The Gemini Planet Imager: First Light And Commissioning

The Gemini Planet Imager (GPI) is a facility extreme-AO high-contrast instrument - optimized solely for study of faint companions - on the Gemini telescope. It combines a high-order MEMS AO system (1493 active actuators), an apodized-pupil Lyot coronagraph, a high-accuracy IR post-coronagraph wavefront sensor, and a near-infrared integral field spectrograph. GPI incorporates several other novel features such as ultra-high quality optics, a spatially-filtered wavefront sensor, and new calibration techniques. GPI had first light in November 2013. This paper presnets results of first-light and performance verification and optimization and shows early science results including extrasolar planet spectra and polarimetric detection of the HR4696A disk. GPI is now achieving contrasts approaching 10(-6) at 0.5" in 30 minute exposures