Mauna Kea Observatories
Big Island

Latitude: 19-49’25” N Longitude: 155-28’15” W Altitude 13,803 ft
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 telescopes on Maunakea are operated by 12 separate nonprofit observatories
Together, the Observatories make Maunakea the most scientifically productive site for astronomy world-wide.
Visiting Maunakea
The Visitor Information Station (VIS) is open 7 days a week from 8am to 300 pm, with Interpretive Guides and Maunakea Rangers to answer questions. Luas are available twenty-four hours daily. During the day, a solar telescope is available for viewing the sun.
F.A.Q.
Frequently Asked Questions
Is Maunakea a volcano?
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.
Who owns or manages the land at the summit the telescopes are built on?
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.
Aerial Tour of the Mauna Kea Observatories
Obtained in February 1998.
Copyright 1998, Richard Wainscoat, All Rights Reserved
All telescopes except the VLBA
All telescopes except the VLBA antenna can be seen in this photograph. The three main loci of development can be seen – at the lower right are the submillimeter telescopes in submillimeter valley. In the center left are the Subaru telescope, the Keck telescopes and the IRTF. Behind, on the summit ridge, are the CFHT, Gemini north telescope, UH 2.2-meter telescope, UKIRT, and UH 0.6-meter telescope.
Caltech Submillimeter Observatory
At the left is the Caltech Submillimeter Observatory. The large cylindrical structure at the right is the James Clerk Maxwell Telescope. The building in the foreground on the right is the antenna assembly buidling for the submillimeter array. The array is not visible in this photograph; it extends to the lower right.
Telescopes
From left to right, the telescope structures are JCMT, Submillimeter array assembly building, CSO, Subaru, UH 0.6-meter, Keck 1, Keck 2, UKIRT, IRTF, UKIRT, UH 2.2-meter, Gemini, and CFHT. The true summit of Mauna Kea is located immediately in front of the UH 2.2-meter telescope dome in this photograph. In the distance is Haleakala on the island of Maui.
Telescopes
From left to right, the telescope domes are JCMT, Subaru, CSO, Keck 1, Keck 2, IRTF, UH 0.6-meter, UKIRT, CFHT, UH 2.2-meter, and Gemini. The submillimeter array will extend behind the JCMT.
The Subaru Telescope
The Subaru Telescope is being constructed by the National Astronomical Observatory of Japan. First light is planned for 1998, and it is expected to be fully operational in 2000. The building in the foreground is the support building, where telescope operators and astronomers will be located. This design was chosen to minimize sources of heat inside the telescope structure, in order to maximize telescope image quality (heat degrades image quality).
VLBA antenna
This antenna is one of a large network of radio antennas that comprise the Very Long Baseline Array. The Hawaii antenna is the westernmost antenna; the easternmost antenna is in the U.S. Virgin Islands.
Kecks and Subaru Telescopes
In the center are the open domes of the W.M. Keck Observatory. To the right is the Subaru Telescope. Some of the antenna pads for the submillimeter array can be seen to the right of the Subaru Telescope. These concrete pads have been painted brown to help reduce their impact. In the distance, at the left is the almost perfectly formed cinder cone Pu’u Hau Kea, and to its right is Lake Waiau, at an altitude of 13,020 feet. It has an area of about 40 acres.
Keck Telescopes
The mirrors of the Keck telescopes can be seen inside the open domes. The mirrors are relecting light from the sky, so appear blue. Both telescopes are pointing towards the north – a direction chosen to avoid getting sunlight on the telescope. Close-up photographs of the Keck telescopes may be found later in this series.
Telescopes
All of the optical/IR telescopes can be seen in this photograph. In the distance at the right is the Hawaii antenna of the Very Long Baseline Array, located about 2 miles from the summit. The submillimeter telescopes cannot be seen in this photograph.
The Gemini and UH 2.2-meter telescope
The Gemini telescope, on the right, is presently being built. Adjacent and to the left of the Gemini telescope is the UH 2.2-meter telescope. The extension at the top of the dome of this telescope houses a crane. This crane is used to bring the aluminizing tank to the telescope when the primary mirror is aluminized. (In most other telescopes, the mirror is transported to the aluminizing tank.) In the distance is the dormant volcano Hualalai.
