Mauna Kea - Summit Observatories

Summit Observatories

Mauna Kea's summit is one of the best sites in the world for astronomical observation because a number of factors create favorable observing conditions. The atmosphere above the volcano is extremely dry, which is important for submillimeter and infrared astronomy because water vapor absorbs radiation in most of this region of the electromagnetic spectrum. The summit is above the inversion layer that separates lower maritime air from upper atmospheric air, keeping most cloud cover below the summit and ensuring the air on the summit is dry, and free of atmospheric pollution. The summit atmosphere is exceptionally stable; this lack of turbulence creates some of the world's best astronomical seeing. The very dark skies resulting from Mauna Kea's distance from city lights are preserved by legislation that minimizes light pollution from the surrounding area; the darkness level allows the observation of faint astronomical objects. These factors historically made Mauna Kea an excellent spot for stargazing.

In the 1950s, solar observatories were built on Haleakalā on Maui, as Mauna Kea was inaccessible by road above 12,000 ft (3,700 m). In the early 1960s, the Hawaii Island Chamber of Commerce began encouraging astronomical development of Mauna Kea, as an economic stimulus; this coincided with University of Arizona astronomer Gerard Kuiper's search for sites at which to use the newly improved detectors of infrared light, spurred by the rapid development of infrared astronomy. Site testing by Kuiper's assistant Alika Herring in 1964 confirmed the summit's outstanding suitability. An intense three-way competition for NASA funds to construct a large telescope began between Kuiper, Harvard University, and the University of Hawaii (UH), which only had experience in solar astronomy. This culminated in funds being awarded to the "upstart" UH proposal. UH rebuilt its small astronomy department into a new Institute for Astronomy, and in 1968 the Hawaii Department of Land and Natural Resources gave it a 65-year lease for all land within a 4 km (2.5 mi) radius of its telescope, essentially that above 11,500 ft (3,505 m). On its completion in 1970, the UH 88 in (2.2 m) was the seventh largest optical/infrared telescope in the world.

Other groups began requesting subleases on the newly accessible mountaintop. By 1970, two 24 in (0.6 m) telescopes had been constructed by the US Air Force and Lowell Observatory. In 1973, Canada and France agreed to build the 3.6 m CFHT on Mauna Kea. However, local organisations started to raise concerns about the environmental impact of the observatory. This led the Department of Land and Natural Resources to prepare an initial management plan, drafted in 1977 and supplemented in 1980. In January 1982, the UH Board of Regents approved a plan to support the continued development of scientific facilities at the site. In 1998, 2,033 acres (823 ha) were transferred from the observatory lease to supplement the Mauna Kea Ice Age Reserve. The 1982 plan was replaced in 2000 by an extension designed to serve until 2020: it instituted an Office of Mauna Kea Management, designated 525 acres (212 ha) for astronomy, and shifted the remaining 10,763 acres (4,356 ha) to "natural and cultural preservation". This plan was further revised to address concern expressed in the Hawaiian community that a lack of respect was being shown toward the cultural values of the mountain.

Today the Mauna Kea Science Reserve has 13 observation facilities, each funded by as many as 11 countries. It is one of the world's premier observatories for optical, infrared, and submillimeter astronomy, and in 2009 was the largest measured by light gathering power. There are nine telescopes working in the visible and infrared spectrum, three in the submillimeter spectrum, and one in the radio spectrum, with mirrors or dishes ranging from 0.9 m (3.0 ft) to 25 m (82 ft). In comparison, the Hubble Space Telescope has a 2.4 m (7.9 ft) mirror, similar in size to the UH88, now the second smallest telescope on the mountain. Planned new telescopes, including Pan-STARRS and the enormous Thirty Meter Telescope, have attracted controversy due to their potential cultural and ecological impact. If built, they are expected to replace older facilities on the summit rather than breaking new ground; the multi-telescope "outrigger" extension to the Keck telescopes, which required new sites, was denied its construction permit in 2006.