The Lovell Telescope ( ) is a radio telescope at Jodrell Bank Observatory, near Goostrey, Cheshire, in the north-west of England. When construction was finished in 1957, the telescope was the largest steerable dish radio telescope in the world at 76.2 m (250 ft) in diameter; it is now the third-largest, after the Green Bank telescope in West Virginia, United States, and the Effelsberg telescope in Germany. It was originally known as the "250 ft telescope" or the Radio Telescope at Jodrell Bank, before becoming the Mark I telescope around 1961 when future telescopes (the Mark II, III, and IV) were being discussed. It was renamed to the Lovell Telescope in 1987 after Sir Bernard Lovell, and became a Grade I listed building in 1988. The telescope forms part of the MERLIN and European VLBI Network arrays of radio telescopes.
Both Bernard Lovell and Charles Husband were knighted for their roles in creating the telescope. In September 2006, the telescope won the BBC's online competition to find the UK's greatest "Unsung Landmark". 2007 marked the 50th anniversary of the telescope.
If the air is clear enough, the Mark I telescope can be seen from high-rise buildings in Manchester such as the Beetham Tower, and from as far away as the Pennines, Winter Hill in Lancashire, Snowdonia, Beeston Castle in Cheshire, and the Peak District. It can also be seen from south-facing windows of the Terminal 1 restaurant area and departure lounges of Manchester Airport.
Construction
Conception and construction of the Mark I
Bernard Lovell built the Transit Telescope at Jodrell Bank in the late 1940s. This was a -diameter radio telescope that could only point directly upwards; the next logical step was to build a telescope that could look at all parts of the sky so that more sources could be observed, as well as for longer integration times. Although the Transit Telescope had been designed and constructed by the astronomers that used it, a fully steerable telescope would need to be professionally designed and constructed; the first challenge was to find an engineer willing to do the job. This turned out to be Charles Husband, whom Lovell first met on 8 September 1949.
Two circular 15" turret drive gear sets and associated pinions from 15-inch (38-cm) gun turrets were bought cheaply in 1950; these came from the World War I battleships HMS Revenge and Royal Sovereign, which were being broken up at the time. The bearings became the two main altitude rotator bearings of the telescope, with the appropriate parts of the telescope being designed around them. Husband presented the first drawings of the proposed giant, fully steerable radio telescope in 1950. After refinements, these plans were detailed in a "Blue Book", which was presented to the DSIR on 20 March 1951; the proposal was approved in March 1952.
Construction began on 3 September 1952. The foundations for the telescope were completed on 21 May 1953 after being sunk into the ground. It then took until mid-March 1954 to get the double railway lines completed because of their required accuracy. The central pivot was delivered to the site on 11 May 1954, and the final bogie in mid-April 1955.
The telescope bowl was originally going to have a wire mesh surface to observe at wavelengths between 1 and 10 meters (3.2 and 32 feet), so frequencies between 30 and 300 MHz; this was changed to a steel surface so that the telescope could observe at the 21 cm (8 in) hydrogen line, which was discovered in 1951. Also, in February 1954 Lovell and the Air Ministry met to see if funding could be made available for improving the accuracy of the dish so that it could be used on centimetre wavelengths, for research at these wavelengths for the Ministry as well as "other purposes". Although the funding was not ultimately made available from the Air Ministry, the planning process had already progressed, so this improvement was made anyway.