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Sloan Digital Sky Survey: Overview

The Sloan Digital Sky Survey (SDSS) is the most comprehensive survey of the sky yet undertaken. Begun in April 2000, the survey will map in detail one-sixth of the entire sky when completed in June 2005, determining the positions, brightnesses, and colors of nearly 100 million celestial objects (mostly galaxies as well as stars in our own galaxy). It will also measure the distances (redshifts) to roughly 600,000 galaxies and nearly 100,000 quasars.

The SDSS uses a dedicated, wide-field 2.5-meter telescope, along with a smaller 20-inch telescope to monitor standard stars. The main telescope is outfitted with a multi-CCD imaging camera covering 5 optical passbands and with two multi-fiber spectrographs that allow us to simultaneously measure spectra (and obtain redshifts) for 640 objects.

The SDSS addresses fundamental questions about how structure forms in the Universe, and about the detailed properties of galaxies, quasars, and stars. Mapping the large-scale distribution of galaxies, which form patterns such as voids, sheets, and filaments, constrains theories of how galaxies form and provides information on the density of dark matter in the Universe.

The Sloan Digital Sky Survey (SDSS) is a joint project of The University of Chicago, Fermilab, the Institute for Advanced Study, the Japan Participation Group, The Johns Hopkins University, the Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, the University of Pittsburgh, Princeton University, the United States Naval Observatory, and the University of Washington. Funding for the project has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Aeronautics and Space Administration, the National Science Foundation, the U.S. Department of Energy, the Japanese Monbukagakusho, and the Max Planck Society. Apache Point Observatory, site of the SDSS telescopes, is operated by the Astrophysical Research Consortium (ARC).

SDSS Science Center

The SDSS Science Center, a component of the Structures/Dark Energy MRC of the Center for Cosmological Physics at the University of Chicago, aims to facilitate SDSS-related research at Chicago and in the broader collaboration and to promote outreach using the SDSS dataset. For more information, see SDSS science projects we're involved in, associated personnel, publications, visitors, and events.

To find out more about the SDSS, visit the SDSS Public Website. For a technical description of the project, see the SDSS Technical Information page. You can interactively browse the digital sky at the SDSS SkyServer. The SDSS data is periodically released to the public; to access the data, go to the SDSS Archive.

This site was last updated on 18 October 2002. Send Web-related comments and questions to