The Mullard Radio Astronomy Observatory (MRAO) is located near

Cambridge Cambridge ( ) is a university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cambridge bec ...

, UK and is home to a number of the largest and most advanced aperture synthesis

radio telescope A radio telescope is a specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency ...

s in the world, including the One-Mile Telescope, 5-km

Ryle Telescope {{Infobox telescope The Ryle Telescope (named after Martin Ryle, and formerly known as the 5-km Array) was a linear east-west radio telescope array at the Mullard Radio Astronomy Observatory. In 2004, three of the telescopes were moved to creat ...

, and the Arcminute Microkelvin Imager. It was founded by the

University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...

and is part of the Cambridge University, Cavendish Laboratories, Astrophysics Department.

History

Radio interferometry started in the mid-1940s on the outskirts of

, but with funding from the Science Research Council and a corporate donation of £100,000 from Mullard Limited, a leading commercial manufacturer of

thermionic valve A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as a ...

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

. The observatory was founded under

Martin Ryle Sir Martin Ryle (27 September 1918 – 14 October 1984) was an English radio astronomer who developed revolutionary radio telescope systems (see e.g. aperture synthesis) and used them for accurate location and imaging of weak radio sourc ...

of the Radio-Astronomy Group of the

Cavendish Laboratory The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the School of Physical Sciences. The laboratory was opened in 1874 on the New Museums Site as a laboratory for experimental physics and is named ...

and was opened by Sir

Edward Victor Appleton Sir Edward Victor Appleton (6 September 1892 – 21 April 1965) was an English physicist, Nobel Prize winner (1947) and pioneer in radiophysics. He studied, and was also employed as a lab technician, at Bradford College from 1909 to 1911. He ...

on 25 July 1957. This group is now known as the Cavendish Astrophysics Group.

Location

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 The Cambridge Low-Frequency Synthesis Telescope (CLFST) is an east-west aperture synthesis radio telescope currently operating at 151 MHz. It consists of 60 tracking yagis on a 4.6 km baseline, giving 776 simultaneous baselines. These prov ...

. Due to this, the reconstruction of the railway line between Oxford and Cambridge will follow a new alignment at this point.

Telescopes

Gallery

The following photographs (except for the last 2 items) were taken in June 2014: cmglee Cambridge MRAO station house.jpg, Platform and Lecture Room formerly part of Lord's Bridge Railway Station cmglee Cambridge MRAO AMI Large Array.jpg, Arcminute Microkelvin Imager - Large Array (AMI-LA) cmglee Cambridge MRAO AMI Small Array.jpg, Arcminute Microkelvin Imager - Small Array (AMI-SA) cmglee Cambridge MRAO CAT.jpg, Stitched panorama of the Cosmic Anisotropy Telescope enclosure cmglee Cambridge MRAO COAST.jpg, Part of the Cambridge Optical Aperture Synthesis Telescope cmglee Cambridge MRAO COAST bunker.jpg, The interior of the bunker of the Cambridge Optical Aperture Synthesis Telescope cmglee Cambridge MRAO MERLIN.jpg, The receiver from the e-MERLIN array cmglee Cambridge MRAO CLFST.jpg, Surviving Yagi antennas of the Cambridge Low Frequency Synthesis Telescope cmglee Cambridge MRAO Half Mile Telescope.jpg, Two Half-Mile Telescopes cmglee Cambridge MRAO IPS Array.jpg, Remains of the Interplanetary Scintillation Array cmglee Cambridge MRAO One Mile Half Mile 4C.jpg, One-Mile Telescope (left), two of the Half-Mile Telescope (centre) and the remains of the 4C Array (right) cmglee Cambridge MRAO 4C Array.jpg, Remains of the 4C Array, with One-Mile Telescope in the background Mullard el34.jpg, Mullard EL34 Power

Pentode A pentode is an electronic device having five electrodes. The term most commonly applies to a three-grid amplifying vacuum tube or thermionic valve that was invented by Gilles Holst and Bernhard D.H. Tellegen in 1926. The pentode (called a ''trip ...

. Mullard produced up to 40% of thermionic valves used by Britain during 1939-1945 War MRAO Plaque.JPG, Mullard Radio Astronomy Observatory plaque

References

Notes

Sources

The Mullard Radio Astronomy Observatory webpageImage from Google maps
showing the One-Mile, Half Mile,

4C Array The 4C Array is a cylindrical paraboloid radio telescope at the Mullard Radio Astronomy Observatory, near Cambridge, England. It is similar in design to the Molonglo Observatory Synthesis Telescope. It is 450 m long, 20 m wide, with a second, mov ...

MERLIN Merlin ( cy, Myrddin, kw, Marzhin, br, Merzhin) is a mythical figure prominently featured in the legend of King Arthur and best known as a mage, with several other main roles. His usual depiction, based on an amalgamation of historic and leg ...

COAST The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in n ...

, CAT and Ryle telescopes.
Subterranea Britannica entry for Lords Bridge Forward Filling Depot (also Air Ammunition Park)Subterranea Britannica entry for Lords Bridge Station
{{Authority control Radio telescopes Astronomical observatories in England Buildings and structures in Cambridgeshire Cavendish Laboratory