Cambridge Optical Aperture Synthesis Telescope
Encyclopedia
COAST, the Cambridge Optical Aperture Synthesis Telescope, is a multi-element optical astronomical interferometer
with baselines of up to 100 metres, which uses aperture synthesis
to observe stars with angular resolution
as high as one thousandth of one arcsecond (producing images with much higher resolution than can be obtained using individual telescopes such as the Hubble Space Telescope
). The principal limitation is that COAST can only image bright star
s. COAST was the first long-baseline interferometer to obtain high-resolution images of the surfaces of stars other than our sun (although the surfaces of other stars had previously been imaged at lower resolution using Aperture Masking Interferometry
on the William Herschel Telescope
).
The COAST array was conceived by John E. Baldwin
, and is operated by the Cavendish Astrophysics Group
. It is situated at the Mullard Radio Astronomy Observatory
in Cambridgeshire
, England
.
Astronomical interferometer
An astronomical interferometer is an array of telescopes or mirror segments acting together to probe structures with higher resolution by means of interferometry....
with baselines of up to 100 metres, which uses aperture synthesis
Aperture synthesis
Aperture synthesis or synthesis imaging is a type of interferometry that mixes signals from a collection of telescopes to produce images having the same angular resolution as an instrument the size of the entire collection...
to observe stars with angular resolution
Angular resolution
Angular resolution, or spatial resolution, describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object...
as high as one thousandth of one arcsecond (producing images with much higher resolution than can be obtained using individual telescopes such as the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
). The principal limitation is that COAST can only image bright star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s. COAST was the first long-baseline interferometer to obtain high-resolution images of the surfaces of stars other than our sun (although the surfaces of other stars had previously been imaged at lower resolution using Aperture Masking Interferometry
Aperture masking interferometry
Aperture Masking Interferometry is a form of speckle interferometry, allowing diffraction limited imaging from ground-based telescopes. This technique allows ground based telescopes to reach the maximum possible resolution, allowing ground-based telescopes with large diameters to produce far...
on the William Herschel Telescope
William Herschel Telescope
The William Herschel Telescope is a optical/near-infrared reflecting telescope located at the Observatorio del Roque de los Muchachos on the island of La Palma in the Canary Islands, Spain. The telescope, which is named after William Herschel, is part of the Isaac Newton Group of Telescopes...
).
The COAST array was conceived by John E. Baldwin
John E. Baldwin
John Evan Baldwin FRS has worked at the Cavendish Astrophysics Group since 1954. He played a pivotal role in the development of interferometry in Radio Astronomy, and later astronomical optical interferometry and lucky imaging...
, and is operated by the Cavendish Astrophysics Group
Cavendish Astrophysics Group
The Cavendish Astrophysics Group is based at the Cavendish Laboratory at the University of Cambridge. The group operates all of the telescopes at the Mullard Radio Astronomy Observatory except for the 32m MERLIN telescope, which is operated by Jodrell Bank.The group is the second largest of three...
. It is situated at the Mullard Radio Astronomy Observatory
Mullard Radio Astronomy Observatory
Mullard Radio Astronomy Observatory is home to a number of large aperture synthesis radio telescopes, including the One-Mile Telescope, 5-km Ryle Telescope, and the Arcminute Microkelvin Imager...
in Cambridgeshire
Cambridgeshire
Cambridgeshire is a county in England, bordering Lincolnshire to the north, Norfolk to the northeast, Suffolk to the east, Essex and Hertfordshire to the south, and Bedfordshire and Northamptonshire to the west...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
.
External links
- COAST
- Some of the first high-resolution optical images of the surfaces of distant stars obtained using COAST and the William Herschel TelescopeWilliam Herschel TelescopeThe William Herschel Telescope is a optical/near-infrared reflecting telescope located at the Observatorio del Roque de los Muchachos on the island of La Palma in the Canary Islands, Spain. The telescope, which is named after William Herschel, is part of the Isaac Newton Group of Telescopes...
- Google maps image with COAST at the center