William Bradfield

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William Ashley Bradfield (born June 20, 1927 in Levin , New Zealand , † June 9, 2014 ) was a New Zealand astronomer. He was considered one of the world's most famous and successful comet discoverers.

Origin, family and job

Bradfield grew up on a dairy farm in New Zealand. After graduating as an engineer for mechanical engineering at the University of New Zealand in 1951 he went to Australia , where he worked for the Department of Defense in the development of solid rocket motors for studying the upper atmosphere worked. After ten years as head of the research department for rocket propulsion technology , he retired in 1986.

He first lived in Dernancourt, a suburb of Adelaide in South Australia . Because of his extraordinary ability to search for comets, he was nicknamed "The Wizard of Dernancourt" . He was married and had three daughters. Since 1995 he lived in Yankalilla south of Adelaide.

Activity as an amateur astronomer

Bradfield was an amateur astronomer , not a professional . Although he took an interest in astronomy at his father's farm in New Zealand at the age of 13, his interest in comets didn't develop until 1970 when he was 43. At the beginning of 1970 he had observed the bright comet C / 1969 Y1 (Bennett) , which made a great impression on him. This comet was discovered by an amateur astronomer in South Africa . Bradfield was a member of the Astronomical Society of South Australia , and in August of the same year he bought from another member a homemade telescope, one mm 150 - f / 5.5 - Refractor for 60 Australian dollars , and was determined to discover a comet itself . He began on January 1, 1971 and spent 260 hours of observation time until his name first appeared in the professional world with the discovery of the relatively bright comet with the designation C / 1972 E1 (Bradfield) . This spurred him to keep looking to prove to himself and others that his first discovery was more than just a stroke of luck. On March 23, 2004, at the age of 76, he discovered his 18th tail star, comet C / 2004 F4 (Bradfield) .

Bradfield was the most successful all- visual comet explorer of his time. All of the comets he found bear his name alone; he did not have to "share" a name with a second, independent explorer.

William Bradfield followed the words of the comet discoverer LC Peltier , who said: "To find a comet, you always have to search." To be able to conduct his search in a dark environment, Bradfield left his home in order to attach his portable telescope to one building lonely roadside. He drove to do this for about an hour, until he was 70 km from Adelaide. Since it is impossible to predict when a new comet will be found, he undertook his search at every favorable opportunity, whenever the sky was clear, even in the cold winter months . On average, he observed 8 hours during each lunar cycle ; H. about 100 hours a year , he systematically searched the sky up to 90 ° elongation from the sun . In his early years as a comet finder, he searched for 200 hours a year.

When he set off from home on his comet search, he had the choice between nine different observation locations (three only for observations in the evening after sunset , three only for observations in the morning before sunrise , and three for morning or evening). This enabled him to act very flexibly in order to avoid unfavorable weather conditions or to change location within 2 hours. To do this, he informed himself in advance about the weather forecasts in the media, but he also observed the movements and shapes of the clouds himself .

As there is fierce competition among comet seekers, he developed special strategies and techniques. In order to have an advantage over the very active Japanese comet seekers, he first searched the areas of the sky that would also have been the search area of ​​the Japanese in the northern hemisphere had they not been prevented by the weather conditions. To search the sky, he moved his telescope as effectively as possible. To do this, he built a special height-adjustable azimuthal mount for his telescope, which made the search easier for him.

As soon as he discovered a comet, he reported it to the International Astronomical Union . If the sighting is confirmed by other observers, the comet is officially recognized and after (or) discoverer (s) named .

