185P/Petriew
185P/Petriew is a periodic comet with an orbital period of 5.5 years. It was discovered by amateur astronomer Vance Avery Petriew on 18 August 2001.
Observational history
Vance Avery Petriew discovered the comet visually with a 0.51-m reflector telescope during a star party in Cypress Hills, Canada, on 18 August 2001, while he was searching for the Crab Nebula. He became the third Canadian amateur astronomer to discover a comet. Petriew estimated that the comet had an apparent magnitude of 11, a coma about three arcminutes across and no tail. For the discovery V. A. Petriew was awarded the Edgar Wilson Award in 2002. The comet was also observed by other participants of the party. Alan Hale imaged the comet with a CCD on 19 August and estimated the comet had an apparent magnitude of about 13.The comet continued to brighten during August, reaching magnitude 10. The coma diameter was reported to be 2 to 4 arcminutes. No tail was observed visually, but CCD imaging revealed the presence of a narrow tail. The comet was observed spectographically in September 2001 and was found to have normal production rates of diatomic carbon and water for a Halley-type comet. The comet was quickly found to be periodic, with a period of about 5.5 years. The comet had approached Jupiter to a distance of on 3 July 1982 and as a result its perihelion distance was decreased from 1.37 AU to 1.00 AU.
The comet was recovered on 11 January 2007 by F. Fratev, E. Mihaylova, and A. Kirchev using a 0.25m reflector telescope at Zvezdno Obshtestvo Observatory in Plana, Bulgaria. The comet then had an apparent magnitude of 16.1 and a diffuse coma 0.2 arcminutes across. After recovery, the comet was given the number 185P.