SDSS Telescope. View of the main telescope of the Sloan Digital Sky Survey (SDSS). The telescope is situated at the Apache Point observatory, Sacramento Mountains, New Mexico, USA. The site is approximately 2789 metres above sea level. The telescope was specially designed to create a map of the sky. The telescope's camera uses electronic sensors to turn light into a stream of digitised data. The telescope also uses two spectrographs, instruments that probe the composition and distance of celestial objects. SDSS aims to map a quarter of the entire sky determining the position and absolute brightness of more than 100 million celestial objects.