Share Email Print

Proceedings Paper

The Giant Magellan Telescope phasing strategy and performance
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

The 25.4m Giant Magellan Telescope (GMT) consists of seven 8.4 m primary mirror (M1) segments with matching segmentation of the Gregorian secondary mirror (M2). When operating the GMT in the diffraction-limited Adaptive Optics (AO) modes, using the Adaptive Secondary Mirror (ASM), the M1-M2 pairs of segments must be phased to a small fraction of the observing wavelength. To achieve this level of correction across the scientific field of view (<90” in diameter), the phasing system relies on multiple (up to four) natural guide-star probes deployed across the field of view (from 6’ to 10’ from the center of the field) measuring at slow rates (~0.033 Hz) segment phase piston in the infrared and low-order field-dependent phase aberrations in the visible. This paper describes the overall phasing strategy and requirements when operating in the Natural Guide-star AO (NGAO) and the Laser Tomography AO (LTAO) modes. We will also present a first evaluation of segment piston error induced by wind buffeting on the telescope structure. Wind loads have been computed for different observatory configurations using Computational Fluid Dynamics (CFD) simulations. This analysis showcases the GMT Dynamic Optical Simulation (DOS) environment which integrates the optical and structural dynamic models of the GMT with the Fourier optics models of AO and phasing sensors.

Paper Details

Date Published: 6 July 2018
PDF: 11 pages
Proc. SPIE 10700, Ground-based and Airborne Telescopes VII, 107000N (6 July 2018); doi: 10.1117/12.2312236
Show Author Affiliations
F. Quirós-Pacheco, GMTO Organization (United States)
David Schwartz, GMTO Organization (United States)
Kaushik Das, GMTO Organization (United States)
Rodolphe Conan, GMTO Organization (United States)
Antonin H. Bouchez, GMTO Organization (United States)
Ben Irarrazaval, GMTO Organization (United States)
Brian A. McLeod, Smithsonian Astrophysical Observatory (United States)

Published in SPIE Proceedings Vol. 10700:
Ground-based and Airborne Telescopes VII
Heather K. Marshall; Jason Spyromilio, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?