Multiple Mirror Telescope (MMT)
A 6.5-meter telescope located at an altitude of 2,606 m (8,550 ft) on the
summit of Mount Hopkins, the second highest peak in the Santa Rita Range
of the Coronado National Forest, about 55 km south of Tucson, Arizona, on
the grounds of the Smithsonian's Fred Lawrence
Whipple Observatory. In 1998, the large single mirror replaced six identical
1.8-m mirrors on a common mount (with a combined light-collecting power
of a 4.5-meter mirror), which had been in use since 1979. Just before it
was upgraded, the old MMT was used in a pioneering demonstration of nulling
interferometry to image the dust cloud around Betelgeuse.
The MMT is a joint venture of the University of Arizona, which operates
the MMT, and the Smithsonian Institution.