Panel options for large precision radio telescopes

The Cornell Caltech Atacama Telescope (CCAT) is a 25 in diameter telescope that will operate at wavelengths as short as 200 microns. CCAT will have active surface control to correct for gravitational and thermal distortions in the reflector support structure. The accuracy and stability of the reflector panels Lire critical to meeting the 10 micron HWFE (half wave front error) for the whole system. A system analysis based upon a versatile generic panel design has been developed and applied to numerous possible panel configurations. The error analysis includes the manufacturing errors plus the distortions from gravity, wind and thermal environment. The system performance as a function of panel size and construction material is presented. A compound panel approach is also described in which the reflecting Surface is provided by tiles mounted oil thermally stable and stiff sub-frames, This approach separates the function of providing ail accurate reflecting Surface from the requirement for a stable structure that is attached to the reflector Support structure on three computer controlled actuators. The analysis indicates that there are several compound panel coil figurations that will easily meet the stringent CCAT requirements.