171P/Spahr (0171P)

Type: Periodic Perihelion date: 25 September 2025 Perihelion distance (q): 1.8 Aphelion distance (Q) : 5.3 Period (years): 6.7 Eccentricity (e): 0.50 Inclination (i): 22.0 JPL orbit diagram COBS lightcurve Atlas T. B. Spahr (University of Arizona, Arizona, USA) discovered this comet with the 0.41- m f/3 Schmidt telescope in the course of the Catalina Sky Survey on 16 November 1998. He estimated the magnitude as 16.5 and noted a round coma 18 arc seconds across. No tail was visible. Additional images were obtained on 17 November, at which time the comet discovery was announced. A prediscovery image was later found on images taken by the Two Micron All Sky Survey (2MASS) on 13 November 1998. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 06-Oct-18 18.83 0.14 18.6 0.2 13-Oct-18 18.57 0.03 17.7 0.4 08-Nov-18 17.61 0.02 16.2 0.4 15-Nov-18 17.30 0.02 15.9 0.5 30-Nov-18 16.88 0.05 15.1 0.7 27-Dec-18 17.00 0.01 14.9 0.8 08-Jan-19 17.26 0.02 14.8 0.5