Astrophysics (index)

Sloan Digital Sky Survey

(imaging survey of 500,000,000 objects in 35% of sky)

The Sloan Digital Sky Survey (SDSS) is a series of surveys (or a survey with multiple "phases") carried out with the Sloan 2.5m Telescope at Apache Point Observatory (APO), New Mexico, which was built for the purpose. It is named for Alfred P. Sloan Foundation.

Surveying began in 2000, covering 35% of sky, with Photometry of 500 million objects and spectra of 1 million objects. The median Redshift (z) of the galaxies is redshift z = .1, reaching as far as z = .7, with Quasars (QSO) to redshift z = 6 and beyond.

The original survey (SDSS-I) was Visible Light images using a Photometric System of five bands:

IDcentered on

SDSS phases:

  • SDSS-I (2000-2005, Data Releases 1-5)
  • SDSS-II (2005-2008, Data Releases 6-7)
  • SDSS-III (2008-2014, Baryon Oscillation Spectroscopic Survey (BOSS), SEGUE-2, APOGEE, MARVELS, TDSS, Data Releases 8-10)
  • SDSS-IV (2014-?, APOGEE-2, eBOSS, MaNGA)

Among the sub-surveys:

  • APOGEE (APO Galactic Evolution Experiment) - Infrared (IR) survey of the Milky Way interior.
  • BOSS (Baryon Oscillation Spectroscopic Survey) - survey to map the spatial resolution of luminous red galaxies (LRG) and quasars.
  • MARVELS (Multi-object APO Radial Velocity Exoplanet Large-area Survey) - survey to find Extra Solar Planets using Radial Velocity measurements.
  • SEGUE and SEGUE-2 (Sloan Extension for Galactic Understanding and Exploration) - follow-up surveys to SDSS of a group of 119,000 Milky Way stars.
  • TDSS (Time Domain Spectroscopic Survey) - spectroscopic investigation of variable sources.

SDSSSDSS 1346-0031Sloan Digital Sky Survey 
SegueSegue 2Sloan Digital Sky SurveySEGUE discovery

Referenced by:
Atacama Cosmology Telescope (ACT)
Astronomical Survey
Baryon Acoustic Oscillations (BAO)
Baryon Oscillation Spectroscopic Survey (BOSS)
Conditional Stellar Mass Function (CSMF)
Galaxy Zoo
GALEX Arecibo SDSS Survey (GASS)
Gas Fraction Estimation
G Band
Galaxy Zoo 2 (GZ2)
J Designator
Luminous Red Galaxy (LRG)
Photometric System
Ritchey-Chrétien Telescope (RCT)
Sloan Great Wall (SGW)
Sloan 2.5m Telescope
SkyMapper Southern Survey (SMSS)
TiNy Titans (TNT)
Ultra-Faint Dwarf Galaxy (UFD)