MMT Observatory

The MMT Observatory is an optical telescope featuring a 6.5-meter diameter primary mirror located at 2,616 meters elevation in the Santa Rita Mountains. Its structure incorporates a honeycomb design that reduces weight while allowing the retractable roof and walls to enable rapid thermal equilibration with the night sky.

The telescope began operations in 1979 as a multiple mirror design with six individual mirrors working together. The conversion to a single large mirror between 1998 and 2000 represented a major technological upgrade that improved the facility's capabilities.

The facility is jointly operated by the University of Arizona and Smithsonian Institution, attracting astronomers from multiple institutions who collaborate here. This partnership between academic and museum communities reflects how modern science brings different organizations together toward shared goals.

The facility sits on a mountain near Tucson and requires travel along mountain roads to reach. Visitors should prepare for higher elevation, cooler temperatures, and variable weather conditions depending on the season.

The primary mirror was specially engineered by the Steward Observatory Mirror Laboratory using a honeycomb internal structure that dramatically reduces mass. This innovative design enables better performance and faster response to temperature fluctuations compared to traditional solid mirrors.

Location: Arizona

Inception: 1979

Official opening: 1979

Elevation above the sea: 2,616 m

Diameter: 6.5 m

Part of: Fred Lawrence Whipple Observatory, Steward Observatory

Website: https://mmto.org

GPS coordinates: 31.68830,-110.88500

Latest update: December 8, 2025 19:57