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Sky coverage estimates for the natural guide star mode of the TMT facility AO system NFIRAOS

Ellerbroek, B. and Andersen, David (2008) Sky coverage estimates for the natural guide star mode of the TMT facility AO system NFIRAOS. In: Adaptive Optics Systems. Proceedings of SPIE. No.7015. Society of Photo-Optical Instrumentation Engineers , Bellingham, WA, Art. No. 70155W. ISBN 9780819472250. http://resolver.caltech.edu/CaltechAUTHORS:20181217-112623852

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Abstract

Although the TMT AO system NFIRAOS will operate primarily in a laser guidestar multi-conjugate AO mode, it will also provide a conventional natural guide star (NGS) mode for use on very narrow science fields containing a bright star and/or when laser propagation is prevented by thin cirrus clouds or other circumstances. The number of bright stars suitable for use with a high order AO system is limited, so we have performed a sky coverage analysis to determine the likelyhood of achieving a given Strehl ratio when observing a randomly selected science field. The results obtained are significantly better than for existing NGS AO systems, largely due to (i) the anticipated availability of large, high-speed detector arrays with sub-electron read noise, and (ii) the benign telescope windshake disturbances predicted for TMT. Order 60×60 wavefront sensing and correction is preferred to lower order AO compensation, and an H-band Strehl of 0.25 [0.50] is obtained with sky coverage of about 1.0 [0.1] per cent at the Galactic pole in median seeing. This level of performance will provide an important capability for TMT well into the life of the observatory.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.1117/12.788053DOIArticle
Additional Information:© 2008 Society of Photo-Optical Instrumentation Engineers. The authors gratefully acknowledge the support of the TMT partner institutions. They are the Association of Canadian Universities for Research in Astronomy (ACURA), the California Institute of Technology and the University of California. This work was supported as well by the Gordon and Betty Moore Foundation, the Canada Foundation for Innovation, the Ontario Ministry of Research and Innovation, the National Research Council of Canada, the Natural Sciences and Engineering Research Council of Canada, the British Columbia Knowledge Development Fund, the Association of Universities for Research in Astronomy (AURA) and the U.S. National Science Foundation. Additionally, Sean Adkins and Paul Jordan provided the information on the expected performance of future high-speed CCD arrays, and Jean-Pierre Véran assisted with the comparision of discrete- and continuous-time servo models.
Group:Thirty Meter Telescope
Funders:
Funding AgencyGrant Number
Association of Canadian Universities for Research in Astronomy (ACURA)UNSPECIFIED
CaltechUNSPECIFIED
University of CaliforniaUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Canada Foundation for InnovationUNSPECIFIED
Ontario Ministry of Research and InnovationUNSPECIFIED
National Research Council of CanadaUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
British Columbia Knowledge Development FundUNSPECIFIED
Association of Universities for Research in Astronomy (AURA)UNSPECIFIED
NSFUNSPECIFIED
Subject Keywords:Thirty Meter Telescope, Adaptive Optics, NFIRAOS, Real Time Controller
Record Number:CaltechAUTHORS:20181217-112623852
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20181217-112623852
Official Citation:B. Ellerbroek, David Andersen, "Sky coverage estimates for the natural guide star mode of the TMT facility AO system NFIRAOS," Proc. SPIE 7015, Adaptive Optics Systems, 70155W (15 July 2008); doi: 10.1117/12.788053
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91862
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:18 Dec 2018 19:40
Last Modified:18 Dec 2018 19:40

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