September General Meeting Report
William (Bill) Bradfield, world renowned comet hunter from South Australia
in the Lecture Theatre S5, Building 24 at Monash University
A hush falls over the audience as the tall, white-bearded and well-dressed gentleman stepped up to the podium. So this is Bill Bradfield. The legendary, world renowned comet hunter from Yankalilla, South Australia; recipient of the 2004 Edgar Wilson Award from the International Astronomical Union, the society which names, numbers and registers new comets, for his discovery of comet C/2004 F4. With 18 comet discoveries to his name, 6 more than any other living amateur astronomer, this 76-year-old father of three and former government rocket propulsion scientist, who made his first discovery from a backyard in Dernancourt in 1972 and was awarded the Order of Australia in 1989 for his service to Astronomy, this living legend is going to talk to us tonight.
Bill starts to talk, hesitantly at first; as he speaks of the perils of working alone, stumbling around in the dark late at night or early in the morning, often on strange sites with kangaroos, rabbits and snakes as the only companions. He speaks of his encounters with suspicious farmers and frightened lovers as he drags his handmade, $300 Newtonian reflector telescope onto his chosen viewing site for the night. "It may be rough and ready," he says about his equipment, "but you don't need a chrome plated telescope to discover a comet". Built in 1984 the telescope actually includes a couple of house-bricks to help with the counter-balance. Mr. Bradfield spends about two to three hours a session stargazing (after this your eyes get tired and you lose concentration) at two spots usually near the Mt Lofty Ranges and also from his backyard. For searching he prefers the country sites, there is less interference from lights and passing traffic. And he obviously choses nights free from what he calls the two 'curses of astronomers' – bright moonlight and cloud cover.
Bill’s determination to succeed in the amateur field of his choosing in 1971 became obvious with his first discovery: it took 1700 hours of viewing time! By 1995 though he had clocked up 17 new comets, concentrating as he says “on that slice of the sky not accessible to the searchers based in the Northern Hemisphere who can't see what I call the 'deep south”. But with the advent of automated computer technology, like the Near Earth Asteroid Tracking (Neat) system and the Lincoln Near Earth Asteroid Research (Linear) project, pickings were getting slim and it took 9 long years to clock up number 18. He spotted the object with his 10-inch telescope in the constellation Cetus low in the western evening sky from a roadside lookout, 6km south of Yankalilla, on March 23, at 7.45pm. After sighting it he sketched the nearby star field pattern and went home to match it with his astronomy charts to confirm the "dirty snowball" had not already been discovered, before reporting it. In reply to a question from the audience whether he usually follows up on composition and orbit of his “dirty snowball” discoveries, he confesses “I prefer to spend my time looking for another one. There are lots of people around that like to trace the development of these ‘ghosts of the Solar System’, work out their orbits and note whether they're getting bigger or are developing a tail". The acclaim of the scientific world for his uncanny knack for visually discovering comets he modestly puts down to "having a good eye. But”, he admits, “I was really excited with this last one for, after going for 9 years without a discovery it proved I still do have it”. The figures speak for themselves: eighteen comets over a 32-year time span comes out to an average of one new discovery about every 21 months.
Zum Sehen geboren, zum Schauen bestellt ... begins a well-known poem by Goethe, “born to see and endowed with the desire to look...” highlighting that special ‘talent of seeing’ only a few people are gifted with. A talent to comprehend vision beyond our ordinary ability to look and see what the eye focuses on. Call it a talent, a gift, determination, photographic memory, averted vision or just “having a good eye”, when it comes together as it does in the person of Bill Bradfield and his search for those ephemerous ghosts of the Solar system it makes for a very successful combination. The vote of appreciation is given by Barry Adcock and unanimously endorsed.
Comet 2004 F4 - Bradfield, photograph by Michael Jäger and Gerald Rhemann. It reached perihelion (its closest approach to the Sun) on April 17, when it was just 0.169 astronomical unit (15.7 million miles, or 25.2 million kilometers) from the solar system's central star. This is well inside the orbit of the planet Mercury.