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89P/Russell 2

Past, Present, and Future Orbits by Kazuo Kinoshita


K. S. Russell (Siding Spring Observatory, New South Wales, Australia) discovered this comet on a 90-minute exposure obtained by J. Barrow with the 122-cm UK Schmidt Telescope on 1980 September 28.40. Russell said the comet was "sharply defined, with an extended patch surrounding it." The magnitude was estimated as 17. Russell confirmed the find when a plate was exposed by A. Savage on October 2.42. After preliminary orbital computations had been published, M. P. Candy computed an ephemeris for the period prior to discovery. Russell then identified a trailed image of the comet on a plate exposed by Savage on August 9.60. The image at right is the prediscovery image of 89P from August 9. Russell estimated the magnitude as 16.

The prediscovery image of 89P exposed on 1980 August 9

Historical Highlights

  • The first orbit was calculated by B. G. Marsden and revealed the comet was moving in an elliptical orbit. Published on 1980 October 8, it gave the perihelion date as 1980 May 12.81 and the period as 7.19 years. Following the finding of the August 9 prediscovery image, Marsden published a revised orbit on October 10. The perihelion date was given as May 19.55 and the period was 7.12 years. Multiple apparition orbits have revealed a perihelion date of May 19.02 and a period of 7.12 years.
  • The comet was only observed for a few more days following the confirmation photograph. Astronomers at Siding Spring Observatory photographed the comet on October 3 and 6, while J. Johnston (Perth Observatory, Bickley, Western Australia, Australia) obtained a 72-minute exposure with the 33-cm astrograph on October 6. The comet was last detected on October 7.53, when P. Jekabsons (Perth Observatory) detected it on a 144-minute exposure obtained with the 33-cm astrograph.
  • cometography.com