| | Encyclopedia article: Sloan Digital Sky Survey (Site not responding. Last check: 2007-10-08) |
 | | Named after the Alfred P. Sloan Foundation, it aims to map 25% of the sky and obtain observations on around 100 million objects. |
 | | It has redshift (additional info and facts about redshift) s for galaxies as far z=0.3 or 0.4, and has been involved in the detection of quasar (A starlike object that may send out radio waves and other forms of energy; large red shifts imply enormous recession velocities) s beyond a redshift 6. |
 | | Both spectra and images are available in this way, and interfaces are made very easy to use so that, for example, a full colour image of any region of the sky covered by an SDSS data release can be obtained just by providing the coordinates. |
| www.absoluteastronomy.com /encyclopedia/s/sl/sloan_digital_sky_survey.htm (403 words) |