Work as part of the Harwell Heritage Project rediscovered a set of photographs and original artwork of the JCMT. Technical input from Malcolm Currie (RAL Space) and the loan of some wonderful little souvenirs of his time working on the telescope made an interesting display in the Library "airlock" April/May 2023.
The telescope is situated on the volcanic peak of Maunakea* in Hawaii and is the world's most successful single-dish telescope for observing sub-millimetre wavelengths in the electromagnetic spectrum. Since it began operating in 1987 it has been associated with a number of major scientific discoveries, and continues to do world-class science as part of programmes such as the Event Horizon Telescope. Until February 2015 JCMT was funded by a partnership between the UK, Canada and the Netherlands. It was then taken over by the East Asian Observatory and is funded by various national astronomy institutes from China, Japan, South Korea and Taiwan.
* The name Maunakea means "white mountain" because of the snow on its peak.
After a number of false starts, work on what was initially called the UK Millimetre-wave Telescope got underway in 1975. Detailed design work proceeded quite rapidly, but the issue of finding a site proved more difficult. Hawaii was the obvious choice but Maunakea is sacred land and the volcano is in a conservation area so the proposal to build a second telescope in addition to UKIRT (UK Infra Red Telescope) was controversial. Attention switched to La Palma in the Canary Islands and negotiations began. Then someone pointed out that if the telescope needed to get above the water vapour, La Palma simply wasn't high enough... but Maunakea was. Fortunately, circumstances in Hawaii had changed by this time so work recommenced on Maunakea.
JCMT was designed at Appleton then Rutherford Appleton Laboratories. Its 15 metre diameter dish comprises 276 curved aluminium reflecting panels which were fabricated at RAL to an accuracy of 24 microns (about the thickness of a piece of tissue paper). The fabrication of the steel for the telescope took place at a factory in Ijmuiden near Amsterdam, followed by a test assembly and development of the various drives. It was then shipped to Hawaii and by late 1985 the main parts were on the mountain with an enthusiastic team ready to do the assembly.
Many institutes contributed to the JCMT including the Netherlands Science Foundation (ZWO), the UK's SRC Appleton and Rutherford Laboratories, and the National Research Council, Canada.
To get to the telescope you drove about an hour from the JAC to Hale Pohaku then acclimate over-night to the 9300 feet (2800 metres) altitude. For the last half hour of your journey you wind your way through several switchbacks before emerging onto what looks very much like a lunar landscape. You were not allowed to stay long however -- for safety reasons there was a limit of 14 hours per night at the summit.
A remote-control centre (JROC) was established in 2013 to avoid the drive, have more time for observations and so make the telescope more productive. It is also much easier to think clearly at sea level than at 13400 feet (4000 metres).
The telescope was opened on Monday 27th April 1987 by HRH Prince Philip who unveiled a plaque and looked to be enjoying himself at the celebrations afterwards. The opening was mostly memorable for the fact that when the traditional "lever to start the first observation" was pressed, nothing happened because one of the VIP guests was leaning on the emergency stop button.
The steel-work for the enclosure was made in Bolton. The plan was to ship it to Hawaii using a large boat but that broke down so the shipping company subcontracted to a small freighter which set off on its voyage barely visible under the large pile of steel lashed to its deck. It all went quiet for several weeks then information was received that the freighter had not gone directly to Hawaii as planned, but rather to Holland where it loaded up with a second cargo... of high explosives. There was an additional delay before it could get through the Panama Canal whereupon it vanished again, probably to off-load the explosives in Ecuador.
By the time the freighter reached Hawaii the penalty clauses for late delivery were nearly equal to the total fee for the charter. The captain stopped outside the territorial waters and demanded full payment of the original price or he would off-load the steel into the sea. Fortunately JCMT staff were able to obtain a writ for piracy on the high seas so the US Coastguard went out, arrested the captain (at gunpoint!), took possession of the boat and towed it safely into Hilo.
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