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The Gemini Planet Imager (GPI) is a next-generation, facility instrumentcurrently being commissioned at the Gemini South observatory. GPI combines anextreme adaptive optics system and integral field spectrograph (IFS) with anapodized-pupil Lyot coronagraph (APLC) producing an unprecedented capabilityfor directly imaging and spectroscopically characterizing extrasolar planets.GPI's operating goal of $10^{-7}$ contrast requires very precise alignmentsbetween the various elements of the coronagraph (two pupil masks and one focalplane mask) and active control of the beam path throughout the instrument.Here, we describe the techniques used to automatically align GPI and maintainthe alignment throughout the course of science observations. We discuss theparticular challenges of maintaining precision alignments on a Cassegrainmounted instrument and strategies that we have developed that allow GPI toachieve high contrast even in poor seeing conditions.

Automated Alignment and On-Sky Performance of the Gemini Planet Imager Coronagraph