Title: Lovell Telescope Detects Sputnik
Podcaster: Stuart Lowe and Tim O’Brien
Organization: Jodrell Bank Centre for Astrophysics. http://www.jodrellbank.manchester.ac.uk/
Description: On this day in 1957, the newly constructed Mark I telescope at Jodrell Bank became involved in the dawn of the space age when it picked up a radar echo from the rocket that had carried Sputnik 1 into space. We tell you about the history of the famous telescope, which was later named after its founder Sir Bernard Lovell, and describe some of the astronomical observations it has been involved with since.
Bio: Stuart Lowe and Tim O’Brien both work at The University of Manchester’s Jodrell Bank Centre for Astrophysics. Stuart works on instrumentation for ESA’s Planck spacecraft and Tim studies exploding stars using telescopes around the world and in space.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by the National Radio Astronomy Observatory, celebrating Five Decades of Training Young Scientists through summer programs. Explore the hidden universe in radio at www.nrao.edu.
Stuart: Hello and welcome to the 12th October edition of the 365 Days of Astronomy. I’m Stuart Lowe and joining me is Dr Tim O’Brien from the Jodrell Bank Centre for Astrophysics in the UK.
Stuart: Now, on this day 52 years ago the UK’s giant radio telescope at Jodrell Bank picked up a radar echo from the rocket that, 8 days earlier, had carried into space Sputnik 1 – the world’s first artificial satellite. The launch took the world by surprise but the story of Jodrell Bank’s involvement had started in the 1930s.
Tim: The story really begins back in the 1930s with the birth of invisible astronomy. For thousands of years people had been looking at the skies with their eyes picking up visible light. For the past 400 years we’ve been able to use telescopes to get a clearer view. But it was in the 1930s that we first opened up the spectrum beyond the visible regime. The first bit of spectrum to be opened up was the radio window. The pioneer in this field was Karl Jansky who was the first to detect radio emission coming from space. He was quickly followed up by another American – Grote Reber – the first to build a parabolic dish.
Stuart: He was also the world’s first amateur radio astronomer.
Tim: He was. Neither of these guys were professional astronomers. Reber was the first real radio astronomer because Jansky hadn’t done much astronomy with his discovery. Reber actually mapped the radio sky. Then there wasn’t really any more progress until after World War II and that was where the story of Jodrell Bank began in 1945. Bernard Lovell, a physicist who’d been working at Manchester University before the war, came back at the end of the war and wanted to use the radar techniques that had been developed during the war to do some physics. He was interested in cosmic rays: particles that crash into our atmosphere at high speed. He thought he could bounce a radar off the trail they left in the atmosphere and get an echo back. So he set up his kit out at Jodrell in 1945 and he started making observations. They quickly realised that the echoes they were getting were from shooting stars. He also quickly realised that if he was going to detect these cosmic rays he needed a much bigger telescope with a much bigger collecting area because the signals were far weaker than he had originally expected. So they came up with the idea for a giant dish. It was basically a mesh 218ft across – the world’s largest radio telescope at the time. They built it in a field at Jodrell 20 miles south of Manchester in the UK. It pointed straight up – it didn’t move around – it looked at a strip of sky that passed by overhead much as the Arecibo radio telescope does today. They did some amazing things with that telescope. They picked up radio waves coming from the Andromeda Galaxy, they recovered the remnant of the supernova that Tycho Brahe had seen in 1572 which had faded away 400 years before. They were the first to pick it up again as a radio source. But the big problem with that telescope was that it did just point straight upwards. It was quite limited in that sense. So over 24 hours you just see a strip of sky that goes by overhead. They needed a similarly giant telescope (to get the sensitivity) but one that could point in different directions. That is where the idea for the Mark I telescope (now called the Lovell Telescope after Sir Bernard Lovell) was born.
Stuart: I think they got some bridge builders to design it.
Tim: Yes. Sir Bernard came up with this idea – he wanted this giant telescope that he could tip around and point anywhere. He went to various engineers and said, “Can you help me? This is my idea, can you make it a reality?” He was turned down for various reasons. Some people thought it couldn’t be done. Other people were too busy with rebuilding after the war. Eventually he found Charles Husband who was an engineer who had been building bridges. He said, “Yes, I’ll give it a go!” They came up with this idea and got a grant from the Government for £335,000.
Stuart: How much is that in today’s money?
