Guest Author - Lea Terry

Aided by multi-million dollar, highly sophisticated telescopes and other equipment, astronomers have obtained an amazingly detailed look at the universe. However, a recent discovery shows why astronomy is one of the few sciences where amateurs have made equally notable contributions.
The recently discovered Comet Lovejoy, which will pass closest to Earth April 24-26, was observed not with a high-tech astronomical instrument, but with an off-the-shelf digital camera--the Canon 350D, in fact. Terry Lovejoy of Thornlands, Queensland, Australia, discovered the comet on March 15th, as part of a comet-hunting survey of the sky that Lovejoy began over two years ago. So how did Lovejoy turn a run-of-the-camera into a comet-hunting tool? By using a zoom lens set to 200-mm focal length at f/2.8, with exposures of 90 seconds each. Lovejoy was able to see the comet near the edge of the frame in 16 of the exposures. This is the first known discovery of a comet using a store-bought digital camera.
Comet Lovejoy’s green color indicates a significant presence of cyanogens and diatomic carbon. With an estimated magnitude of 9.5, the comet is too faint to be seen by the naked eye--it’s 15 times dimmer than the faintest object that can be seen without aid. However, amateur astronomers should be able to glimpse it with the help of binoculars or a small telescope. Comet Lovejoy should grow a little brighter, but still only reach +7.5, which is over twice as dim as the faintest star that can be seen by the naked eye.
Comet Lovejoy will move toward the north, so observers in the Northern Hemisphere will have the best chance of seeing it, particularly starting the second week of April. At this time, the comet will be visible low in the southeast sky, between the constellations of Capricornus the Sea Goat and Sagittarius the Archer. Between April 20-25, the comet will pass through the southern half of Aquila the Eagle, and will appear to cross right through the Milky Way. Near the end of April, the comet will pass between Lyra the Lyre and Hercules, and will be almost directly overhead in the early morning hours.