Sloan Digital Sky Survey 2.5-m telescope: light baffles

The Sloan Digital Sky Survey 2.5-m telescope is unique with a 3 degrees field of view at f/5. The two-mirror optical design includes two transmitting correcting elements To avoid excessive central obstruction of the entrance pupil, a conical baffle is necessary in addition to the usual primary and secondary baffles. This conical baffle is suspended approximately midway between the primary and secondary mirrors. In addition, an exterior close-fitting wind and light baffle, not found on most modern telescopes, blocks rays at large angles from the field of view.