James Clerk Maxwell Telescope

The James Clerk Maxwell Telescope (JCMT) is a 15-metre submillimetre-wavelength telescope at Mauna Kea Observatory in Hawaii. It is the largest astronomical telescope in the world designed specifically to operate in the submillimetre regime (between the far-infrared and the microwave regions of the electromagnetic spectrum). It is used to study our Solar System, interstellar dust and gas, and distant galaxies.

History

In the late 1960s the Astronomy Committee of the UK's Science Research Council (SRC, for forerunner of PPARC) considered the importance of astronomical observations at submillimetre and millimetre wavelengths. A series of proposals and debates led, in 1975, to the SRC millimetre steering committee concluding that it would be possible to construct a 15-metre diameter telescope capable of observing at wavelengths down to 750µm. The project, then called the National New Technology Telescope (NNTT), was to be an 80/20 per cent collaboration with the Netherlands Organisation for the Advancement of Science. A program of site tests considered Mauna Kea in Hawaii, the Pinaleno Mountains in Arizona, and a site in Chile. Ultimately Mauna Kea was chosen as the preferred site. The NNTT is a unique facility as plans for a similar telescope by the US collapsed in 1982.

Related Topics:
Research Council - PPARC - Mauna Kea - Hawaii - Pinaleno Mountains - Arizona - Chile - 1982

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The final specifications called for the "world's largest telescope optimised for submillimetre wavelengths." It was to be a parabolic 15-metre antenna comprised of 276 individually adjustable panels with a surface accuracy of less than 50µm. It would be an altitude-azimuth mounted Cassegrain telescope with a tertiary mirror to direct the incoming radiation onto a number of different receivers. The antenna and mountings were to be protected from the elements by a co-rotating carousel with a transparent membrane stretched across the

Related Topics:
Antenna - Altitude-azimuth - Cassegrain telescope

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carousel aperture. Building work started in 1983 and went well apart from a small delay caused by the hijacking of the ship carrying the telescope across the Pacific by modern-day pirates. The telescope saw first light in 1987. The name for the final facility was changed to the James Clerk Maxwell Telescope.

Related Topics:
1983 - Pacific - Pirates - 1987

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The JCMT is currently funded under a tripartite agreement between the United Kingdom (55 per cent), Canada (25 per cent), and the Netherlands (20 per cent). The telescope itself is operated by the Joint Astronomy Centre (JAC), from Hilo, Hawaii. The telescope site agreement with the University of Hawaii provides observer accommodation and infrastructure in exchange for open access to international proposals and 10 per cent of the observing time for the University's own projects. Proposals for telescope usage are submitted to one of the national Telescope Allocation Groups (TAGs) and if successful are awarded time in the next six-monthly semester.

Related Topics:
United Kingdom - Canada - Netherlands - Joint Astronomy Centre - Hilo - University of Hawaii

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