Optical Design And Instrumentation Of The Keck Observatory

The Keck Observatory Ten Meter Telescope has a Ritchey-Chretien optical design which maximizes the field of view for an f/15 focus at about 20 arcminutes. An f/25 infrared focus provides a 9 arcminute field. The optical design and the optical tolerances will provide 0.5 arcsecond images (80% enclosed energy diameter) over these fields of view. This is equivalent to 0.25 arcsecond FWHM seeing conditions. Instrumentation is designed to allow for rapid, semi-automatic instrument exchanges. At major foci, the instruments will be contained in interchangeable modules having a common weight and center of gravity that attach kinematically to the telescope.