The most complex digital imaging telescope ever developed for astronomy will catalog the position and brightness of more than 100 million stars, galaxies, and quasars. It will map one quarter of the sky and give us a three-dimensional picture of the universe through a volume a hundred times greater than anyone has explored before. The completed survey will contain about 15 trillion bytes, a volume of information rivaling the Library of Congress. The telescope has some unique features. Groups of charge coupled devices combined with colored filters give a five-color view of objects.
Spectrographic analysis gives information about the composition and distance of objects.
The telescope itself is very different in appearance than most. It is not housed in a domed building because differential heating in enclosed domes sets up air currents that blur images. The Sloan telescope is housed in a shed that is wheeled away during viewing. The telescope is surrounded by baffles that cut 90 percent of the wind but maintain a flow of constant-temperature air. The baffles, which are not physically attached to the telescope, also block stray light.