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

A. Nakamura image of 50P exposed on 1999 October 20
Copyright © 1999 by A. Nakamura (Kuma Kogen Astronomical Observatory, Japan)

This CCD image was taken on 1999 October 20.77 UT, using a 0.60-m f/6 Ritchey-Chretien telescope.


     This comet was found by Sylvain Arend (Royal Observatory, Uccle, Belgium) on plates exposed on 1951 October 4 with a 40-cm Zeiss double astrograph for a routine minor planet survey. The comet was then described as about magnitude 14, and exhibited a conspicuous nucleus within a coma 14 arc seconds across. Shortly after the discovery announcement, a prediscovery image was found on a plate exposed at Yerkes Observatory on October 1.

Historical Highlights

  • The 1951 apparition remains the brightest observed for this comet because of the maximum brightness of magnitude 14. The orbital period of 7.8 years steadily made each succeeding apparition less favorable and an approach to within 0.64 AU of Jupiter in 1969 increased the period to 8.0 years, which locked the comet's maximum magnitude at about 15.
  • The comet's maximum brightness would not have exceeded 17 in 1959 had it not been for an outburst shortly before November 25 that took the brightness to magnitude 15.5.
  • Long-term studies of the comet's motion by Brian G. Marsden have revealed the orbit has been relatively undisturbed by Jupiter since at least 1725.
  • Apparition of 1999: K. Muraoka took positions from the years spanning 1951-1991 and predicted the comet would next return to perihelion on 1999 August 3.77.
  • Additional Images

    M. Jäger image of 50p exposed on 1999 October 16
    Copyright © 1999 by Michael Jäger (Austria)

    The photograph is an 11-minute exposure taken on 1999 October 16 UT, using a 25-cm Schmidt camera and Kodak TP6415 film. The comet was estimated as magnitude 15.0. [The image was cropped by the webmaster.]