Copyright © 1997 by Akimasa Nakamura (Kuma Kogen Astronomical Observatory, Japan)
This CCD image was taken on 1997 December 4.74, using a 0.60-m f/6 Ritchey-Chretien telescope.
Caroline S. Shoemaker, Eugene M. Shoemaker, and David H. Levy (Palomar Observatory) reported discovering this comet on images obtained with a 0.46-m Schmidt telescope on 1991 February 7.34 and February 8.26. The magnitude was estimated as 16.5 and the comet was described as "moderately diffuse, with hint of a tail to the northwest."
Following the acquisition of images up through 1991 February 11, Brian G. Marsden (Central Bureau for Astronomical Telegrams) computed the first orbit which inicated the comet was moving in a short-period orbit. This preliminary orbit indicated a perihelion date of 1991 February 26 and an orbital period of 7.26 years. The comet was ignored in the weeks that followed, and new observations did not become available until April. At that time Marsden was able to revise the orbit, which indicated a perihelion date of 1990 December 26.8 and a period of 7.25 years. Final orbits following the acquisition of additional observations indicated a perihelion date of December 12.8.
As noted above, the comet was largely ignored during its discovery apparition. Since it was already passed perihelion, the magnitude faded from 16.5 at discovery to 17.5 in mid-April. The comet was last seen on May 5, when the magnitude had dropped to 19.
S. Nakano provided a prediction for the 1998 return, but, before searches could be made for a recovery, word came that A. Maury, M. Lundstrom, and G. Hahn had accidentally recovered the comet on minor planet survey plates obtained with the 0.9-m Schmidt telescope at Caussols on 1996 October 17.99. The comet was described as diffuse, with a magnitude of 19.3. The position indicated Nakano's prediction required a correction of -0.1 day. Revised computations indicated the comet would arrive at perihelion on 1998 March 4.9. With a perihelion distance of 2.82 AU, it was not expected to become brighter than magnitude 16, although this was based on the incomplete coverage of the 1991 apparition. During late January of 1998, some observers were estimating a brightness greater than 15.