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
Lowell Observatory Flagstaff. Also located on the Mars Hill campus is the Pluto Discovery Telescope, used by Clyde Tombaugh in 1930 to discover the dwarf planet Pluto. Lowell Observatory currently operates four research telescopes at its Anderson Mesa dark-sky site, located southeast of Flagstaff, including the Perkins Telescope (in partnership with Boston University) and the John S. Hall Telescope. Lowell is a partner with the United States Naval Observatory and Naval Research Laboratory in the Navy Precision Optical Interferometer (NPOI) also located at that site. The Observatory also operates smaller research telescopes at its historic site on Mars Hill and in Australia