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Past, Present, and Future Orbits by Kazuo Kinoshita

DSS2 image of 115p exposed on 1985 September 7
Copyright © 1993-2000 by the Anglo-Australian Observatory Board

In the course of the Science and Engineering Research Council (SERC) Southern Equatorial R Survey, the 122-cm UK Schmidt at Siding Springs Observatory (New South Wales, Australia) accidently photographed this comet on 1985 September 7.52. The exposure was 75 minutes in length. The comet trailed during the exposure. This image was obtained through SkyMorph at the Goddard Space Flight Center.


     Alain Maury discovered this comet on photographic exposures obtained with the 1.2-m Schmidt telescope at Palomar Observatory (California, USA) by J. Schombert on 1985 August 16 and 17. He described it as diffuse, with a condensation and a short tail. The total magnitude was given as 16.

Historical Highlights

  • With the comet first being announced on 1985 September 6, or about three weeks after the plates were obtained, confirmation came quickly from other observers at Palomar Observatory. S. Singer-Brewster, D. Schneeberger, and M. Gallup found the 15th-magnitude trail of the comet on a plate exposed with the 0.46-m Schmidt telescope on August 20. Meanwhile, R. Windhorst found a magnitude 16 image on a plate exposed with the 1.2-m Schmidt telescope on August 23. In reponse to the initial announcement of the comet, several confirmations were announced on September 13. These came from J. Gibson (Palomar Observatory), who used the 1.5-m reflector and a CCD to detect the comet on September 7 and 8, and from G. Schwartz and C.-Y. Shao (Oak Ridge Observatory), who detected the comet on September 12. The comet was followed until 1986 January 7, when it was detected at Steward Observatory (Arizona, USA).
  • Using the photographic images obtained from August 16 to 23, Brian G. Marsden (Central Bureau for Astronomical Telegrams) computed an elliptical orbit which was first published on September 9. The orbit indicated a perihelion date of 1985 June 13, a perihelion distance of 2.02 AU, and an orbital period of 8.56 years. Following the acquisition of the September images from Palomar and Oak Ridge, Marsden redetermined the orbit and derived a perihelion date of June 8.6, a perihelion distance of 2.014 AU, and an orbital period of 8.835 years. The orbit computed after the observations had been obtained into January indicated only slight corrections.
  • James V. Scotti (Steward Observatory, Arizona, USA) detected the comet with a 0.91-m telescope on 1994 May 3 and 4. Magnitudes were given as 17.7 to 17.9 and the comet was said to be exhibiting a coma 9 arc seconds across and a tail 0.25 arc minute long that was extending westward. The precise positions indicated the prediction required a correction of -0.52 day. The comet was kept under observation until 1994 October 25, when it was seen at Kuma Kogen Observatory in Japan.
  • The comet was detected near its aphelion by astronomers at Mauna Kea (Hawaii, USA) on 1997 December 30.53.
  • The comet was next predicted to pass perihelion on 2002 December 23. It was formally recovered on 2002 May 12 at Kuma Kogen Observatory.
  • cometography.com