James Clerk Maxwell Telescope

Research facility highlights

Credit: Joint Astronomy Centre

The James Clerk Maxwell Telescope (JCMT) was built jointly by the United Kingdom and the Netherlands, and is funded by Canada, the U.K. and the Netherlands. Located near the summit of Mauna Kea in Hawaii at an altitude of 4200m and operated from the Joint Astronomy Centre in Hilo, Hawaii, the JCMT is used by astronomers from the funding countries, as well as by scientists from around the world. The facility also reserves a portion of observing time for the University of Hawaii.

Named after the pioneering Scottish physicist who gave us a fundamental understanding of electricity and magnetism, the JCMT opened a new window on the universe by allowing ground-based access to the submillimetre portion of the electro-magnetic spectrum.

What we offer

The JCMT is the largest single-dish astronomical telescope designed specifically to operate in the submillimetre wavelength region of the spectrum; it is capable of detecting radiation within the range of about 0.3 to 2 mm. The telescope’s 15-metre diameter primary reflector is made up of 276 individual lightweight panels, each one consisting of a thin aluminium skin bonded to an aluminium honeycomb and attached at three points to the backing structure of the antenna. The dish surface accuracy is routinely measured and adjusted as needed to ensure optimal performance.

The telescope’s suite of instruments includes a number of receivers, which can be simultaneously accommodated on the telescope. The heterodyne receivers, covering the atmospheric windows between 215 and 680 GHz, are mounted in the Cassegrain cabin; the continuum bolometer array instrument, SCUBA-2, and the heterodyne array receiver, HARP, are located in the Nasmyth platforms at the ends of the elevation bearing.

Access and use

Astronomers have used the JCMT to gather unique information about many types of objects, including the Sun, comets, planets, molecular clouds, galaxies, quasars and the submm background. Analyses of their findings have helped scientists answer questions about these objects that would otherwise be impossible to answer, including making critical determinations of source luminosity, chemical composition, temperature, dynamics, and magnetic fields. The telescope is scheduled on a semester basis for ordinary proposals and semi-annual calls for proposals are issued. 65% of the available telescope time is reserved for the conduct of the JCMT Legacy Surveys to be carried out with SCUBA-2.