Taming the 1.2 m Telescope

Abstract : Achievable residual jitter on the 1.2 m telescope at MSSS has historically been limited in moderate wind conditions due to the combination of the dynamics associated with the twin telescopes on the common declination axis shaft and the related control system behavior. The lightly damped, low frequency fundamental vibration mode shape of the telescopes rotating out of phase on the common declination axis shaft severely degraded the performance of the prior controllers. The relatively poor historic performance was due to a combination of the low error rejection of external disturbances, and the controller exciting the mode. The new control architecture described in this paper has made it possible to achieve greatly improved pointing performance.