Astronomical Adaptive Optics with MEMS Deformable Mirrors Kaie Morzinski, CfAO Micro-electro-mechanical systems (MEMS) deformable mirrors are compact and economical, valuable for a range of adaptive optics (AO) applications from vision science to communications. With thousands of hysteresis-free actuators, they are compelling for astronomical AO systems operating in new regimes. These include (1) extreme AO for high-contrast imaging, (2) open-loop control for novel system architectures, and (3) visible-wavelength AO. I will talk about my laboratory and telescope experiments with MEMS deformable mirrors. This encompasses aspects of reliability of MEMS actuators; funtionality for controlling Kolmogorov turbulence; and visible-light open-loop MEMS AO at Lick Observatory.