO, an end-to-end simulation tool. We present the results of trade studies performed to optimize the science return of the telescope.

Date Published: 21 July 2014
PDF: 12 pages
Proc. SPIE 9148, Adaptive Optics Systems IV, 914813 (21 July 2014); doi: 10.1117/12.2054154

Published in SPIE Proceedings Vol. 9148:
Adaptive Optics Systems IV
Enrico Marchetti; Laird M. Close; Jean-Pierre Véran, Editor(s)