Ridge near the summit
The ridge near the summit, only about 10 feet lower than the summit, was the first area on which telescopes were built on Mauna Kea. The UH 2.2-meter telescope (center) was the first large telescope on Mauna Kea. The Gemini northern 8-meter telescope is the largest and newest telescope in this area (open silver dome).
Telescopes
In the center are the open domes of the W.M. Keck Observatory. These are the largest optical/IR telescopes in the world. Each telescope has a mirror 10 meters in diameter. Each telescope mirror is made up of 36 separate precisely controlled segments, joined together in a honeycomb pattern. At the left of the photograph is the NASA IRTF. To the right of the Keck telescopes is the Subaru telescope (scheduled to become operational in 1999). In the valley below are the submillimeter telescopes – CSO (left), JCMT (center, open), and the submillimeter array. The roads leading to antenna sites for the submillimeter array (also scheduled to become operational in 1999) can be seen on the right. No array antennas had been installed on Mauna Kea when these photographs were taken.
Telescopes
In the foreground on the summit ridge, from left to right, are the UH 0.6-meter telescope (small white dome), the United Kingdom Infrared Telescope, the UH 2.2-meter telescope, the Gemini Northern 8-meter telescope (silver, open) and the Canada-France-Hawaii Telescope. On the right are the NASA Infrared Telescope Facility (silver), the twin domes of the W.M. Keck Observatory; behind and to the left of them is the Subaru Telescope. In the valley below are the Caltech Submillimeter Observatory (silver), the James Clerk Maxwell Telescope (white, open), and the assembly building for the submillimeter array.
Above the summit access road
From high above the summit access road, but about 500 feet lower than the summit (at approximately the altitude of the submillimeter telescopes), not all of the telescopes can be seen. The top of the Gemini dome can be seen directly above the summit. This photo shows how steep the access road is. The Keck telescopes and IRTF are hidden behind the summit ridge.
Telescopes
From an altitude of about 13,800 feet (level with the summit, seen on the left of this photo), the Keck telescopes are hidden by the summit ridge. The Gemini northern 8-meter telescope dome is the largest structure from this perspective. In the distance is Haleakala, on the island of Maui.
Keck and Subaru telescopes
The twin domes of the Keck telescopes are on the left. The Subaru telescope structure is behind them and to their right. Behind the telescopes is Pu`u Poliahu.
Richard Wainscoat in a Hughes 500
These photographs were taken by Richard Wainscoat in a Hughes 500 helicopter. The rear door of the helicopter was removed. The photographs were taken using a Mamiya 645 Pro camera mounted on a gyroscopic stabilizer, and with a Nikon N90S camera with telephoto zoom lens. Special thanks are due to the pilot, Marty Williams, for his excellent flying. This photo was taken by Andy Perala of the W.M. Keck Observatory, who provided a great deal of help in organizing this photo shoot..
Hale Pohaku
Because of the extreme altitude of Mauna Kea, astronomers and technicians must acclimatize and live at an intermediate altitude. The Onizuka Center for International Astronomy (also known as Hale Pohaku – Hawaiian for “Stone House”) has living facilities for up to 72 people working at the summit, as well as a visitor center and other support buildings. This photograph is partially obscured by drifting smoke from a distant fire – the 1998 winter was very dry, with drought conditions and extreme fire danger on the Island of Hawaii.
The NASA Infrared Telescope
The NASA Infrared Telescope Facility consists of a 3-meter infrared optimized telescope. It is operated by the University of Hawaii, Institute for Astronomy, for NASA.
Keck Telescope
The Keck 2 telescope of the W.M. Keck Observatory was the second 10-meter telescope to be built on Mauna Kea. It came into operation in 1996. Its 10-meter primary mirror comprises 36 separate hexagonally shaped segments. The primary mirror can be seen in this photograph, and its outer edge shows the hexagonal segments.
W.M. Keck Observatory
The primary mirrors of the two telescopes of the W.M. Keck Observatory can be seen in this photograph. At the left is the Keck 2 telescope, and at the right is the Keck 1 telescope. Behind the domes, a carport is being constructed to protect workers and visitors from falling ice.
CFHT
The Canada-France-Hawaii Telescope lies at the northern end of the summit ridge, and was one of three telescopes that came into operation on Mauna Kea in 1980 (the others were UKIRT and IRTF).