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Sky coverage estimates for adaptive optics systems from computations in Zernike space

Clare, Richard M. and Ellerbroek, Brent L. (2006) Sky coverage estimates for adaptive optics systems from computations in Zernike space. Journal of the Optical Society of America A, 23 (2). pp. 418-426. ISSN 1084-7529.

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A sky coverage model for laser guide star adaptive optics systems is proposed. The atmosphere is considered to consist of a finite number of phase screens, which are defined by Zernike basis polynomials, located at different altitudes. These phase screens are transformed to the aperture plane, where they are converted to laser and natural guide star wavefront sensing measurements. These transformations incorporate the cone effect due to guide stars at finite heights, anisoplanatism due to guide stars off axis with respect to the science object, and adaptive optics systems with multiple guide stars. The wavefront error is calculated tomographically with minimum variance estimators derived from the transformation matrices and the known statistical properties of the atmosphere. This sky coverage model provides fast Monte Carlo simulations over random natural guide star configurations, irrespective of telescope diameter. The Monte Carlo simulations outlined show that inclusion of a finite outer scale for the atmosphere significantly reduces the median wavefront error, that increasing the number of laser guide stars in the asterism reduces the median wavefront error, and that a larger natural guide star patrol field provides a smaller median wavefront error when there is a low star density in the field.

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Additional Information:© 2006 Optical Society of America. Received May 19, 2005; accepted July 26, 2005. This paper was prepared as part of the work of the Thirty Meter Telescope (TMT) Project. TMT is a partnership of the Association of Universities for Research in Astronomy (AURA), the Association of Canadian Universities for Research in Astronomy (ACURA), the California Institute of Technology, and the University of California. The partners gratefully acknowledge the support of the Gordon and Betty Moore Foundation, the U.S. National Science Foundation (NSF), the National Research Council of Canada, the Natural Sciences and Engineering Research Council of Canada, and the Gemini Partnership. The New Initiatives Office is a partnership between two divisions of the AURA; the National Optical Astronomy Observatory (NOAO) and the Gemini Observatory. NOAO is operated by AURA under cooperative agreement with the NSF. The Gemini Observatory is operated by AURA under a cooperative agreement with the NSF on behalf of the Gemini partnership: the NSF (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).
Subject Keywords:adaptive optics; wave-front sensing
Issue or Number:2
Record Number:CaltechAUTHORS:CLAjosaa06
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5760
Deposited By: Lindsay Cleary
Deposited On:01 Nov 2006
Last Modified:02 Oct 2019 23:26

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