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

J. Scotti image of 133P exposed on 1996 September 21
Copyright © 1996 by James V. Scotti

This image was obtained on 1996 September 21 with the 0.91-m Spacewatch telescope. The width is 9 arc minutes, with North at top and West at right. (The image was reversed by the webmaster in order to better represent the appearance of the comet.)


     On 1996 August 7 Eric W. Elst announced his discovery of a comet on a plate exposed by Guido Pizarro with the European Southern Observatory 1.0-meter telescope on 1996 July 14. The total magnitude was determined as 18.3 and a narrow tail extended about 1 arc minute toward the southwestern quadrant. Additional images were found on plates exposed on July 16.
     Prediscovery images were found on plates exposed in 1979 and 1985. During the first year the comet had been photographed at Siding Spring and Palomar observatories on 1979 July 24 and 25. It was estimated as magnitude 19.5 and was completely stellar in appearance. It had been reported at the time and was subsequently classed as a minor planet and was designated 1979 OW7. Computations revealed the comet had passed perihelion on 1979 July 13. R. H. McNaught (Anglo-Australian Observatory) subsequently found a trailed image of the comet on a 75-minute exposure obtained with the U.K. Schmidt on 1985 Sept. 15 by M. R. S. Hawkins. It was again completely asteroidal and about magnitude 19.

Historical Highlights

  • Brian G. Marsden (Central Bureau for Astronomical Telegrams) computed the first orbit and immediately recognized the comet was moving in a short-period orbit. What was unexpected was that the orbit was very similar to that found for a main belt minor planet, so that it always remained between the orbits of Mars and Jupiter. Marsden's initial orbit indicated a perihelion date of 1996 April 16.0, a perihelion distance of 2.618 AU, and an orbital period of 5.605 years.
  • Additional Images

    J. Ticha, M. Tichy and Z. Moravec image of 133P exposed on 1996 August 20
    Copyright © 1996 by J. Ticha, M. Tichy and Z. Moravec (Klet' Observatory, Czech Republic)

    The image of comet Elst-Pizarro was taken on 1996 August 20.893 UT with 0.57-m f/5.2 reflector + CCD camera SBIG ST-8 of Klet' Observatory and is 120 seconds exposure. The field of view is 16 to 10 arc minutes with north to the top and west to the right. (The webmaster has reversed the image to better represent the view of the comet.)