Adaptive Optics for Extremely Large Telescopes 4 – Conference Proceedings

A multi-conjugate adaptive optics (MCAO) system for solar observations has been set up at the 1.6-meter clearaperture New Solar Telescope (NST) in Big Bear Lake, California. Being a pathnder to address fundamentaldesign questions in solar MCAO experimentally, the system is purposely exible. We deploy three deformablemirrors (DMs). One of which is conjugate to the telescope pupil, and the other two to distinct higher altitudes.The pupil DM can be either placed into a pupil image up- or downstream of the high-altitude DMs. Thehigh-altitude DMs can be separately and quickly conjugated to various altitudes between 2 and 8 km. ThreeShack-Hartmann wavefront sensor units are available, one for low-order, multi-directional sensing and two highorderon-axis sensing of which one is used at a time. The exibility of the setup allows us to experimentallystudy the various sequencings of DMs and WFSs, which are hard to simulate conclusively. We report on thepreliminary results and summarize the design and the conguration options of the MCAO system at Big BearSolar Observatory (BBSO).