Performance criteria for the optical designs for VISTA

摘要

The Visible and Infra-red Survey Telescope for Astronomy, or VISTA, is a UK funded four metre class wide-field, infrared and optical survey telescope to be situated in Chile. The telescope, which can be regarded as a two-channel camera, provides a one-degree, infrared field and a two-degree, optical field. The project goal of low running costs requires minimal intervention by support staff. The optical configuration of the telescope must meet the scientific requirements while delivering a stable instrumental profile for the 12-year duration of the survey. Accurate calibration of throughput, image quality and field distortion will be essential to the photometric and astrometric quality of that survey. The process for selection of optical design options is described and discussed with particular reference to meeting the functional and performance requirements, determined from the scientific specification, and to achieving a predictable and reliable image quality. The practical limitations imposed by budgetary and operational requirements are assessed for their role as contributory design drivers.