Terry Lovejoy of Thornlands, Queensland, Australia, has discovered a 9th-magnitude comet in the southern constellation Indus. In reporting the find to the Central Bureau for Astronomical Telegrams (CBAT), Lovejoy described the comet as having a green, 4' coma with a slight extension to the southwest. Its position on March 15.73 Universal Time was right ascension 20h 44.1m, declination -51° 14' (equinox 2000.0), and it appears to be moving 0.55° per day north-northwestward, toward Alpha Indi.
Within 24 hours the discovery was confirmed by John Drummond of Gisborne, New Zealand, and the new comet (designated C/2007 E2 but not yet officially named) was announced on IAU Circular 8819.
Lovejoy's find opens a new chapter in the long and glorious history of comet hunting. It appears to be the first case of a comet discovered in a systematic survey with an off-the-shelf digital camera: a Canon 350D with a zoom lens set to 200-mm focal length at f/2.8. Lovejoy spotted the object near the frame edge in 16 exposures of 90 seconds each. He prepared the cropped composite here from eight of these frames. North is toward left, and the field about 0.8° wide.
Orbit Not Yet Known
As of this posting, the comet's orbit is still unknown. Observers with the necessary experience are urged to make astrometric observations that will help in determining its orbit. For information about this kind of work, and where to submit measurements, see these guidelines prepared by the Minor Planet Center in Cambridge, Massachusetts.
Please check the online version of this AstroAlert on Sky & Telescope's website for possible minor updates:
For further developments concerning this object, stay tuned to our website's observing highlights. Good luck, and clear skies!
Roger W. Sinnott
Sky & Telescope