Steward Observatory is the research arm of the Department of Astronomy at the University of Arizona.

It operates, or is a partner in telescopes at five mountain-top locations in Arizona, one in New Mexico, one in Hawaii, and one in Chile. It has provided instruments for three different space telescopes and numerous terrestrial ones. Steward has one of the few facilities in the world that can cast and figure the very large primary mirrors used in telescopes built in the early 21st century.

The Kitt Peak National Observatory (KPNO) is a United States astronomical observatory located on Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert. With more than twenty optical and two radio telescopes, it is one of the largest gatherings of astronomical instruments in the Earth's northern hemisphere.