TY - CONF
T1 - Prototyping the GMT phasing camera with the Magellan AO system
AU - Kopon, Derek
AU - McLeod, Brian
AU - McCracken, Kenneth
AU - Van Dam, Marcos
AU - Bouchez, Antonin
AU - Conder, Alan
AU - Podgorski, William
AU - Catropa, Daniel
AU - McMuldroch, Stuart
AU - Close, Laird
AU - Males, Jared
AU - Morzinski, Katie
AU - Norton, Timothy
N1 - Funding Information:
This work was supported by the GMTO Corporation, a non-profit organization operated on behalf of an international consortium of universities and institutions: Astronomy Australia Ltd., the Australian National University, the Carnegie Institution for Science, Harvard University, the Korea Astronomy and Space Science Institute, The Sao Paolo Research Foundation, the Smithsonian Institution, The University of Texas at Austin, Texas A&M University, University of Arizona, and University of Chicago.
PY - 2015
Y1 - 2015
N2 - The future diffraction-limited performance of the 25.4 meter Giant Magellan Telescope (GMT) will rely on the active and adaptive wavefront sensing measurements made by the Acquisition, Guiding, and Wavefront Sensor (AGWS) currently being designed by SAO. One subsystem of the AGWS, the phasing camera, will be responsible for measuring the piston phase difference between the seven GMT primary/secondary segment pairs to 50 nm accuracy with full sky coverage using natural guide stars that are 6-10 arcmin off-axis while the on-axis light is used for science operations. The phasing camera will use a dispersed fringe sensor to measure the phase difference in rectangular subapertures spanning the gaps between adjacent mirror segments. The large gap between segments (>295 mm, compared to 3 mm for the Keck telescope) reduces the coherence of light across the subapertures, making this problem particularly challenging. In support of the AGWS phasing camera technical goals, SAO has undertaken a series of prototyping efforts at the Magellan 6.5 meter Clay telescope to demonstrate the dispersed fringe sensor technology and validate atmospheric models. Our latest on-sky test, completed in December 2015, employs a dual-band (I and J) dispersed fringe sensor. This prototype uses an adaptive optics corrected beam from the Magellan AO adaptive secondary system. The system operates both on-axis and 6 arcmin off-axis from the natural guide star feeding the MagAO wavefront sensor. This on-sky data will inform the development of the AGWS phasing camera design towards the GMT first light.
AB - The future diffraction-limited performance of the 25.4 meter Giant Magellan Telescope (GMT) will rely on the active and adaptive wavefront sensing measurements made by the Acquisition, Guiding, and Wavefront Sensor (AGWS) currently being designed by SAO. One subsystem of the AGWS, the phasing camera, will be responsible for measuring the piston phase difference between the seven GMT primary/secondary segment pairs to 50 nm accuracy with full sky coverage using natural guide stars that are 6-10 arcmin off-axis while the on-axis light is used for science operations. The phasing camera will use a dispersed fringe sensor to measure the phase difference in rectangular subapertures spanning the gaps between adjacent mirror segments. The large gap between segments (>295 mm, compared to 3 mm for the Keck telescope) reduces the coherence of light across the subapertures, making this problem particularly challenging. In support of the AGWS phasing camera technical goals, SAO has undertaken a series of prototyping efforts at the Magellan 6.5 meter Clay telescope to demonstrate the dispersed fringe sensor technology and validate atmospheric models. Our latest on-sky test, completed in December 2015, employs a dual-band (I and J) dispersed fringe sensor. This prototype uses an adaptive optics corrected beam from the Magellan AO adaptive secondary system. The system operates both on-axis and 6 arcmin off-axis from the natural guide star feeding the MagAO wavefront sensor. This on-sky data will inform the development of the AGWS phasing camera design towards the GMT first light.
KW - Active optics
KW - Adaptive optics
KW - Dispersed fringe sensor
KW - Giant Magellan Telescope
KW - Phasing
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U2 - 10.20353/K3T4CP1131566
DO - 10.20353/K3T4CP1131566
M3 - Paper
AN - SCOPUS:84994496289
T2 - 4th Adaptive Optics for Extremely Large Telescopes, AO4ELT 2015
Y2 - 26 October 2015 through 30 October 2015
ER -