125P/Spacewatch

125P/Spacewatch is a Jupiter-family comet with a 5.53-year orbit around the Sun. It was discovered on 8 September 1991 by Tom Gehrels using the 0.91 m Spacewatch telescope at the Kitt Peak National Observatory. It was the first comet discovered with the use of a CCD, and also the faintest comet upon discovery up to that point. Its nucleus has a diameter of 1.66 km (1.03 mi).

The comet was discovered in images taken by the 0.91 m Spacewatch telescope at the Kitt Peak National Observatory by Tom Gehrels on September 8, 1991, as an essentially stellar object with an apparent magnitude of 21, with a tail more than 5 arcminutes long. Brian G. Marsden calculated a parabolic and an elliptical orbit, with the elliptical orbit suggesting an orbital period of 5.58 years and a perihelion date on 18 December 1990.

The comet was recovered on 21 March 1996 by the Spacewatch telescope from James V. Scotti and J. Montani, with an apparent magnitude of 17.6, a tail measuring 0.66 arcminutes long and a coma measuring 15 arcseconds across. The orbit calculated after the recovery indicates an orbital period of 5.56 years. During that apparition the comet experienced an outburst in late July 1996 and brightened to a magnitude of 14.5. During the 2002 apparition the comet brightened to a magnitude of 18.

• 125P/Spacewatch at the JPL Small-Body Database
• 125P/Spacewatch at Gary W. Kronk's Cometography
• 125P/Spacewatch at Seiichi Yoshida's website