Comet Bradfield 1987 P1

Comet Bradfield 1987 P1

William Ashley Bradfield (20 June 1927 – 9 June 2014) was a New Zealand-born Australian amateur astronomer, notable as a prolific amateur discoverer of comets. He gained a world record by discovering 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'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.

The comet was discovered on the evening of August 11, 1987 by William A. Bradfield in Australia with a 150 mm - f / 5.5 - Refractor. It was his 13th comet discovery, about 3 ½ years after his last. He had been searching for a total of 307 hours for comets during this period.

At the time of its discovery, the comet moved in the constellation Water Serpent when it was still 1.57 AU from Earth and 1.72 AU from the Sun. Despite his already relatively high brightness of 10 mag, he apparently was not discovered earlier, because at the time of his opposition in mid-May of the year he was at a brightness of 12 mag in the star-rich areas of the southern Milky Way . As of October, the comet was also in the northern hemispherevisible. Its brightness increased rapidly, it was still about 7 mag on the 10th of October, by the end of the month the comet became visible to the naked eye and reached about 5 mag in November 1987. It was thus the brightest comet since the return of the Halley's comet in 1986. After that he became weaker again and could no longer be seen with the naked eye from mid-December. He had almost 90 ° its largest turn of the year elongation from the sun reached. His last observation was carried out on 13 April 1988.

For a short time the comet showed besides a nearly 2 ° long plasma tail also a distinct counter-tail.