There's a new comet in the southern hemisphere: Comet Lovejoy (C/2007 E2). Terry Lovejoy of Australia discovered it on March 15th using, remarkably, not a telescope but only an off-the-shelf digital camera. The green comet is too dim to see with the naked eye, but it is a nice target for backyard telescopes. After five days of monitoring, the comet's orbit is now known with some accuracy and it is possible to make predictions about Comet Lovejoy's future movements and brightness. Details.

After five days of tracking, Comet Lovejoy's trajectory is known. The orbit is cockeyed, almost perpendicular to the rest of the solar system. At the moment the comet is swooping up from below, moving from southern to northern skies. At closest approach to Earth (0.44 AU) in late April, Comet Lovejoy is expected to brighten to 7th magnitude, still not a naked-eye comet but easy to see through small telescopes.

BONUS--VENUS AND THE MOON: When the sun goes down tonight, step outside and look west. You'll see Venus and the slender crescent Moon beaming together through the glow of sunset. If you miss the pair on March 20th, try again on the 21st. They will be beautifully close together on both nights.