# 4C Array

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{{Short description|Radio telescope in Cambridge, England}}
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The '''4C Array''' is a cylindrical paraboloid [radio telescope](/source/radio_telescope) at the [Mullard Radio Astronomy Observatory](/source/Mullard_Radio_Astronomy_Observatory), near Cambridge, England. It is similar in design to the [Molonglo Observatory Synthesis Telescope](/source/Molonglo_Observatory_Synthesis_Telescope). It is 450 m long, 20 m wide, with a second, moveable element (now mostly removed; some of it is still visible, beyond [COAST](/source/Cambridge_Optical_Aperture_Synthesis_Telescope_(COAST))).{{Citation needed|date=January 2024}} The first large aperture synthesis telescope (1958), it was also the first new instrument to be built at [Lord's Bridge](/source/Lord's_Bridge_(Cambridgeshire)), after the [Observatory](/source/Mullard_Radio_Astronomy_Observatory) was moved there in 1957, and needed {{convert|64|km|mi|abbr=on}} of reflector wire (since removed).{{Citation needed|date=January 2024}} The 4C operated at 178&nbsp;MHz (1.7 m), and located nearly 5000 sources of the [4C (4th Cambridge) catalogue](/source/Fourth_Cambridge_Survey) published in 1965 and 1966, which helped establish the evolution of the radio galaxy population of the universe.<ref>{{Cite web |last=Longair |first=Malcolm |title=A Brief History of Radio Astronomy in Cambridge |url=https://www.astro.phy.cam.ac.uk/about/history?}}</ref> The telescope is now inoperable.<ref>{{Cite web |date=2019-09-11 |title=Report - - The 4C Array radio telescope – Mullard Observatory – Cambridge – August 2019 {{!}} Other Sites |url=https://www.28dayslater.co.uk/threads/the-4c-array-radio-telescope-mullard-observatory-cambridge-august-2019.120012/ |access-date=2025-11-13 |website=28DaysLater Urban Exploring Forums |language=en-GB}}</ref>

It is flanked to the northwest by the [Cosmic Anisotropy Telescope](/source/Cosmic_Anisotropy_Telescope) enclosure and to the south by the [One-Mile](/source/One-Mile_Telescope) and [Half-Mile Telescope](/source/Half-Mile_Telescope)s.{{Citation needed|date=January 2024}}

thumb|250px|none|One antenna of the One-Mile Telescope (left), two of the Half-Mile Telescope (centre) and the remains of the 4C Array (right) in June 2014

== References ==
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Category:Cavendish Laboratory
Category:Radio telescopes
Category:Interferometric telescopes
Category:Astronomical observatories in England

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Adapted from the Wikipedia article [4C Array](https://en.wikipedia.org/wiki/4C_Array) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/4C_Array?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.