Roque de los Muchachos Observatory

The Roque de los Muchachos Observatory occupies the summit ridge of La Palma, the north-westernmost of the Canary Islands, at around 2,400 metres above the Atlantic. Run by the Instituto de Astrofísica de Canarias, it was inaugurated on 29 June 1985 in the presence of the Spanish royal family and six European heads of state, and it has since become one of the great astronomical sites of the world, generally ranked second only to Mauna Kea in the northern hemisphere for optical and infrared work. The reason lies below the domes: the island's position in mid-ocean and the steady trade winds produce a layer of cloud between about 1,000 and 2,000 metres, a white sea that smothers the lights of the coast and leaves the summit in clear, still, dry air.

The telescopes are scattered along the ridge like a small town of white and silver towers. The largest is the Gran Telescopio Canarias, whose segmented mirror 10.4 metres across made it the world's largest single-aperture optical telescope; its first stone was laid in 2000. Around it stand the 4.2-metre William Herschel Telescope, the Isaac Newton Telescope, the Nordic Optical Telescope, the robotic Liverpool Telescope and the Swedish Solar Telescope, as well as the two dish-like MAGIC telescopes and the first Large-Sized Telescope of the Cherenkov Telescope Array, which hunt for the faint flashes of light made when gamma rays strike the atmosphere. Institutions from many countries work here side by side, which gives the mountaintop an unusually international feel.

The darkness is protected by law. Spain's Law 31/1988, the so-called Sky Law, limits outdoor lighting, radio transmitters and polluting industry on La Palma and on the part of Tenerife that faces it, and was the first law anywhere written to protect an observatory. As a result the whole island has unusually dark night skies, and stargazing has become part of its identity.

The setting is spectacular in its own right. The observatory stands on the rim of the Caldera de Taburiente, a vast eroded crater that opens beneath the summit, and on many days the cloud sea fills the horizon on every side. The telescopes themselves are working research instruments.

Getting there

The observatory lies about 12 km in a straight line from Los Llanos de Aridane, though the mountain roads make the trip much longer. The nearest airport is La Palma (SPC), about 20 km away on the east coast. There is no regular bus to the summit, so visitors drive themselves, take a taxi or join an organised tour; from Santa Cruz de La Palma the drive takes around an hour and twenty minutes on a road with many hairpin bends.