The Parkes Radio Telescope in New South Wales Australia after it had been fitted with the new Multi-beam receiver system designed to pick up the Hydrogen signals from galaxies with about a thousand times the speed of any previous instrument. It has 13 separate dual-beams and 26 receivers cooled down close to absolute zero (minus 273 degrees C) up in the receiver cabin which is the size of a small house. Up there the very weak signals are mixed with a maser and the lower frequency output signals are sent down to the tower where they are processed by specially designed and very powerful digital correlators to look for the characteristic 21- centimetre wavelength signal of Cosmic Hydrogen. With it Morgan and his Australian colleagues surveyed two thirds of the sky and found over 5,000 such sources among which they hoped to find Dark Galaxies.[See Written in the Stars quartet of novels under ‘My Books’ Category]
The Dish has a romantic background. It was built by Taffy Bowen who, together with Hanbury-Brown, devised the night-fighter radar system which put an end to the Nazi blitzes in 1942. Starting at Bawdsey Manor in 1936 they devised means to cram radar systems into aircraft — which was fiendishly difficult to do in those days when radar waves were 10 metres long. But somehow, supported by Air Marshall Dowding, the head of RAF Fighter Command, they eventually did so.
In 1941 Bowen was sent to the US with his notorious ‘Suitcase Full of Secrets’ to teach the Americans how to build effective radars [See my book ‘History of the Brits‘ for that story ]. Later Bowen came to Sydney to direct the CSIRO Radiophysics Lab and the grateful Americans gave him half the money to build the Parkes dish which was completed in 1961. In 1962 Cyril Hazard from the University of Sydney used it to locate the first Quasar when the radio source 3C-273 passed behind the Moon. The disappearance and re-appearance of the radio-signal enabled Hazard to get a very precise position for it — which corresponded to that of a moderately bright star. An optical spectrum of that star showed it to have a high redshift and so to be an enormous distance away. The first Quasar Stellar Radio Source, or ‘Quasar’ had been discovered — starting off a whole new branch of Astrophysics — leading eventually to the discovery that they are Super Massive Black Holes.
Hanbury-Brown — after whom the term “Boffin” was coined, also made his name later as an astronomer in Australia. He it was who completed the night-fighter radar system which did for the Blitz and saved Britain [He features extensively in my Second World War scientific novel ‘Strangle‘ described in ‘My Books’ Category] .
The main weakness of radio telescopes is the non-existence of a ‘radio-camera’ which can look in more than one direction at once. The big box you can see at the focus was the first successful attempt at one. It has got 26 receivers looking in 13 adjacent but different directions at once — which allowed us to survey two thirds of the entire sky for Hydrogen gas in deep space — in the hope of locating Hidden Galaxies (see our Post ‘Hidden Galaxies‘). Unfortunately we then totally cocked things up by mis-identifying all the 5000 such sources we found with conspicuous optical galaxies , which is all too easy to do when galaxies are so highly clustered together in Space. Actually many of the Parkes sources are indeed dim or dark galaxies or gas clouds. Astronomy is hard….but very exciting!
Tags: galaxies, hidden galaxies, History of the Brits, my books, strangle, telescopes
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