Bill Bradfield AM

An amateur astronomer who discovered 18 new comets

Proof that you don’t always need the latest equipment to achieve extraordinary things, South Australian William ‘Bill’ Bradfield became one of the greatest astronomical discoverers of the twentieth century. Using mostly backyard equipment, this amateur astronomer discovered 18 new comets and has been called the greatest comet hunter of all time.

Bradfield was born on 20 June 1927 and grew up on a dairy farm in New Zealand. At age 15 he already had a love of the night sky when he got his first telescope.

After studying Mechanical Engineering at the University of New Zealand, Bradfield migrated to Australia, aged 25, as a rocket scientist. He worked for the Australian Department of Defence in Adelaide and remained in that job until he retired in 1986.

In 1970, a brilliant comet called Bennett lit up the night skies, and Bradfield, looking skyward, was hooked. He joined the Astronomical Society of South Australia (ASSA) and bought a second-hand telescope from another member for $60. Featuring a 100-year-old lens and held together in places with bits of string, a cobbled together wooden construction and juice bottle top, it wasn’t expected to lead to new discoveries.

But after patiently scanning the skies night after night for 260 hours, Bradfield found his first comet (called Comet Bradfield). Rather than using computer software to scan the skies, he just methodically swept his telescope over the stars, looking for things that moved. “When you come across something that you don’t remember being in that spot, the excitement starts from that moment. It’s a comet!” he said.

Over the next six years this mild-mannered man discovered five more comets. Bradfield found a total of 14 with his old telescope until he upgraded to a newer model, which also benefitted from his home handywork. After spending a total of 3500 hours searching, Bradfield found his 18th and final comet in 2004 when he was 76 years old.

Bill Bradfield served as ASSA president from 1977 to 1979. In 1989 he was made a Member of the Order of Australia in recognition of his service to astronomy and was inducted into the ASSA Hall of Fame in 2013. He died in 2014 at the age of 86.

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