Editing Interplanetary Scintillation Array (section)

{{Short description|Phased array radio telescope built in 1967}}
{{Use dmy dates|date=April 2022}}
{{more citations needed|date=July 2017}}
{{Infobox telescope}}
[[File:Chart Showing Radio Signal of First Identified Pulsar.jpg|thumb|upright|Chart on which [[Jocelyn Bell Burnell]] first recognised evidence of a [[pulsar]], later designated [[PSR B1919+21]] (exhibited at [[Cambridge University Library]]) ]]

The '''Interplanetary Scintillation Array''' (also known as the '''IPS Array''' or '''Pulsar Array''') is a [[radio telescope]] that was built in 1967 at the [[Mullard Radio Astronomy Observatory]], in [[Cambridge|Cambridge, United Kingdom]], and was operated by the [[Cavendish Astrophysics Group]]. The instrument originally covered 4 [[acre]]s (16,000 m<sup>2</sup>). It was enlarged to 9 acres in 1978, and was refurbished in 1989.

The array operates at a [[radio frequency]] of 81.5&nbsp;MHz (3.7 m [[wavelength]]), and is made up of 4,096 [[dipole antenna]]s in a [[phased array]]. Using 14 beams, it can map the northern sky in one day. The observatory's staff use [[sheep]] to keep grass away from the antennas because a [[lawn mower]] cannot fit in the spaces.

[[Antony Hewish]] designed the IPS Array to measure the high-frequency fluctuations of radio sources, originally for monitoring [[interplanetary scintillation]]. Hewish received a [[Nobel Prize]] after the high time-resolution of the array allowed the detection of [[pulsars]] by [[Jocelyn Bell]] in 1967.<ref>{{cite web |title=The First Pulsar |url=https://astrobites.org/2017/09/15/the-first-pulsar/ |website=[[Astrobites]] |date=15 September 2017}}</ref>

The IPS Array has more recently been used to track and help forecast interplanetary weather, and specifically to monitor the solar wind. It is now essentially retired, and has lost a significant fraction of its area.