G. Sostero, N. Howes and E. Guido succeeded in recovering comet P/1994 X1 (McNaught-Russell) on May 29, 2012 near the borders of the constellations Sagitta/Delphinus/Aquila. On images taken with the Faulkes Telescope North comet P/2012 K7 (McNaught-Russell) showed a diffuse 3" coma of total magnitude 19.5. It will pass perihelion on its 18.25 years orbit in December, expected to peak at magnitude 13-14 (CBET 3132). It should be brighter than magnitude 16 between September 2012 and January 2013. During this time it will move through the constellations Vulpecula, Sagitta, Delphinus, Equuleus and Aquarius. Thus it will be well-placed in the evening sky during the most interesting weeks for users of larger instruments. The comet was assigned the permanent designation 262P/McNaught-Russell.

In winter 2012/13 the comet surprised the observers, by getting significantly brighter than expected. On the base of 3 observations by 2 members of the German Comet Section and 25 international observations the brightness evolution can be represented approximately by the following formulae

These yield a maximum brightness of 11.0 mag on Jan. 20, 2013. The coma diameter increased slowly, from 2.5' (about 110.000 km) to 4' (170.000 km) on Jan. 20. Starting at the end of January it was estimated to be only about 1' (75.000 km). Throughout the apparition the coma was rather diffuse (DC 2-3). No tail could be detected visually.

Total Brightness and Coma Diameter

Andreas Kammerer

FGK observations