Comet discoveries

  1. C / 1972 E1 , discovered March 12, 1972
  2. C / 1974 C1 , discovered February 12, 1974
  3. C / 1975 E1 , discovered March 12, 1975
  4. C / 1975 V2 , discovered November 11, 1975
  5. C / 1976 D1 , discovered February 19, 1976
  6. C / 1976 E1 , discovered March 3, 1976
  7. C / 1978 C1 , discovered February 4, 1978
  8. C / 1978 T3 , discovered October 10, 1978
  9. C / 1979 M1 , discovered June 24, 1979
  10. C / 1979 Y1 , discovered December 24, 1979
  11. C / 1980 Y1 , discovered December 17, 1980
  12. C / 1984 A1 , discovered January 7, 1984
  13. C / 1987 P1 , discovered August 11, 1987
  14. C / 1989 A3 , discovered January 6, 1989
  15. C / 1992 B1 , discovered January 31, 1992
  16. C / 1992 J2 , discovered May 3, 1992
  17. C / 1995 Q1 , discovered August 17, 1995
  18. C / 2004 F4 , discovered March 23, 2004

Almost all of Bradfield's discoveries were initially only weak spots, mostly only from 9th to 10th magnitude . Stars and comets of this brightness can hardly be seen even in large binoculars . The most suitable telescopes for this are bright “ comet seekers ” with a short focal length and low magnification . Bradfield used in almost all cases a 150-mm - f / 5.5 - refractor , some times referred to a 250-mm - f / 5.6 - reflector or a 7 × 35mm binoculars.

Awards

  • 1981 - Berenice Page Medal from the Astronomical Society of Australia . For the discovery of 11 comets by that time.
  • 1989 - Honorary Life Member of the Astronomical Society of South Australia . In recognition of his comet discoveries, especially his 13th discovery in September 1987, which made him the most successful comet hunter of the century .
  • 1989 - Member of the Order of Australia . In recognition of his services to astronomy.
  • 2000 - The Astronomical Society of South Australia donates the Bill Bradfield Astronomy Award . The prize is awarded annually to amateur astronomers from South Australia in recognition of a special contribution to astronomy, whether through astronomical discovery, research or observation over a period of time.
  • 2003 - An asteroid discovered in 1980 in the main belt is given the official designation (3430) Bradfield after William A. Bradfield.
  • 2004 - Edgar Wilson Award from the Smithsonian Astrophysical Observatory (with V. Tabur). The award is given to amateur astronomers who have discovered one or more new comets in the past 12 months using privately owned amateur instruments.

Web link

Individual evidence

  1. ^ W. Liller: The Cambridge Guide to Astronomical Discovery , Cambridge University Press, ISBN 978-0521126052 , 2010, pp. 118-119.
  2. ↑ B. Haran: An eye on the southern sky. In: BBC News. May 4, 2004, accessed May 14, 2014 (with photo by W. Bradfield).
  3. ↑ Septuagenarian 'Wizard' Finds Bright Comet. (No longer available online.) Archived from the original on October 30, 2013 ; accessed on May 14, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / home.earthlink.net
  4. ↑ a b W. A. ​​Bradfield: Untitled Remarks . In: W. Liller: The Cambridge Guide to Astronomical Discovery , Cambridge University Press, ISBN 978-0521126052 , 2010, pp. 58-61.
  5. ^ RW Sinnott: Bradfield's 18th Comet. In: Sky and Telescope. May 24, 2004, accessed May 14, 2014 .
  6. ^ A b Astronomical Society of South Australia: Comets Discovered from South Australia. Retrieved May 14, 2014 .
  7. ^ The Astronomical Society of Australia, Inc .: The Berenice and Arthur Page Medal. Retrieved December 2, 2015 .
  8. ^ Astronomical Society of South Australia - A Brief History. Retrieved May 14, 2014 .
  9. ^ Australian Government - It's an Honor. Retrieved May 14, 2014 .
  10. ^ Astronomical Society of South Australia Awards. Retrieved May 14, 2014 .
  11. ^ IAU Minor Planet Center. Retrieved May 14, 2014 .
  12. ^ EL Aguirre: 2004 Comet Award Winners. In: Sky and Telescope. July 19, 2004, accessed May 14, 2014 (with photo by W. Bradfield).
personal data
SURNAME Bradfield, William
ALTERNATIVE NAMES Bradfield, William A.
BRIEF DESCRIPTION New Zealand astronomer and comet discoverer
DATE OF BIRTH June 20, 1927
PLACE OF BIRTH Levin , New Zealand
DATE OF DEATH June 9, 2014