Tim: It depends how you calculate it but it’s at least a factor 20. So a minimum of £6 million today and relative to the total economy may be as much as £20 million. It was a significant project at the time, nobody had ever built anything like that in the world before. They started in 1952 and it took 5 years to get close to completion. But by that time, since it was a project that nobody had ever attempted before, the cost had escalated. They’d actually gone over budget by £260,000 on the original project estimate of £335,000. It was a significant overspend and the project was in serious trouble.
Stuart: Here is Sir Bernard Lovell to tell us about those days in the summer of 1957.
Sir Bernard Lovell: So there we were with the telescope incomplete, no connection to the control room, and I remember saying to Hanbury-Brown, “We need a miracle to save us.” It is strange how one remembers that. I think a week or 10 days later the Sputnik was launched.
Tim: On 9th October they managed to get the telescope controlled from the control room remotely. They got a small radar transmitter that had been used for meteor work and they carried it up into the swinging lab – a small laboratory that hangs below the bowl of the telescope so as the telescope tips up and down, it stays level. They carried that transmitter up into there, ran the cables up to the focus of the telescope so that they could send out the radio signal. On the first night – the 11th October – they started to search for echoes. They saw lots of meteors but they couldn’t be sure that any of the echoes they received were from the rocket itself. On Saturday 12th October, just before midnight, they finally saw it.
Sir Bernard Lovell: We had this wonderful echo from the carrier rocket when it was traveling over the Lake District at about 17,000 mph I think. A wonderful echo. I’ve never forgotten it. I can see it now. We were looking at meteors… and then this echo: whang! Right across the tube like that. Something no man had yet seen.
Stuart: And this signal, in a field in the Cheshire countryside, caused huge public and media interest around the world. However, it still took some time for the debt to be cleared. The Government did agree to pay for half the amount – about £130,000 – and there was even a fund raising appeal launched. The public contribution to that was quite immense – even school children were sending in their pocket money. But it was only following Jodrell’s role in the tracking of the Soviet and American Moon rockets and the remote control of Pioneer V – the interplanetary probe – in 1960, that led to the final debt being paid off in a rather surprising manner.
Sir Bernard Lovell: So Lord Nuffield came on the telephone and said, “How much money is owing on that telescope of yours?” And I said, I was a bit confused, “I think it is about £80,000.” And he said, “Is that all? I’ll send you a cheque to pay it off.” I tried to thank him and he said, “That’s alright my boy, you haven’t done too badly.”
Tim: Now the telescope continued to play a significant role in a number of different space missions throughout the 1960s, including picking up the first pictures ever to be sent from the surface of the Moon. The Russians landed a spacecraft on the Moon in 1966 – Luna 9 – and it took photographs of the surface and they were sent back to Earth. The telescope here at Jodrell was used to eavesdrop on those signals. Somebody spotted that the type of signal was like that of an early fax machine, plugged one of them into the back of the telescope and out came a picture of the Moon which made it onto the front page of the newspapers the next day. So this sort of role in space tracking had a very high public profile but was only a small percentage of the time the telescope was actually used for. Most of the time it was doing astronomy, its original purpose. It played a significant role in the discovery of quasars – distant galaxies with supermassive black holes at their cores. Again, played another major role in the discovery of gravitational lenses – distant objects that bend light around them as predicted by Einstein. It made major progress in the study of pulsars – the dead remnants of exploded stars – exotic dense neutron stars. Even today it’s playing a significant role in astronomy. In recent years it has been completely refurbished. It’s had a whole new surface put on. Complete new drive systems. Receivers that we cool down to only 20 degrees above absolute zero. It’s actually more capable now than it ever has been. Right now it’s about to embark on a new phase of its career. It’s at the heart of an upgraded array of radio telescopes here in the UK that we call e-MERLIN. It’s actually 7 radio telescopes, including the Lovell, that we’ve now connected with optical fibres. It’s going to create this incredibly sensitive radio telescope which will produce images of the radio sky with the same sharpness as the Hubble Space Telescope.
Stuart: Thanks Tim. It’s great to know that 52 years after it first came to the public’s attention, at the dawn of the space age, the Lovell Telescope is still producing fantastic results. If you want to hear the full interview with Sir Bernard Lovell (and a previous interview in parts 1, 2 and 3) visit our website at www.jodcast.net.
End of podcast:
365 Days of Astronomy
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