Sloan Digital Sky Surveys

The SDSS-V Pioneering Panoptic Spectroscopy program started observing in October 2020, and consists of three surveys, known in SDSS-V terminology as mapper programs.

• Milky Way Mapper is a multi-object spectroscopic survey to obtain near-infrared and/or optical spectra of more than 4 million stars throughout the Milky Way and Local Group
• Local Volume Mapper is an optical, integral-field spectroscopic survey that will target the Milky Way, Small and Large Magellanic Clouds, and other Local Volume galaxies
• Black Hole Mapper is a multi-object spectroscopic survey that emphasizes optical spectra (often also with multiple epochs of spectroscopy) for more than 300,000 quasars

More information on SDSS-V and its mappers, including how to join SDSS-V, is available on the sdss5.org website.

After nearly a decade of design and construction, the Sloan Digital Sky Survey saw first light on its giant mosaic camera in 1998 and entered routine operations in 2000. While the collaboration and scope of the SDSS have changed over the years, many of its key principles have stayed fixed: the use of highly efficient instruments and software to enable surveys of unprecedented scientific reach, a commitment to creating high quality public datasets, and investigations that draw on the full range of expertise in a large international collaboration. The generous support of the Alfred P. Sloan Foundation has been crucial in all phases of the SDSS, alongside support from the participating institutions and national funding agencies in the U.S. and other countries.

The latest generation of the SDSS (SDSS-IV, 2014-2020) is extending precision cosmological measurements to a critical early phase of cosmic history (eBOSS), expanding its revolutionary infrared spectroscopic survey of the Galaxy in the northern and southern hemispheres (APOGEE-2), and for the first time using the Sloan spectrographs to make spatially resolved maps of individual galaxies (MaNGA). Two smaller surveys will be executed as subprograms of eBOSS: the Time Domain Spectroscopic Survey (TDSS) will be the first large-scale, systematic spectroscopic survey of variable sources; while the SPectroscopic IDentification of eROSITA Sources (SPIDERS) will provide an unique census of supermassive black-hole and large scale structure growth, targeting X-ray sources from ROSAT, XMM and eROSITA. Finally, the MaNGA stellar library (MaStar) will provide an optical stellar library covering a wide range of stellar parameters.

SDSS-III (2008-2014) undertook a major upgrade of the venerable SDSS spectrographs and added two powerful new instruments to execute an interweaved set of four surveys, mapping the clustering of galaxies and intergalactic gas in the distant universe (BOSS), the dynamics and chemical evolution of the Milky Way (SEGUE-2 and APOGEE), and the population of extra-solar giant planets (MARVELS). You can still visit the old SDSS3 Website, but it is no longer updated.

In its first five years of operations, the SDSS carried out deep multi-color imaging over 8000 square degrees and measured spectra of more than 700,000 celestial objects. With an ever-growing collaboration, SDSS-II (2005-2008) completed the original survey goals of imaging half the northern sky and mapping the 3-dimensional clustering of one million galaxies and 100,000 quasars. SDSS-II carried out two additional surveys: the Supernova Survey, which discovered and monitored hundreds of supernovae to measure the expansion history of the universe, and the Sloan Extension for Galactic Understanding and Exploration (SEGUE), which extended SDSS imaging towards the plane of the Galaxy and mapped the motions and composition of more than a quarter million Milky Way stars. The classic SDSS Website is still available, but it is no longer updated.