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Subaru (telescope)
Encyclopedia
Subaru Telescope is the 8.2 metre
flagship telescope of the National Astronomical Observatory of Japan
, located at the Mauna Kea Observatory
on Hawaii
. It is named after the open star cluster known in English as the Pleiades
. It had the largest monolithic primary mirror
in the world from its commissioning until 2005.
focus below the primary mirror, in enclosures on either of two Nasmyth
focal points on the sides of the telescope mount, to which light can be directed with a tertiary mirror, or, in an arrangement rare on large telescopes, at the prime focus, in lieu of a secondary mirror, to provide a wide field of view suited to deep wide-field surveys.
In 1984, the University of Tokyo
formed an engineering working group to study the concept of a 7.5-metre telescope. In 1985, the astronomy committee of Japan's science council gave top priority to the development of a "Japan National Large Telescope" (JNLT), and in 1986, the University of Tokyo signed an agreement with the University of Hawaii
to build the telescope in Hawaii. In 1988, the National Astronomical Observatory of Japan was formed through a reorganization of the University's Tokyo Astronomical Observatory, to oversee the JNLT and other large national astronomy projects.
Construction of the telescope began in April 1991, and later that year, a public contest gave the telescope its official name, "Subaru Telescope." Construction was completed in 1998, and the first scientific images were taken in January 1999. In September 1999, Princess Sayako of Japan dedicated the telescope.
A number of state-of-the-art technologies were worked into the telescope. For example, 261 computer-controlled actuators press the main mirror from the back to correct its distortion when the telescope changes its orientation. The telescope enclosure building is also shaped to minimize air turbulence, to improve the quality of astronomical images.
Subaru is one of the few state-of-the-art telescopes to have ever been used with the naked eye. For the dedication, an eyepiece was constructed so that Princess Sayako could look through it directly. It was enjoyed by the staff for a few nights until it was replaced with the much more sensitive working instruments.
Observation using Nasmyth foci resumed on July 22, and Cassegrain focus resumed on August 26.
Several cameras and spectrographs can be mounted at Subaru Telescope's four focal points for observations in visible and infrared wavelengths.
Multi-Object Infrared Camera and Spectrograph (MOIRCS) : Wide-field camera and spectrograph with the ability to take spectra of multiple objects simultaneously, mounts on the Cassegrain focus.
Infrared Camera and Spectrograph (IRCS) : Used in conjunction with the new 188-element adaptive optics unit (AO188), mounted at the infrared Nasmyth focus.
Cooled Mid Infrared Camera and Spectrometer (COMICS) : Mid-infrared camera and spectrometer with the ability to study cool interstellar dust, mounts on the Cassegrain focus.
Faint Object Camera And Spectrograph (FOCAS) : Visible-light camera and spectrograph with the ability to take spectra of up to 100 objects simultaneously, mounts on the Cassegrain focus.
Subaru Prime Focus Camera (Suprime-Cam) : 80-megapixel wide-field visible-light camera, mounts at the prime focus.
High Dispersion Spectrograph (HDS) : Visible-light spectrograph mounted at the optical Nasmyth focus.
Fiber Multi Object Spectrograph (FMOS) : Infrared spectrograph using movable fiber optics to take spectra of up to 400 objects simultaneously. Mounts at the prime focus.
High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO) : Infrared camera for hunting planets around other stars. Used with AO188, mounted at the infrared Nasmyth focus.
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
flagship telescope of the National Astronomical Observatory of Japan
National Astronomical Observatory of Japan
The is an astronomical research organisation comprising several facilities in Japan, as well as an observatory in Hawaii. It was established in 1988 as an amalgamation of three existing research organizations - the Tokyo Astronomical Observatory of the University of Tokyo, International Latitude...
, located at the Mauna Kea Observatory
Mauna Kea Observatory
The Observatories at Mauna Kea, , are an independent collection of astronomical research facilities located on the summit of Mauna Kea on the Big Island of Hawai'i, USA. The facilities are located in a special land use zone known as the "Astronomy Precinct," which is located in the Mauna Kea...
on Hawaii
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
. It is named after the open star cluster known in English as the Pleiades
Pleiades (star cluster)
In astronomy, the Pleiades, or Seven Sisters , is an open star cluster containing middle-aged hot B-type stars located in the constellation of Taurus. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky...
. It had the largest monolithic primary mirror
Primary mirror
A primary mirror is the principal light-gathering surface of a reflecting telescope.-Description:The primary mirror of a reflecting telescope is a spherical or parabolic shaped disks of polished reflective metal , or in later telescopes, glass or other material coated with a reflective layer...
in the world from its commissioning until 2005.
