TY - CONF
T1 - Phasing the GMT with a next generation e-APD dispersed fringe sensor
T2 - 5th Adaptive Optics for Extremely Large Telescopes, AO4ELT 2017
AU - Kopon, Derek
AU - McLeod, Brian
AU - Bouchez, Antonin
AU - Catropa, Daniel
AU - Van Dam, Marcos A.
AU - McCracken, Ken
AU - McMuldroch, Stuart
AU - Podgorski, William
AU - D'Arco, Joseph
AU - Close, Laird
AU - Males, Jared
AU - Morzinski, Katie
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.
Publisher Copyright:
© 2017 Instituto de Astrofisica de Canarias. All rights reserved.
PY - 2017
Y1 - 2017
N2 - The GMT will be a 25.4-meter telescope consisting of 7 primary and secondary mirror segments that must be phased to within a fraction of an imaging wavelength in order to achieve diffraction limited performance. The need to use off-axis guide stars, coupled with the large (350 mm) segment gaps, makes the task of phasing the GMT uniquely challenging. To meet these requirements, the Acquisition, Guiding, and Wavefront Sensing system (AGWS) will use four J-band dispersed fringe sensors (DFS) to measure segment piston at each segment boundary. This DFS will use a novel array of doublet prisms, instead of grisms, to disperse segment boundary fringes with maximal throughput, minimal stray light, and no spurious diffractive orders. The DFS will also use a low noise SAPHIRA e-APD array reading out at ~100 Hz in order to freeze atmospheric turbulence in the segment boundary fringe images. We will test a prototype of this DFS on the Magellan Clay 6.5 meter telescope using an adaptive optics corrected beam from the MagAO system. We present the design of the next generation phasing prototype.
AB - The GMT will be a 25.4-meter telescope consisting of 7 primary and secondary mirror segments that must be phased to within a fraction of an imaging wavelength in order to achieve diffraction limited performance. The need to use off-axis guide stars, coupled with the large (350 mm) segment gaps, makes the task of phasing the GMT uniquely challenging. To meet these requirements, the Acquisition, Guiding, and Wavefront Sensing system (AGWS) will use four J-band dispersed fringe sensors (DFS) to measure segment piston at each segment boundary. This DFS will use a novel array of doublet prisms, instead of grisms, to disperse segment boundary fringes with maximal throughput, minimal stray light, and no spurious diffractive orders. The DFS will also use a low noise SAPHIRA e-APD array reading out at ~100 Hz in order to freeze atmospheric turbulence in the segment boundary fringe images. We will test a prototype of this DFS on the Magellan Clay 6.5 meter telescope using an adaptive optics corrected beam from the MagAO system. We present the design of the next generation phasing prototype.
KW - Active optics
KW - Adaptive optics
KW - Dispersed fringe sensor
KW - Giant magellan telescope
KW - Phasing
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M3 - Paper
AN - SCOPUS:85049317310
Y2 - 25 June 2017 through 30 June 2017
ER -