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A near-infrared pyramid wavefront sensor for Keck adaptive optics: real-time controller

Cetre, Sylvain and Guyon, Olivier and Bond, Charlotte and Chun, Mark and Mawet, Dimitri and Wizinowich, Peter and Lockhart, Charles and Goebel, Sean and Wetherell, Ed (2018) A near-infrared pyramid wavefront sensor for Keck adaptive optics: real-time controller. In: Adaptive Optics Systems VI. Proceedings of SPIE. No.10703. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 1070339. ISBN 9781510619593.

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A new real-time control system will be implemented within the Keck II adaptive optics system to support the new near-infrared pyramid wavefront sensor. The new real-time computer has to interface with an existing, very productive adaptive optics system. We discuss our solution to install it in an operational environment without impacting science. This solution is based on an independent SCExAO-based pyramid wavefront sensor realtime processor solution using the hardware interfaces provided by the existing Keck II real-time controller. We introduce the new pyramid real-time controller system design, its expected performance, and the modification of the operational real-time controller to support the pyramid system including interfacing with the existing deformable and tip-tilt mirrors. We describe the integration of the Saphira detector-based camera and the Boston Micromachines kilo-DM in this new architecture. We explain the software architecture and philosophy, the shared memory concept and how the real-time computer uses the power of GPUs for adaptive optics control. We discuss the strengths and weaknesses of this architecture and how it can benefit other projects. The motion control of the devices deployed on the Keck II adaptive optics bench to support the alignment of the light on the sensors is also described. The interfaces, developed to deal with the rest of the Keck telescope systems in the observatory distributed system, are reviewed. Based on this experience, we present which design ideas could have helped us integrate the new system with the previous one and the resultant performance gains.

Item Type:Book Section
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URLURL TypeDescription
Guyon, Olivier0000-0002-1097-9908
Mawet, Dimitri0000-0002-8895-4735
Wizinowich, Peter0000-0002-1646-442X
Additional Information:© 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). The near-infrared PWS is supported by the National Science Foundation under Grant No. AST-1611623. The fiber injection unit is supported by the Heising-Simons Foundation. The PWS camera was provided by Don Hall as part of his National Science Foundation funding under Grant No. ASF-1106391. We would like to acknowledge the technical contributions of Kevin Tsubota, Sam Ragland, Jason Chin, Jon Chock at WMKO, Eric Warmbier at IfA, Nemamja Jovanovic, Jacques-Robert Delorme at Caltech, the SCExAO team at Subaru and Frantz Martinache at Observatoire de la Cote d’Azur. Finally, we would like to thank Accelerate Diagnostics for providing the first GPU used in the RTC. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Group:Astronomy Department
Funding AgencyGrant Number
Heising-Simons FoundationUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:Real-Time Control, Pyramid Wavefront Sensor, Adaptive Optics
Series Name:Proceedings of SPIE
Issue or Number:10703
Record Number:CaltechAUTHORS:20180712-154055689
Persistent URL:
Official Citation:Sylvain Cetre, Olivier Guyon, Charlotte Bond, Mark Chun, Dimitri Mawet, Peter Wizinowich, Charles Lockhart, Sean Goebel, Ed Wetherell, "A near-infrared pyramid wavefront sensor for Keck adaptive optics: real-time controller", Proc. SPIE 10703, Adaptive Optics Systems VI, 1070339 (11 July 2018); doi: 10.1117/12.2311781;
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87813
Deposited By: George Porter
Deposited On:13 Jul 2018 16:19
Last Modified:15 Nov 2021 20:52

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