Bill Bradfield world's top comet hunter with cobbled telescope from Astronomical Society of South Australia fellow
Bill Bradfield in his backyard at the Adelaide suburb of Dernancourt with the home-made-made secondhand telescope that he used to became the 20th's Century's world record comet hunter.
Bill Bradfield was inspired to become the world's top 20th Century comet hunter after joining the Astronomical Society of South Australia in 1970 and buying a home-made telescope from Ralph Sangster, another society member. He gained a world record by visually discovering 18 comets, all bearing his name as sole discoverer.
New Zealand-born Bradfield grew up on a dairy farm where he developed an interest in rocketry and astronomy and got his first small telescope at 15. Graduating from the University of New Zealand with a bachelor's degree in mechanical engineering, he spent two years in England on a rocket propulsion residency before moving to Adelaide in 1953 to worked for the Australian defence department as a rocket propulsion engineer and research scientist until he retired in 1986.
His occasional amateur astronomy became more ambitious in 1970 when Comet Bennett appeared in the predawn sky. Just over a year and 260 hours of searching later, he was rewarded with finding his first: Comet Bradfield (C/1972 E1). Six comets followed in his first six years.
Based in the Adelaide suburb of Dernancourt, Bradfield’s telescope, bought from Sangster, cobbled together from unfinished boards and spare parts.
But it was superbly suited for finding comets with a giant Dallmeyer camera lens, made a century earlier for portrait photography with an aperture of six inches. A war-surplus Erfle eyepiece provided 26x.
Bradfield used a sinusoidal template to slide over his large star charts and plot his own horizon at morning or evening twilight. By flipping the template, he could plot the horizon that same night for Japanese comet hunters – his fiercest competitors.
In 1987, Bradfield’s 13th comet made him the most prolific comet-hunter of the 20th century. When Bradfield discovered a comet and communicated it to the International Astronomical Union, it would be confirmed within hours by observers around the world. Bradfield’s count built to 18 comets after 3500 hours of searching, with the 18th and final comet discovery in 2004 when he was 76.
Bradfield was Astronomical Society of South Australia president 1977-79, a life member from 1989 and inducted into its hall of fame in 2013.
