When I joined in 1948, the name radio astronomy didn’t even exist. What had happened was that Ratcliffe and Martin Ryle knew each other through working at TRE Malvern [Telecommunications Research Establishment], and Ratcliffe knew that Martin was… was very bright and would be a good person to have in… in his research team when he… when he returned to the Cavendish. And he attracted Martin Ryle here, Martin Ryle had been an Oxford man and I think Jack Ratcliffe had been… who was head of the ionosphere group at that time, and as I think I said yesterday, Ratcliffe was originally a student of Edward Appleton who’d been a Cavendish man and Edward Appleton got the Nobel Prize for discovering the ionosphere. So there was a strong tradition of ionospheric physics here in the Cavendish, and when Ratcliffe came back to restart all that and build a research team, he was also interested in… he was very interested in Martin Ryle because he’d met him and knew how bright he was. But Martin Ryle wasn’t interested in the ionosphere and I think what happened was that Ratcliffe said, well, why not have a look at these radio waves from the Sun, which was a wartime discovery which only became known after the war because it was kept secret at the time. But in 1942 James Hey, who was then an operational… operational research person working with the anti-aircraft actually, and he was in charge of… of South Coast radars and they were all put out of action on… in early February 1942 by strange radiation coming in. It was a dull day, one doesn’t know where this radiation was coming from, but all the radars were swamped by a noise interference. And this happened soon after the famous episode when the pocket battleships, which had been trying to get back home to Germany after being damaged in the… off the Spanish coast, I think it was, the Scharnhorst and the Gneisenau, they were called, they made a dash up through the Channel in bad weather and escaped detection and… and made their way through, before we were aware of them. And that was because the Germans set up an intense barrage which… which blinded our coastal radars and we couldn’t… we couldn’t spot them going through the Channel, and they were well into the North Sea before they were actually found. And I… I think we sent some ancient naval Swordfish, you know, lumbering after them and they did their best, but that wasn’t good enough. Well, now when the South Coast radars were again swamped, it was immediately thought, well, what’s going on, is there something else, are they launching an invasion or something? And it wasn’t and… and Hey discovered that his… the radars had, in fact, been pointing more or less at the Sun during that time and he got on to the Royal Greenwich Observatory who said, yes, there is an active sunspot group crossing the middle of the solar disk right now, and the connection was made that the Sun was emitting, could emit bursts of radio which were strong enough actually to… to drown our radars. And this… this, I think, had been known by radio amateurs but it wasn’t widely known. There was a strange sort of interference which radio amateurs, hams, had been picking up also over… over the years, the pre-war years, and it was thought it might be something to do with the Sun. But, at any rate, Hey proved that it was and he himself began research, this was before the research groups were actually disbanded. I’m talking now about sort of ’95… 1945 era when the war in Japan was winding up, and… and the war in Europe was… was over and you had all these research groups who’d been in radar wondering what to do. And Hey began to reinvestigate these radio waves from the Sun and he also discovered radio waves coming from the radio source Cygnus, Cygnus A as we now call it. Well, anyway, that… that was all the background when Ryle was looking around for… for university research, and when he came to Cambridge, Ratcliffe said, well, look, have a look at these radio waves from the… from the Sun, which Martin Ryle did. He started off using old wartime antennas and wartime receivers, actually, linking them together, and that’s when we started at the Old Rifle Range site, just a mile from here.