Mullard Radio Astronomy Observatory


The Mullard Radio Astronomy Observatory (MRAO) is located near Cambridge, UK and is home to a number of the largest and most advanced aperture synthesis radio telescopes in the world, including the One-Mile Telescope, 5-km Ryle Telescope, and the Arcminute Microkelvin Imager. It was founded by the University of Cambridge and is part of the Cambridge University, Cavendish Laboratories, Astrophysics Department.

Mullard Radio Astronomy Observatory
One-Mile Telescope.jpg
Named afterMullard Edit this on Wikidata
LocationUnited Kingdom Edit this at Wikidata
Coordinates52°10′03″N 0°01′57″E / 52.1674°N 0.0326°E / 52.1674; 0.0326Coordinates: 52°10′03″N 0°01′57″E / 52.1674°N 0.0326°E / 52.1674; 0.0326
Mullard Radio Astronomy Observatory is located in the United Kingdom
Mullard Radio Astronomy Observatory
Location of Mullard Radio Astronomy Observatory
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West aerial of the One-Mile Telescope at MRAO


Radio interferometry started in the mid-1940s on the outskirts of Cambridge, but with funding from the Science Research Council and a corporate donation of £100,000 from Mullard Limited, a leading commercial manufacturer of thermionic valves.

Construction of the Mullard Radio Astronomy Observatory commenced at Lords Bridge Air Ammunition Park,[1] a few kilometres to the west of Cambridge.

The observatory was founded under Martin Ryle of the Radio-Astronomy Group of the Cavendish Laboratory, University of Cambridge and was opened by Sir Edward Victor Appleton on 25 July 1957. This group is now known as the Cavendish Astrophysics Group.


The observatory is located a few miles south-west of Cambridge at Harlton on a former ordnance storage site, next to the disused Oxford-Cambridge Varsity railway line.

A portion of the track bed of the railway, running nearly east-west for several miles, was used to form the main part of the "5km" radio-telescope and the Cambridge Low Frequency Synthesis Telescope. Due to this, the reconstruction of the railway line between Oxford and Cambridge will follow a new alignment at this point.


Telescope Year built Status
Arcminute Microkelvin Imager Large Array 2007 Active
Arcminute Microkelvin Imager Small Array 2004 Active
Very Small Array (moved to Tenerife in 1999) 1998 Active
Cosmic Anisotropy Telescope made first high-resolution maps of Cosmic Microwave Background fluctuations 1995 Decommissioned
Cambridge Optical Aperture Synthesis Telescope (COAST) first aperture synthesis at optical wavelengths 1993 Operated on clear nights
One receiver from the e-MERLIN array 1990 Active
Cambridge Low Frequency Synthesis Telescope (CLFST) 1980 Decommissioned
Ryle Telescope (formerly 5-Kilometre Telescope) 1971 Decommissioned
(repurposed for AMI LA in 2006)
Half-Mile Telescope 1968 Decommissioned
Interplanetary Scintillation Array discovered first pulsar 1967 Decommissioned
One-Mile Telescope 1964 Decommissioned
4C Array, first telescope at the Cambridge's new observatory, used to make the 4C catalogue 1958 Decommissioned


The following photographs (except for the last 2 items) were taken in June 2014:



  1. ^ "Subterranea Britannica - Lords Bridge".


  • Overview | Cavendish Astrophysics
  • Mullard Radio Astronomy Observatory (MRAO) on Google maps
  • Subterranea Britannica entry for Lords Bridge Forward Filling Depot (also Air Ammunition Park)
  • Subterranea Britannica entry for Lords Bridge Station