The James Clerk Maxwell Telescope (JCMT) is a submillimetre-wavelength radio telescope at Mauna Kea Observatory in Hawaii, US. The telescope is near the summit of Mauna Kea at . Its primary mirror is 15 metres (16.4 yards) across: it is the largest single-dish telescope that operates in submillimetre wavelengths of the electromagnetic spectrum (far-infrared to microwave). Scientists use it to study the Solar System, interstellar dust and gas, and distant galaxies. The JCMT started operations in 1987, and was funded until February 2015 by a partnership between the United Kingdom and Canada, and the Netherlands. It was operated by the Joint Astronomy Centre and was named in honour of mathematical physicist James Clerk Maxwell. In March 2015 the operation of the JCMT was taken over by the East Asian Observatory. Funding is provided by the National Astronomical Observatory of China, National Astronomical Observatory of Japan, Korea Astronomy and Space Science Institute, and the Academia Sinica Institute of Astronomy and Astrophysics of Taiwan. The telescope was combined with the Caltech Submillimeter Observatory next to it to form the first submillimetre astronomical interferometer. This success was important driving the construction of the later Submillimeter Array and the Atacama Large Millimeter Array (ALMA) interferometers. In recent years the JCMT has also taken part in Event Horizon Telescope observations, which produced the first direct image of a black hole. The JCMT was also involved in the discovery of phosphine, a potential biomarker, in the atmosphere of Venus. History In the late 1960s, the Astronomy Committee of the UK's Science Research Council (SRC, the forerunner of STFC) considered the importance of astronomical observations at submillimetre and millimetre wavelengths. After a series of proposals and debates, in 1975, the SRC millimetre steering committee concluded that it would be possible to construct a 15-metre diameter telescope capable of observing at wavelengths down to 750–800 µm. 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. Site tests were made at Mauna Kea in Hawaii, the Pinaleno Mountains in Arizona, and a site in Chile; and Mauna Kea was chosen. The NNTT was to be larger and with more instruments than competing telescopes such as the CSO and SMT. The final specifications called for the "world's largest telescope optimised for submillimetre wavelengths". It was to be a parabolic 15-metre antenna composed