Mauna Kea Observatory

Mauna Kea Observatory, astronomical research facility, located on Hawaii's dormant volcano Mauna Kea, at an altitude of 4,205 m (13,796 ft). Mauna Kea offers nighttime viewing with minimal interference from human light sources. The observatory, founded in 1967, is affiliated with the University of Hawaii but has a number of internationally sponsored instruments. See also Observatory; Astronomy.

The observatory complex contains all of the necessities for astronomers who spend time at the observatory. Mauna Kea has dormitories and cafeterias at an altitude of about 3,000 m (about 9,000 ft), below the summit area of the observatory where the telescopes are located. Mauna Kea Observatory is so high that astronomers usually spend at least a day at the lower area before visiting the summit to allow their bodies to acclimate to the altitude.

Mauna Kea Observatory is home to 20 telescopes, sponsored by many nations. Seven of Mauna Kea’s telescopes are optical telescopes, meaning that they gather light that is visible to humans. The two largest optical telescopes on Mauna Kea are the twin United States Keck telescopes, both of which have 1,000-cm (394-in) primary mirrors. The huge mirrors are actually made up of many small segments whose movements are coordinated electronically. The Keck telescopes are the largest optical telescopes in the world and are run by the California Institute of Technology (Caltech), the University of California, and the National Aeronautics and Space Administration (NASA). The next largest telescope on Mauna Kea is the Japanese Subaru optical telescope, completed in 1998. The Subaru telescope has a primary mirror 830 cm (327 in) in diameter.

The Gemini North telescope, an international telescope almost as large as the Subaru telescope, began scientific work on Mauna Kea in 2000. The Gemini North telescope has a 810-cm (320-in) primary mirror. It has a sister telescope, Gemini South, near La Serena, Chile. Both telescopes are run by a consortium of scientists and institutions from the United States, the United Kingdom, Canada, Chile, Australia, Argentina, and Brazil. Three more optical telescopes are located on Mauna Kea. The Canada France Hawaii Telescope (CFHT) has a 360-cm (140-in) primary mirror. The University of Hawaii operates two optical telescopes on Mauna Kea. One has a mirror 220 cm (87 in) in diameter, and the other has a 61-cm (24-in) primary mirror.

Mauna Kea is also home to telescopes that gather light that humans cannot see. Mauna Kea holds two infrared telescopes, ten submillimeter telescopes, and one radio telescope. All three types of telescopes are designed for radiation with wavelengths longer than those of visible light. Infrared radiation has slightly longer wavelengths than visible light has. Submillimeter radiation encompasses the far end of the infrared band and the beginning of the microwave band of radiation. Radio waves have the longest wavelength of all radiation. See also Infrared Astronomy; Radio Astronomy.

The two infrared telescopes are the United Kingdom Infrared Telescope (UKIRT) and the U.S. Infrared Telescope Facility (IRTF). UKIRT has a primary mirror 380 cm (150 in) in diameter and IRTF has a 300-cm (120-in) primary mirror. The submillimeter telescopes on Mauna Kea are the British and Dutch James Clerk Maxwell Telescope (JCMT), the U.S. California Submillimeter Observatory (CSO) operated by the California Institute of Technology, and eight identical telescopes of the Submillimeter Array, a joint project of the United States and Taiwan. Submillimeter and radio telescopes are giant dish-shaped antennas and are measured in terms of the diameter of their dishes. The JCMT and CSO telescopes have 1,040-cm (410-in) dishes, and each of the eight telescopes in the Submillimeter Array has a 500-cm (200-in) dish. Construction began on the Submillimeter Array in 1997 and was scheduled to last for several years. Mauna Kea’s radio telescope is a member of the Very Long Baseline Array (VLBA), a network of radio telescopes that spans the United States. The VLBA telescope on Mauna Kea has a dish diameter of 2,500 cm (980 in).