Sloan Digital Survey Satiates Skywatchers

摘要

The hottest newcomer in this period is the second data release from the Sloan Digital Sky Survey (SDSS), which is the most ambitious sky survey ever undertaken. It is set to change forever our knowledge of the large-scale structure of the universe. The survey is in the process of mapping one-quarter of the whole sky, and it has so far observed 180 million objects, to determine their positions and brightnesses. SDSS is a consortium of 300 scientists and 23 participating institutions. The survey uses a dedicated 2.5-m wide field telescope at Apache Point Observatory, New Mexico. Astronomers have leapt on Hot Paper #4 because it accompanies the second release of data to the public, on March 15, 2004. This release has positions and imaging data from one-twelfth of the sky, scooping 88 million objects, along with more than a third of a million spectra of galaxies, quasars, and stars. The survey is accompanied by a marvelous array of common user tools for teasing out data in a multitude of ways. For example, in this release there are spectra of 35,000 stars in the Milky Way. For this sample we now have stellar radial with an accuracy of ～5 km/s, and these can be used for modeling stellar motions in the Galaxy.