William Herschel Telescope

William Herschel Telescope
The William Herschel Telescope building
Alternative namesWHT
Location(s)Province of Santa Cruz de Tenerife, Canary Islands, Spain
Coordinates28°45′38″N 17°52′54″W / 28.76066°N 17.88174°W / 28.76066; -17.88174
Altitude2,344 m (7,690 ft)
Diameter4.2 m (13 ft 9 in)
Secondary diameter1.0 m (3 ft 3 in)
Collecting area13.8 m2 (149 sq ft)
Websitewww.ing.iac.es//Astronomy/telescopes/wht/
Location of William Herschel Telescope
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The William Herschel Telescope (WHT) is a 4.20-metre (165 in) optical and near-infrared reflecting telescope located at the Roque de los Muchachos Observatory on the island of La Palma in the Canary Islands, Spain. The telescope, which is named after William Herschel, the discoverer of the planet Uranus, is part of the Isaac Newton Group of Telescopes. It is funded by research councils from the United Kingdom, the Netherlands and Spain.

At the time of construction in 1987, the WHT was the third largest single optical telescope in the world. It is currently the second largest in Europe, and was the last telescope constructed by Grubb Parsons in their 150-year history.

The WHT is equipped with a wide range of instruments operating over the optical and near-infrared regimes. These are used by professional astronomers to conduct a wide range of astronomical research. Astronomers using the telescope discovered the first evidence for a supermassive black hole (Sgr A*) at the centre of the Milky Way, and made the first optical observation of a gamma-ray burst. The telescope has 75% clear nights, with a median seeing of 0.7".