Copyright © 1993-2000 by the California Institute of Technology
DISCOVERY IMAGE: In the course of the Second Palomar Observatory Sky Survey, the 48-inch Oschin Schmidt Telescope at Palomar Observatory (California, USA) accidently photographed this comet on 1990 September 15. The comet trailed during the exposure of the Kodak IIIaF (red) plate. This image was obtained through SkyMorph at the Goddard Space Flight Center.
During the course of the second Palomar Sky Survey, Jean Mueller found this comet on a plate obtained on 1990 September 15.35. The image was obtained with the 1.2-m Oschin Schmidt Telescope. Mueller estimated the magnitude as 17 and said a tail was visible to the south-southwest.
Following the acquisition of images up through 1990 September 20, Daniel W. E. Green (Central Bureau for Astronomical Telegrams) computed the first parabolic orbit. It indicated a perihelion date of 1991 February 24.85, and a perihelion distance of 1.633 AU. He added that it was possible this was a short-period comet. By the end of September, enough precise positions had been made by various observatories to enable Green to confirm the comet's short-period motion. His new orbit indicated a perihelion date of 1990 November 8.8, a perihelion distance of 2.078 AU, and an orbital period of 6.42 years. Ultimately, the period proved to be just over 7 years.
The comet brightened to about 16 by late September and early October as it approached both the sun and Earth, but slowly faded thereafter. It was last detected on 1991 February 9.
The comet was independently recovered by two Japanese astronomers during 1997. A. Sugie (Dynic Astronomical Observatory) used a 0.60-m f/4.0 reflector and a CCD camera to image the comet on June 29.75, while A. Nakamura (Kuma Kogen) used a 0.60-m f/6.0 Ritchey-Chretien and a CCD camera to image the comet on July 5.77. Sugie gave the magnitude as 18.9, while Nakamura said it was 19.9. The latter astronomer added that a weakly condensed coma was 15 arc seconds across, and a possible faint tail extended toward PA 260 degrees. The precise positions indicated the prediction by K. Muraoka required a correction of only -0.26 day. The comet passed perihelion on 1997 November 22. The maximum brightness was expected to reach about magnitude 17.5.
Copyright © 1997 by Akimasa Nakamura (Kuma Kogen Astronomical Observatory, Japan)
This is the recovery image obtained by Nakamura. The CCD image was taken on 1997 November 5.51, using a 0.60-m f/6 Ritchey-Chretien telescope.