G A R Y   W.   K R O N K ' S   C O M E T O G R A P H Y


Past, Present, and Future Orbits by Kazuo Kinoshita

H. Mikuz image of 22P exposed on 1996 June 7
Copyright © 1996 by Herman Mikuz (Crni Vrh Observatory, Slovenia)

This CCD image was taken on 1996 June 7.95 UT, with a 36-cm, f/6.8 Schmidt-Cassegrain telescope, V-filter and Wright CCD. Exposure time was 2 min.


     Discovered by August Kopff (Königstuhl Observatory, Heidelberg, Germany) on 1906 August 23.07. It was then estimated as about magnitude 11. An examination of previous plates of this region revealed a prediscovery image on a photographic plate exposed by Kopff on August 20.93.

Historical Highlights

  • Short-period nature was independently recognised by Ebell (Kiel), and Crawford and Champreux (Berkeley Astronomical Department, California) around mid-September 1906.
  • Comet missed at next return in 1912-1913 because it was unfavorably situated, but was recovered in 1919 less than three days from the predicted position. It has not been missed since.
  • After several returns where the maximum brightness failed to exceed 10.5, the 1945 return was exceptional with the maximum magnitude reaching 8.5. Credit for this brighter return goes to Jupiter for having altered the comet's orbit in the years between the returns of 1939 and 1945. The comet's perihelion distance was decreased from 1.68 AU to 1.50 AU, while the orbital period dropped from 6.54 to 6.18 years.
  • The 1951 return was unique. When recovered on April 12 it was three magnitudes fainter than predicted, and remained below expectations for the next few months. However, around the time of perihelion in late October, the comet suddenly brightened two magnitudes to a brightness of 10.5. It was still near 11.5 when last detected on November 29.
  • The comet passed very close to Jupiter in 1954. The perturbations increased the perihelion distance to 1.52 AU and increased the orbital period to 6.31 years. Although these changes were relatively minor, the remaining angular portions of the comet's orbit underwent rather drastic changes. Nevertheless, calculations by Kepinski allowed the comet to be recovered only 3 arc minutes from its predicted position on 1958 June 25.
  • For the 1996 apparition, the comet was recovered on November 30.5, 1994, by C. W. Hergenrother (Lunar and Planetary Laboratory, Arizona, USA) on frames obtained by S. M. Larson with the 1.5-m reflector at the Catalina Station. The comet was then stellar with a magnitude of 22.8. This was the 14th appearance of this periodic comet, and was particularly favorable with the comet passing closest to the sun on July 2 (1.5796 AU) and closest to Earth on July 8 (0.5651 AU). Subsequently the maximum magnitude reached 7 in early July.
  • Close approaches to planets: The comet experienced six close approaches to Earth and two close approaches to Jupiter during the 20th century. It will make three close approaches to Earth and two close approaches to Jupiter during the first half of the 21st century. (From the orbital work of Kazuo Kinoshita)
    • 0.70 AU from Earth on 1919 July 10
    • 0.86 AU from Earth on 1932 June 7
    • 0.57 AU from Jupiter on 1943 March 8
      • decreased perihelion distance from 1.68 AU to 1.50 AU
      • decreased orbital period from 6.54 to 6.18 years
    • 0.69 AU from Earth on 1945 June 10
    • 0.17 AU from Jupiter on 1954 March 30
      • increased perihelion distance from 1.49 AU to 1.52 AU
      • increased orbital period from 6.18 to 6.31 years
    • 0.83 AU from Earth on 1964 August 11
    • 0.72 AU from Earth on 1983 June 11
    • 0.57 AU from Earth on 1996 July 8
    • 0.77 AU from Earth on 2009 August 4
    • 0.44 AU from Jupiter on 2026 April 26
      • decreased perihelion distance from 1.55 AU to 1.32 AU
      • decreased orbital period from 6.38 to 5.87 years
    • 0.35 AU from Earth on 2028 July 13
    • 0.92 AU from Earth on 2034 August 31
    • 0.67 AU from Jupiter on 2038 March 3
      • decreased perihelion distance from 1.32 AU to 1.19 AU
      • decreased orbital period from 5.87 to 5.59 years

    Additional Images

    Masayuki Suzuki image of 22P exposed on 1996 July 13
    Copyright © 1996 by Masayuki Suzuki (Japan)

    This image was taken on 1996 July 13, using a 0.20-m f/10 LX200 telescope and a CCD camera. The image is a 30-second exposure.