In astronomy, a redshift survey is a survey of a section of the sky to measure the redshift of astronomical objects. Using Hubble's law, the redshift can be used to calculate the distance of an object from Earth. By combining redshift with angular position data, a redshift survey maps the 3D distribution of matter within a field of the sky. These observations are used to measure properties of the large scale structure of the universe. The Great Wall, a vast conglomeration of galaxies over 500 million light-years wide, provides a dramatic example of a large-scale structure that redshift surveys can detect. In ancient Greece and other early civilizations, astronomy consisted largely of astrometry, measuring positions of stars and planets in the sky. ... Redshift describes a change in the wavelength of light, in which the wavelength is longer, or redder, than when it was emitted at the source. ... Hubbles law is the statement in physical cosmology that the redshift in light coming from distant galaxies is proportional to their distance. ... Astronomy and cosmology examine the universe to understand the large-scale structure of the cosmos. ... The Great Wall is the largest known super-structure in the Universe. ...

The most notable, recent and low-redshift surveys are the 2dF Galaxy Redshift Survey and the Sloan Digital Sky Survey. At high redshift there exists the DEEP2 Redshift Survey. In astronomy, the 2dF Galaxy Redshift Survey (Two-degree-Field Galaxy Redshift Gurvey), or 2dFGRS is a redshift survey conducted by the Anglo-Australian Observatory in the 1990s. ... The Sloan Digital Sky Survey or SDSS is a major redshift survey using a dedicated 2. ... The DEEP2 Survey or DEEP2 is a Redshift survey of the Redshift~1 universe. ...