Comet Lovejoy is discovered by Australian, and its green

By William Atkins
Saturday, 31 March 2007 20:10

Science - Space

Australian amateur astronomer Terry Lovejoy discovered a green comet on March 15, 2007 with a digital camera. For his efforts, the comet has been named Comet Lovejoy, with an official designation of C/2007 E2.

Comet Lovejoy, a non-periodic comet, has its nearest approach to the Earth—66 million kilometers (41 million miles)—between April 24 and 26, 2007, but can now be seen in the skies of the Southern Hemisphere and will soon be viewable in the Northern Hemisphere.

In both cases, binoculars or a small telescope will be needed to see it. A naked eye observation is not possible because its maximum brightness is expected to be only +7 when it reaches perigee (closest distance to the Earth) on April 25 within the constellation Aquila. Its perihelion (closest approach to the Sun)—163 million kilometers (101.3 million miles)—occurred on March 27, 2007.

The green color of the  9.5-magnitude Comet Lovejoy indicates that the comet contains cyanogen (the chemical compound CN2) and diatomic carbon (a two-atom molecule of carbon, C2).

Australian amateur astronomer Terry Lovejoy discovered his comet with a 350D Canon digital camera. He is from Thornlands, Queenstand, Australia. Lovejoy first saw the comet while it was passing within the southern constellation Indus (the Indian). He reported his finding to the Central Bureau for Astronomical Telegrams (CBAT), in Cambridge, Massachusetts, U.S.A.

The first independent confirmation of the discovery came from John Drummond of the Possum Observatory in Gisborne, New Zealand, on March 16. And, the comet’s first calculated orbit came from Brian G. Marsden of CBAT on March 19. Lovejoy’s discovery of this comet is believed to be the first one for an amateur with a common digital camera and the first by an amateur with the help of the Internet.

When first seen by Northern Hemisphere observers, Comet Lovejoy will be observable at dawn, positioned low in the southeastern sky. It will be located between the constellations Capricornus and Sagittarius. As mentioned earlier, between April 20 and 25, the comet will pass through the constellation Aquila.

Information on the Lovejoy Comet can be found on the Gary W. Kronk’s Cometography Web site at: http://cometography.com/lcomets/2007e2.html.

Additional information on the Lovejoy Comet is found at the Possum Observatory Web site at: http://www.possumobservatory.co.nz/comet2007e2-lovejoy.htm.

Terry Lovejoy’s astrophotographs can be seen at: http://www.pbase.com/terrylovejoy.

An interview with Terry Lovejoy appears at the IceInSpace Web site: http://www.iceinspace.com.au/index.php?id=84,384,0,0,1,0.