Editing Cambridge Optical Aperture Synthesis Telescope (section)

{{Short description|English astronomical interferometer observatory}}
{{Use dmy dates|date=April 2022}}
{{Infobox telescope}}
[[File:cmglee Cambridge MRAO COAST.jpg|thumb|250px|Part of COAST and the exterior of its bunker in June 2014]]

'''COAST''', the '''Cambridge Optical Aperture Synthesis Telescope''', is a multi-element optical [[astronomical interferometer]] with baselines of up to 100 metres, which uses [[aperture synthesis]] to observe stars with [[angular resolution]] as high as one thousandth of one [[arcsecond]] (producing much higher resolution images than individual telescopes, including the [[Hubble Space Telescope]]). The principal limitation is that COAST can only image bright [[star]]s.

COAST was the first long-baseline interferometer to obtain high-resolution images of the surfaces of stars other than Sun (although the surfaces of other stars had previously been imaged at lower resolution using [[aperture masking interferometry]] on the [[William Herschel Telescope]]).

The COAST array was conceived by [[John E. Baldwin]] and is operated by the [[Cavendish Astrophysics Group]]. It is situated at the [[Mullard Radio Astronomy Observatory]] in [[Cambridgeshire]], [[England]].