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99P/Kowal 1

Past, Present, and Future Orbits by Kazuo Kinoshita


     Charles T. Kowal (Palomar Observatory, California, USA) discovered this comet on a photographic plate exposed with the 122-cm Schmidt telescope on 1977 April 24.39. He estimated the magnitude as 16 to 17, and described the comet as diffuse with some condensation and a tail extending 2 arc minutes toward the northeast. It was then in Virgo. Images also appeared on plates exposed with the same telescope on the 25th and 26th.

Historical Highlights

  • The comet was already passed perihelion when found in 1977 and remained visible until June 17, when near magnitude 19.
  • Using observations obtained from April 24 through May 19, B. G. Marsden computed an elliptical orbit with a period of 18.6 years. As further observations were obtained the period was revised. During 1979 Marsden gave the period as 15.11 years and said the short observational arc brought about an uncertainty of about 2 weeks.
  • S. Nakano provided a prediction for the expected 1992 return. He determined the perihelion date as 1992 June 12.88 and gave the orbital period as 15.08 years. J. V. Scotti, using the Spacewatch telescope at Kitt Peak, recovered the comet on 1991 February 21.41. Then at magnitude 18.4, the precise position indicated an actual perihelion date of 1992 March 10.35 and an orbital period of 15.02 years. The comet was then exhibiting a coma 15 arc seconds across and a tail extending 29 arc seconds in PA 297°. The comet was followed until 1992 April 25.
  • Apparition of 2007: Observations of this comet spanned the period of 2004 October 21 to 2008 July 9. The comet was more or less observed around opposition each year it was observed, attaining a maximum magnitude of 18.0-18.5 early in 2005, 17.0 early in 2006, 16.5 around mid-2007, and 17.5 around mid-2008.
  • cometography.com