20 July 2010 Gemini Planet Imager coronagraph testbed results
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The Gemini Planet Imager (GPI) is an extreme AO coronagraphic integral field unit YJHK spectrograph destined for first light on the 8m Gemini South telescope in 2011. GPI fields a 1500 channel AO system feeding an apodized pupil Lyot coronagraph, and a nIR non-common-path slow wavefront sensor. It targets detection and characterizion of relatively young (<2GYr), self luminous planets up to 10 million times as faint as their primary star. We present the coronagraph subsystem's in-lab performance, and describe the studies required to specify and fabricate the coronagraph. Coronagraphic pupil apodization is implemented with metallic half-tone screens on glass, and the focal plane occulters are deep reactive ion etched holes in optically polished silicon mirrors. Our JH testbed achieves H-band contrast below a million at separations above 5 resolution elements, without using an AO system. We present an overview of the coronagraphic masks and our testbed coronagraphic data. We also demonstrate the performance of an astrometric and photometric grid that enables coronagraphic astrometry relative to the primary star in every exposure, a proven technique that has yielded on-sky precision of the order of a milliarsecond.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Anand Sivaramakrishnan, Anand Sivaramakrishnan, Rémi Soummer, Rémi Soummer, Ben R. Oppenheimer, Ben R. Oppenheimer, G. Lawrence Carr, G. Lawrence Carr, Jacob L. Mey, Jacob L. Mey, Doug Brenner, Doug Brenner, Charles W. Mandeville, Charles W. Mandeville, Neil Zimmerman, Neil Zimmerman, Bruce A. Macintosh, Bruce A. Macintosh, James R. Graham, James R. Graham, Les Saddlemyer, Les Saddlemyer, Brian Bauman, Brian Bauman, Alexis Carlotti, Alexis Carlotti, Laurent Pueyo, Laurent Pueyo, Peter G. Tuthill, Peter G. Tuthill, Christophe Dorrer, Christophe Dorrer, Robin Roberts, Robin Roberts, Alexandra Greenbaum, Alexandra Greenbaum, "Gemini Planet Imager coronagraph testbed results", Proc. SPIE 7735, Ground-based and Airborne Instrumentation for Astronomy III, 773586 (20 July 2010); doi: 10.1117/12.858623; https://doi.org/10.1117/12.858623


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