Use of Accelerometers to Reduce Dynamic Range Requirements in an Adaptive Optics System

In many instances, mechanical vibrations, not atmospherics, are the dominant contributors to time varying optical tilts affecting both astronomical and terrestrial observations. We used a pair of inexpensive micromachined accelerometers placed on the secondary mirror mount of a 12" telescope, inferring angular deviations from twice temporally integrated acceleration signals. We then applied this result with appropriate gain to a feed-forward tip/tilt mirror correction loop with good results.