arriving at a rate of five to 10 per hour. When the V-2 attacks ceased, the echoes did not; Hey concluded that meteor trails were responsible and that radar could be used to track meteor streams, and could of course do so by day as well as by night. When he tried to increase the sensitivity of his radar in order to track V-2s from a greater distance, he rediscovered the cosmic radio noise that Karl Jansky and Grote Reber had found in the 1930s. Hey's results of 1942 and 1944 could not be published until after the war. From 1945 to 1947, Hey used AORG's radars in Richmond Park to research his wartime radio astronomical discoveries further. The Richmond Park installation thus effectively became the first radio observatory in Britain. Hey's main colleagues in this work were John Parsons (1918–1992), an electrical and mechanical engineer; Gordon Stewart (1919–2003), an electrical engineer; and James Phillips (1914–2003), a mathematician, who like Hey had been a schoolmaster before the war. In 1946 the Sun became active again, and the group confirmed sunspots and solar flares as the source of the emissions. In 1945 and 1946 they confirmed radar echoes from meteors, and derived methods to derive meteor shower radiants from the echoes, so discovering the first daytime meteor shower. In 1945 and 1946 they mapped the intensity of cosmic radio noise across the sky. In February 1946 they discovered a strong source in Cygnus which scintillated rapidly. Hey realised that the scintillation meant that the source must be compact, and suggested that it was a 'radio star'. It was later shown to be Cygnus A, a radio galaxy. This was, after Hey's discovery of the radio Sun, the first discovery of a specific astronomical radio source. During this period visitors to Hey at Richmond Park included Bernard Lovell, whom Hey helped to establish his radio observatory at the University of Manchester, and Jack Ratcliffe, under whom Martin Ryle and Antony Hewish established radio astronomy at Cambridge. Hey's observatory in Richmond Park was closed in 1947. Hey became Head of the AORG in 1949. From 1952 he returned to ADRDE, which later became part of the Royal Radar Establishment at Malvern, Worcestershire, where he also continued his radio astronomical observations. At his observatory at Defford, Worcestershire, he built a variable-spacing radio interferometer, with which he briefly parallelled Martin Ryle's research at Cambridge. From