MMT Observatory MMT Observatory The MMT Observatory (MMTO) is an astronomical observatory on the site of Fred Lawrence Whipple Observatory (IAU observatory code 696). The Whipple observatory complex is located on Mount Hopkins, Arizona, US (55 km south of Tucson) in the Santa Rita Mountains. The observatory is run by the University of Arizona and the Smithsonian Institution, and has a visitor center in nearby Amado, Arizona. The MMTO is the home of the MMT (formerly Multiple Mirror Telescope), which currently has a primary mirror 6.5 m in diameter. The name originally comes from the fact that the light gathering for the
Goldendale Observatory State Park and north dome a diameter of 10 feet (3 m). The observatory served as the National Astronomical League's official headquarters during a solar eclipse which occurred on February 26, 1979, six years after the observatory opened. Approximately 15,000 people came to the town of Goldendale on that date to observe the eclipse. The Observatory and its lands were acquired by the state of Washington in 1980, after being operated by the Goldendale Observatory Corporation since its dedication on October 13, 1973. The park received its new designation as a "state park heritage site" in 2014. In July 2017, all structures