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Proceedings Paper

Altair performance and upgrades
Author(s): Olivier Lai; Jean-Pierre Véran; Glen Herriot; John White; Jesse Ball; Chad Trujillo
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Paper Abstract

Altair is the facility single conjugate AO system for Gemini North. Although it has been in operation for more than 10 years (and upgraded to LGS in 2007), Altair's performance is degraded by three main issues: vibrations of the telescope and instrument support structure, spatial aliasing on centroid offsets from the M2 support structure print-through on the optical surface and static non-common path aberrations. Monte-Carlo simulations can reproduce the behavior of Altair when including these three effects and they are roughly of the same order of magnitude. Solutions or mitigations are being investigated to overcome these nefarious effects and restore Altair's performance to its nominal level. A simplex algorithm as well as a phase diversity approach are being investigated to measure and correct for static aberrations. A high accuracy phase map of the M2 print-through has been obtained and is being used to calibrate and/or filter centroids affected by aliasing. A new real time computer is under consideration, to be able to handle more advanced controllers, especially notch filters to combat vibrations. In this paper we will report on the various simulations and on-sky results of this rejuvenation of one of Gemini's workhorse instruments.

Paper Details

Date Published: 21 July 2014
PDF: 13 pages
Proc. SPIE 9148, Adaptive Optics Systems IV, 914838 (21 July 2014); doi: 10.1117/12.2056948
Show Author Affiliations
Olivier Lai, Gemini Observatory (United States)
Subaru Telescope, National Astronomical Observatory of Japan (United States)
Jean-Pierre Véran, NRC - Herzburg Institute of Astrophysics (Canada)
Glen Herriot, NRC - Herzburg Institute of Astrophysics (Canada)
John White, Gemini Observatory (United States)
Jesse Ball, Gemini Observatory (United States)
Chad Trujillo, Gemini Observatory (United States)

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

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