155P/Shoemaker 3
Copyright © 2002 by NEAT
This image was obtained by the Near Earth Asteroid Tracking (NEAT) program on 2002 November 20.51.
Caroline and Eugene Shoemaker (Palomar Observatory, California, USA) discovered this comet on a photographic plate obtained with the 0.46-m Schmidt telescope on 1986 January 10.47. They estimated the magnitude as 10 (although it was later revised to 12) and described the comet as moderately condensed, with a short tail. The comet was confirmed by B. A. Skiff (Lowell Observatory, Anderson Mesa Station, Arizona, USA) on January 12.37. He gave the magnitude as 13 and noted the short tail extended toward PA 86°.
The first orbit was calculated by B. G. Marsden and published on IAU Circular 4166 (1986 January 21). Based on 14 positions gathered during the period of 1986 January 10-20, Marsden noted the comet was moving in an elliptical orbit with a perihelion date of 1985 December 20.92 and a period of 15.3 years. He added, "The revolution period is still rather uncertain." Marsden revised his orbit on IAU Circular 4171 (1986 January 31). Based on 28 positions obtained during the period of January 10-22, he gave the perihelion date as December 19.10 and the period as 16.34 years. Ultimately, the perihelion date proved to be December 18.56, while the period was 16.91 years.
Apparition of 1985-1986: Several observers were providing magnitude estimates of 13 shortly after mid-January. Several observatories followed the comet during the next few months as it steadily faded. It was last detected with the Spacewatch telescope (Steward Observatory, Arizona, USA) on May 14.20.
Apparition of 2002: This comet was independently recovered on 2002 September 9.78 by T. Oribe (Saji Observatory) and on September 12.81 by A. Nakamura (Kuma Kogen Observatory, Japan). The magnitude was then given as 18.0 and 18.6, respectively. Prediscovery images were subsequently found on photographs obtained by T. Seki (Geisei, Japan) on September 4.80 and 7.81. The comet was well observed at this apparition and numerous observers indicated the brightness attained a maximum value between 13 and 14.