The Keck Observatory sits atop Mauna Kea on the Big Island of Hawaii. Credit: NASA/JPL
The twin telescopes at the W.M. Keck Observatory are the largest optical and infrared telescopes in the world, according to the observatory's website. Because of the size and location of the telescopes, they are in high demand among professional astronomers. (The observatory is not open to the public.) Keck has participated in several notable discoveries.
The observatory is located atop Mauna Kea, a dormant volcano in Hawaii. Because it is so near the equator, Mauna Kea makes an excellent astronomical observation site.
"In the middle of the Pacific Ocean, Hawaii Island is surrounded by thousands of miles of thermally stable seas," the Keck Observatory wrote on its website. "The 13,796-foot Mauna Kea summit has no nearby mountain ranges to roil the upper atmosphere. Few city lights pollute Hawaiian night skies, and for most of the year, the atmosphere above Mauna Kea is clear, calm and dry."
Both telescopes, named Keck I and Keck II, measure 10 meters (32.8 feet) across. The mirrors for each telescope are made of 36 lightweight segments that work together similarly to a single mirror. The telescopes are housed in insulated domes of 700,000 cubic feet. Giant air conditioners run all day to keep the temperature at or below freezing. This helps reduce deformation of the telescopes' steel and mirrors, according to the Keck website. The primary mirror assembly of the 10-meter Keck II telescope is made of 36 parts that can adapt to atmospheric conditions.