The Kepler space telescope is a retired space telescope launched by NASA in March 2009 to discover Earth-size exoplanets in or near habitable zones and to estimate how many of the billions of stars in the Milky Way have such planets. 

Kepler's sole scientific instrument was a photometer that continually monitored the brightness of approximately 150,000 main sequence stars in a fixed field of view. During its service, Kepler observed 530,506 stars and detected 2,662 exoplanets.

Both in 2012 and 2013, one of the spacecraft's four reaction wheels used for pointing the spacecraft stopped turning, disabling the collection of science data. However, in November 2013, the Kepler K2 "Second Light" proposal was announced, utilizing the disabled Kepler in a way that could detect habitable planets around smaller, dimmer red dwarfs. 

On October 30, 2018, after the spacecraft ran out of fuel, NASA announced that the telescope would be retired. A newer NASA mission, TESS, launched in 2018, is continuing the search for exoplanets.

Peranso makes use of data obtained from the Multimission Archive at the Space Telescope Science Institute (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NAG5-7584 and by other grants and contracts.