Overview
Subaru is a Ritchey-Chretien reflecting telescope. Instruments can be mounted at a CassegrainCassegrain reflector
The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas....
focus below the primary mirror, in enclosures on either of two Nasmyth
Nasmyth telescope
The Nasmyth telescope, also called Nasmyth-Cassegrain, is a reflecting telescope developed by James Nasmyth. It is a modified form of a Cassegrain telescope, mounted on an alt-azimuth mount.-Scheme:...
focal points on the sides of the telescope mount, to which light can be directed with a tertiary mirror, or, in an arrangement rare on large telescopes, at the prime focus, in lieu of a secondary mirror, to provide a wide field of view suited to deep wide-field surveys.
In 1984, the University of Tokyo
University of Tokyo
, abbreviated as , is a major research university located in Tokyo, Japan. The University has 10 faculties with a total of around 30,000 students, 2,100 of whom are foreign. Its five campuses are in Hongō, Komaba, Kashiwa, Shirokane and Nakano. It is considered to be the most prestigious university...
formed an engineering working group to study the concept of a 7.5-metre telescope. In 1985, the astronomy committee of Japan's science council gave top priority to the development of a "Japan National Large Telescope" (JNLT), and in 1986, the University of Tokyo signed an agreement with the University of Hawaii
University of Hawaii
The University of Hawaii System, formally the University of Hawaii and popularly known as UH, is a public, co-educational college and university system that confers associate, bachelor, master, and doctoral degrees through three university campuses, seven community college campuses, an employment...
to build the telescope in Hawaii. In 1988, the National Astronomical Observatory of Japan was formed through a reorganization of the University's Tokyo Astronomical Observatory, to oversee the JNLT and other large national astronomy projects.
Construction of the telescope began in April 1991, and later that year, a public contest gave the telescope its official name, "Subaru Telescope." Construction was completed in 1998, and the first scientific images were taken in January 1999. In September 1999, Princess Sayako of Japan dedicated the telescope.
A number of state-of-the-art technologies were worked into the telescope. For example, 261 computer-controlled actuators press the main mirror from the back to correct its distortion when the telescope changes its orientation. The telescope enclosure building is also shaped to minimize air turbulence, to improve the quality of astronomical images.
Subaru is one of the few state-of-the-art telescopes to have ever been used with the naked eye. For the dedication, an eyepiece was constructed so that Princess Sayako could look through it directly. It was enjoyed by the staff for a few nights until it was replaced with the much more sensitive working instruments.
Mishaps During Construction
Two separate incidents claimed the lives of four workers during the construction of the telescope. On October 13, 1993, 42-year-old Paul F. Lawrence was fatally injured when a forklift tipped over onto him. On January 16, 1996, sparks from a welder ignited insulation which smoldered, generating noxious smoke that killed Marvin Arruda, 52, Ricky Del Rosario, 38, and Warren K. "Kip" Kaleo, 36, and sent twenty-six other workers to the hospital in Hilo. All four workers are memorialized by a plaque outside the base of the telescope dome and a sign posted temporarily each January along the Mauna Kea access road.Mishap in 2011
On July 2, 2011, the telescope operator in Hilo noted an anomaly from the top unit of the telescope. Upon further examination, coolant from the top unit was found to have leaked over the primary mirror and other parts of the telescope.Observation using Nasmyth foci resumed on July 22, and Cassegrain focus resumed on August 26.
Instruments
Multi-Object Infrared Camera and Spectrograph (MOIRCS) : Wide-field camera and spectrograph with the ability to take spectra of multiple objects simultaneously, mounts on the Cassegrain focus.
Infrared Camera and Spectrograph (IRCS) : Used in conjunction with the new 188-element adaptive optics unit (AO188), mounted at the infrared Nasmyth focus.
Cooled Mid Infrared Camera and Spectrometer (COMICS) : Mid-infrared camera and spectrometer with the ability to study cool interstellar dust, mounts on the Cassegrain focus.
Faint Object Camera And Spectrograph (FOCAS) : Visible-light camera and spectrograph with the ability to take spectra of up to 100 objects simultaneously, mounts on the Cassegrain focus.
Subaru Prime Focus Camera (Suprime-Cam) : 80-megapixel wide-field visible-light camera, mounts at the prime focus.
High Dispersion Spectrograph (HDS) : Visible-light spectrograph mounted at the optical Nasmyth focus.
Fiber Multi Object Spectrograph (FMOS) : Infrared spectrograph using movable fiber optics to take spectra of up to 400 objects simultaneously. Mounts at the prime focus.
High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO) : Infrared camera for hunting planets around other stars. Used with AO188, mounted at the infrared Nasmyth focus.