The concept design of the Cornell Caltech Atacama Telescope mount

The Cornell Caltech Atacama Telescope(CCAT) is a 25m far infrared telescopein the conceptual designphase. Its primary mirroris composed of a set of panels supported by a space truss. The primary and secondary mirrorarrangement resembles the reflector and quadrapod arrangement seen in many radio telescopes, but with shallower primary mirrorgeometry. In addition, the optical layout calls for a close spacing between the tertiary mirrorand the Nasmyth and bent Cassegrain instruments. The mount design is driven by the spacing of the optical elements, the presence of the Nasmyth and bent Cassegrain ports, and the size of the primary mirror truss. This paper examines the mechanical and control system designsolutions provided in response to the challenges posed by the optical requirements. These solutions include tradeoffs in structure, drive, and control system design.