Richard B. Dunn Solar Telescope

Dunn Solar Telescope
Alternative namesVacuum Tower Telescope at Sacramento Peak, Richard B. Dunn Solar Telescope
Location(s)New Mexico
Coordinates32°47′14″N 105°49′14″W / 32.78728°N 105.8205°W / 32.78728; -105.8205
Wavelength310 nm (970 THz)–1,000 nm (300 THz)
Diameter76 cm (2 ft 6 in)
Collecting area0.456 m2 (4.91 sq ft)
Focal length54.86 m (180 ft 0 in)
Websitesunspot.solar
Location of Richard B. Dunn Solar Telescope
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The Dunn Solar Telescope, also known as the Richard B. Dunn Solar Telescope, was a unique vertical-axis solar telescope that specializes in high-resolution imaging and spectroscopy. It is located at Sacramento Peak in Sunspot, New Mexico. It was the main telescope at the Sunspot Solar Observatory, operated by New Mexico State University in partnership with the National Solar Observatory through funding from the National Science Foundation, the state of New Mexico, and private funds from other partners. The Dunn Solar Telescope helps astrophysicists worldwide better understand the Sun and how it affects Earth. In February 2026, the U.S. National Science Foundation announced that the telescope would be dismantled and the Sacramento Peak site restored following the discovery of liquid mercury in the facility and subsequent safety and environmental concerns.

Completed in 1969, the telescope was upgraded with high-order adaptive optics in 2004 and was a highly versatile astrophysical observatory that served as an important test platform for developing new instrumentation and technologies.