File:Comet 52P Harrington-Abell 2MASS.jpg

English: Atlas Image mosaic of comet 52P/Harrington-Abell, which was serendipitously observed by 2MASS on 1998 Oct 8 UT and is among twenty comets included in the 2MASS Second Incremental Data Release. Comets, of course, are within our Solar System and orbit the Sun, and therefore do not move sidereally (that is, as the stars do). Astronomers, however, have determined the ephemerides, or orbital parameters, for large numbers of known comets, so their positions in the sky along their orbits can be accurately predicted. Occasionally, comets, asteroids, and even planets can "accidentally" wander into the Survey. Comets reflect sunlight, yet near-infrared photometry can provide useful compositional and structural information about these objects. This comet was seen optically to experience a significant outburst in 1998 July (IAUC 6975) and became unusually bright by August (IAUC 6994), exceeding visual magnitude 11 by 1999 February (IAUC 7113). Its coma diameter was 1-2´ and tail length of about 2´ in 1998 (IAUC 6975). In 2001 December the comet was seen to have split into two (IAUC 7769), following a brightening by more than two magnitudes between 2001 August and September (IAUC 7773).