The Sloan Digital Sky Survey

The 2.5-meter Sloan Foundation Telescope was constructed for the purpose of creating the most detailed three-dimensional survey of the sky to date.  The telescope is capable of measuring the spectra of 640 objects at a time.  In its first eight years of operation it measured the spectra of 930,000 galaxies, 120,000 quasars, and 225,000 stars.  The most recent map of the galaxies, showing filaments and voids is shown below.

Above: The 2.5-meter Sloan Foundation Telescope at Apache Point Observatory. Image courtesy of the Sloan Digital Sky Survey. Further information is available at http://www.sdss.org/.   Left: SDSS Map of 930,000 Galaxies, reaching out about 2 billion light years. Color indicates age with redder galaxies composed of older stars.  Blank areas are due to dust in our own galaxy.  Image courtesy of M. Blanton and The Sloan Digital Sky Survey.