mountain profile Institute for Astronomy University of Hawaii

About Mauna Kea Observatories

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Hawaii is Earth's connecting point to the rest of the Universe.  The summit of Mauna Kea on the Island of Hawaii hosts the world's largest astronomical observatory, with telescopes operated by astronomers from eleven countries. The combined light-gathering power of the telescopes on Mauna Kea is fifteen times greater than that of the Palomar telescope in California -- for many years the world's largest -- and sixty times greater than that of the Hubble Space Telescope.

The observatories

There are currently thirteen working telescopes near the summit of Mauna Kea. Nine of them are for optical and infrared astronomy, three of them are for submillimeter wavelength astronomy and one is for radio astronomy. They include the largest optical/infrared  telescopes in the world (the Keck telescopes), the largest dedicated infrared telescope (UKIRT) and the largest submillimeter telescope in the world (the JCMT). The westernmost antenna of the Very Long Baseline Array (VLBA) is situated at a lower altitude two miles from the summit. 

The geography of Mauna Kea

Mauna Kea ("White Mountain") is a dormant volcano on the island of Hawaii, the largest and southernmost of the Hawaiian Islands.  It is located about 300 km (190 miles) from Honolulu, which lies on the island of Oahu. The highest point in the Pacific Basin, and the highest island-mountain in the world, Mauna Kea rises 9,750 meters (32,000 ft) from the ocean floor to an altitude of 4,205 meters (13,796 ft) above sea level, which places its summit above 40 percent of the Earth's atmosphere. The broad volcanic landscape of the summit area is made up of cinder cones on a lava plateau. The lower slopes of Mauna Kea are popular for hunting, hiking, sightseeing, and bird watching in an environment that is less hostile than the barren summit area.

Why Mauna Kea is a unique site for astronomy

Mauna Kea is unique as an astronomical observing site. The atmosphere above the mountain is extremely dry -- which is important in measuring infrared and submillimeter radiation from celestial sources - and cloud-free, so that the proportion of clear nights is among the highest in the world. The exceptional stability of the atmosphere above Mauna Kea permits more detailed studies than are possible elsewhere, while its distance from city lights and a strong island-wide lighting ordinance ensure an extremely dark sky, allowing observation of the faintest galaxies that lie at the very edge of the observable Universe. A tropical inversion cloud layer about 600 meters (2,000 ft) thick, well below the summit, isolates the upper atmosphere from the lower moist maritime air and ensures that the summit skies are pure, dry, and free from atmospheric pollutants.

The stewardship of Mauna Kea

Starting in the 1960s, the UH Institute for Astronomy provided the scientific impetus for the development of Mauna Kea into the world's premier site for ground-based astronomical observatories. More major telescopes are now located on Mauna Kea than on any other single mountain peak, and Mauna Kea is widely recognized as offering better conditions for optical, infrared and millimeter/submillimeter measurements than any other developed site. 

The University of Hawaii has a lease from the State of Hawaii for all land within a 2.5-mile radius of the site of the UH 2.2-m Telescope - essentially all of the land above 3,700 meters (12,000 ft) elevation - except for the portions of this circular area which lie within the Mauna Kea Ice Age Natural Area Reserve. The leased land is known as the Mauna Kea Science Reserve.  The adoption of the Mauna Kea Science Reserve Master Plan by the University of Hawai'i Board of Regents in June 2000 marked a critical milestone in the management of Mauna Kea. Meetings and public hearings spanning a period of nearly two years went into the formulation of the Master Plan, which establishes management guidelines for the next 20 years. The process reflected the community's deeply rooted concerns over the use of Mauna Kea, including respect for Hawaiian cultural beliefs, protection of environmentally sensitive habitat, recreational use of the mountain, as well as astronomy research.  Management of the summit area is now the responsibility of the Office of Mauna Kea Management in Hilo. 

Onizuka Center for International Astronomy

Astronomers and technicians must acclimatize when coming from sea level to work at the summit. For this reason, "mid-level" facilities are provided at an altitude of 2,800 meters (9,300 ft). These facilities were constructed in 1982 and have been named in honor of Ellison Onizuka, an astronaut from the Big Island who died in the 1986 Challenger disaster. 

The Onizuka Center also includes a  Visitor Information Station which is open to the public. It contains exhibits about the mountain and its observatories, offers evening sky-viewing opportunities, and provides guided tours of the summit.

Visiting Mauna Kea Observatories