Kitt Peak National Observatory

Observatory in the Quinlan Mountains near Tucson, Arizona, operated by AURA (the Association of Universities for Research into Astronomy), by agreement with the National Science Foundation of the United States. It is a division of the National Optical Astronomy Observatories. Its main telescopes are the 4-m/158-in Mayall reflector (1973) and the McMath Solar Telescope (1962), the world's largest of its type.

Among numerous other telescopes on the site is a 2.3-m/90-in reflector owned by the Steward Observatory of the University of Arizona, and a 3.5-m/138-in reflecting telescope, opened in 1994, owned by the WIYN consortium, which comprises the University of Wisconsin, Indiana University, Yale University, and the National Optical Astronomy Observatories.