Monument record 7756/15 - Jodrell Bank Observatory: 71MHz Searchlight Aerial

<1> Historic England, 2011, The National Heritage List for England, 1443133 (Web Site). SCH6528.

The first new member of staff to join Lovell’s research team was John Atherton Clegg, who joined him in 1946, bringing an extensive knowledge of radar aerials. Lovell suspected that meteors reflected radar signals and so at this time he also enlisted the help of amateur astronomer, JP Manning Prentice, who was then Director of the Meteor Section of the British Astronomical Association. This was a move which was to change Lovell’s post-war career from physicist to astronomer. In August 1946 Lovell, Clegg and Prentice observed the Perseid meteor shower, hoping to discover whether the echo rate of the radar equipment was related to the known meteor activity. The results were promising, but required further research to clarify the complexity of the results. Prentice suggested observing the Giacobinid meteor shower on the night of the 9–10th October 1946. Clegg realised that in order to do this an aerial was needed which could be moved continuously both in elevation and azimuth (vertical altitude and side to side to define the apparent position of an object in the sky relative to a specific observation point). He set about creating the Searchlight Aerial, using the mount from a searchlight loaned by the army for its excellent turning mechanism. This was positioned near to the Park Royal trailer, which had become permanently stuck in the mud when being moved towards the north end of the site. Clegg built an array of five 7-element Yagi aerials on the mount. The development of this equipment by Lovell and Clegg involved making substantial changes and additions to radar equipment from its war-time form. It was a great success in observing the ionised trails of the Giacobinid meteor shower, and was then shortly developed to determine the radiant points of meteors. Lovell wrote ‘The Searchlight Aerial survived for many years and became the aerial system for a variety of subsequent research programs'. Eventually, this splendid aerial system was superseded but the rusty remnants of the searchlight base remain as a reminder of an epic night in the early history of Jodrell Bank’. In 1947 Lovell and Clegg presented their findings to the Royal Astronomical Society, revealing a new revolutionary astronomical technique.

The Searchlight Aerial was used as a backdrop to a black and white photograph of Lovell and his research team thought to have been taken on the occasion of his appointment as Professor of Radio Astronomy in 1951.

The remains of the searchlight mount survives, but the aerial arrays are no longer present.

<2> Chris Blandford Associates, 2016, Jodrell Bank Observatory, Conservation Management Plan (Client Report). SCH8560.

<3> Huntings Surveys Ltd, 1971-1973, 1971-1973 County Survey, Run 37, no.1145-6 (Aerial Photograph). SCH4881.

Visible on this photograph.