Comets - 155P/Shoemaker - 0155P
Type Periodic Perihelion Date 15 November 2019 Perihelion Distance (q) 1.8 Aphelion Distance (Q) 11.4 Period (Years) 16.9 Eccentricity (e) 0.73 Inclination (i) 6.4 Click for NASA orbit diagram
Hills Observatory: 1 January 2013 to 26 May 2020
COMETS COMETS
DEEP SKY DEEP SKY
Caroline and Eugene Shoemaker (Palomar Observatory, California, USA) discovered this comet on a photographic plate obtained with the 0.46-m Schmidt telescope on 10 January 1986. 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 12 January. He gave the magnitude as 13 and noted the short tail extended toward PA 86°. The first orbit was calculated by B. G. Marsden based on 14 positions gathered during the period of 10-20 January 1986. He noted that the comet was moving in an elliptical orbit with a perihelion date of 20 December 1985 and had a period of 15.3 years. He added, "The revolution period is still rather uncertain." Marsden revised his orbit on 31 January 1986, giving the perihelion date as 19 December and the period as 16.34 years. Ultimately, the perihelion date proved to be 18 December, while the period was 16.91 years. During the apparition of 1985-1986, several observers provided magnitude estimates of 13 shortly after mid-January. The comet was followed during the next few months as it steadily faded and was last detected with the Spacewatch telescope (Steward Observatory, Arizona, USA) on 14 May. The comet was independently recovered on 9 September 2002 by T. Oribe (Saji Observatory) and on 12 September 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 4 and 7 September . The comet was well observed at this apparition and numerous observers indicated the brightness attained a maximum value between 13 and 14. Date 10x10 mag Error Kphot mag Coma ' 05-Oct-19 17.17 0.04 16.0 0.5 12-Oct-19 15.63 0.01 15.2 0.4 29-Oct-19 16.39 0.04 14.7 0.6 30-Nov-19 16.52 0.01 15.3 0.6 09-Dec-19 16.65 0.02 15.6 0.5 22-Dec-19 16.66 0.02 15.6 0.4 22-Dec-19 16.66 0.02 15.6 0.5 29-Dec-19 16.66 0.02 15.4 0.5 05-Jan-20 16.52 0.04 15.2 0.5 18-Jan-20 16.78 0.02 14.8 0.8 25-Jan-20 16.82 0.02 15.6 0.6 03-Feb-20 16.74 0.03 14.8 0.6 16-Feb-20 16.72 0.01 15.0 0.7 19-Mar-20 17.86 0.05 15.7 0.7 29-Mar-20 18.32 0.06 17.1 0.4