William Ashley Bradfield (20 June 1927 – 9 June 2014) was a New Zealand-born Australian amateur astronomer, notable as a prolific amateur discoverer of

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...

s. He discovered 18 comets, all of which bear his name as the sole discoverer. His astronomical achievements were summed up by Brian G. Marsden, director emeritus of the

IAU The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...

's Central Bureau for Astronomical Telegrams: "To discover 18 comets visually is an extraordinary accomplishment in any era, but to do so now is truly remarkable, and I think we can be pretty sure nobody will be able to do it again. And it's all the more astounding that in no case did he have to share a discovery with some other independent discoverer. More than any other recipient, Bill Bradfield outstandingly deserves the Edgar Wilson Award."

Biography

Bradfield was born in Levin, New Zealand on 20 June 1927. He grew up on a dairy farm, where his interests in rocketry and astronomy first developed, and when he was 15 he got his first small telescope. He attended the

University of New Zealand The University of New Zealand was New Zealand's sole degree-granting university from 1874 to 1961. It was a collegiate university embracing several constituent institutions at various locations around New Zealand. After it was dissolved in 196 ...

, where he graduated with a bachelor's degree in Mechanical Engineering. He spent 2 years in England doing a rocket propulsion residency and then in 1953 he moved to Australia, taking up residence in Adelaide, where he worked for the Australian Department of Defence as a rocket propulsion engineer and research scientist until he retired in 1986. This was also where he met Eileen; they were married in 1957, and they went on to have three daughters. Bradfield joined the

Astronomical Society of South Australia The Astronomical Society of South Australia (ASSA) was founded in 1892 and is the oldest society of its kind in Australia. It is the only representative body for amateur astronomy in the state of South Australia. It holds regular general monthly me ...

(ASSA) in 1970 which fueled his interest, and he started hunting for comets in 1971, using a second-hand telescope which he bought from another ASSA member. Just over a year and 260 hours of searching later, he was rewarded with finding Comet Bradfield (C/1972 E1). Six comets followed in his first six years, and in 1987 the discovery of his 13th comet made him the most prolific comet-hunter of the 20th century. Eventually his count built to 18 comets after 3500 hours of searching, with the 18th and final comet discovery coming on 23 March 2004 when he was 76 years old. When Bradfield discovered a comet and communicated it to the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

(IAU), it kicked off worldwide action. Within 14 hours of reporting his 17th comet in 1995, it had been observed by more than 20 observers, including the

European Southern Observatory The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental organization, intergovernmental research organisation made up of 16 mem ...

(ESO) 1-meter Schmidt telescope at La Silla, Chile. Bradfield

His discoveries were particularly notable because he worked alone to discover them, using old and home-made telescopic equipment. Apart from the 100-year-old lens and modern eyepieces, the remainder of his telescope was homemade, but perfectly suited for hunting comets. He did not use photographic or computerized detection equipment, relying instead on purely visual sweeping across the skies. Having joined the

(ASSA) in 1970, Bradfield served as its President from 1977 to 1979. In 1989 he was appointed an honorary Life Member, and he was inducted into the ASSA Hall of Fame in 2013. He died on 9 June 2014 after a long illness, at age 86.

Awards and honors

* Asteroid

3430 Bradfield 3430 Bradfield ( ''prov. designation'': ) is a stony Agnia asteroid from the central regions of the asteroid belt, approximately in diameter. It was discovered on 9 October 1980, by American astronomer Carolyn Shoemaker at the Palomar Observator ...

was named in his honour. * Bradfield received the Berenice and Arthur Page Medal from the Astronomical Society of Australia in 1981. * He was made a member of the

Order of Australia The Order of Australia is an honour that recognises Australian citizens and other persons for outstanding achievement and service. It was established on 14 February 1975 by Elizabeth II, Queen of Australia, on the advice of the Australian Gove ...

(AM) "in recognition of his service to astronomy" in 1989. * He was made an Honorary ''Life Member of the Astronomical Society of South Australia'' in 1989. * In 2000 the Astronomical Society of South Australia created the ''Bill Bradfield Astronomy Award'' in honour of his achievements, given to an amateur who displays exceeding accomplishment in a given year in the field of astronomy. * He was awarded the Edgar Wilson Award from the

Smithsonian Astrophysical Observatory The Smithsonian Astrophysical Observatory (SAO) is a research institute of the Smithsonian Institution, concentrating on astrophysical studies including galactic and extragalactic astronomy, cosmology, solar, earth and planetary sciences, the ...

(SAO) through the

's Central Bureau for Astronomical Telegrams (CBAT) in 2004. * In 2013 he was inducted into the ''ASSA Hall of Fame''.

List of discovered comets

Comet: Initial designation of the comet
Hours: Number of search hours for discovery
Date: Discovery date in UT
Mag: Total magnitude (brightness) of comet at discovery

References

{{DEFAULTSORT:Bradfield, William A. 1927 births 2014 deaths Discoverers of comets 20th-century New Zealand astronomers 20th-century Australian astronomers University of New Zealand alumni Members of the Order of Australia People from Levin, New Zealand 21st-century Australian astronomers Amateur astronomers New Zealand emigrants to Australia