Green comet 103P/Hartley 2 is approaching Earth for a close encounter on Oct. 20th. At that time, the comet will be only 11 million miles from Earth and should be dimly visible to the naked eye from dark sky sites. It already looks great through backyard telescopes:


© Rolando Ligustri
Amateur astronomer Rolando Ligustri took this picture on Oct. 1st using a 14-inch Global Rent-a-Scope in New Mexico. It shows Comet Hartley beside the spectacular Pacman Nebula (NGC 281), a star-forming cloud some ten thousand light years from Earth. "This is a very nice comet for telescopes and binoculars," says Martin Gembec who took a similar picture from his backyard observatory in the Czech Republic last night. "It has a [green atmosphere] almost 0.5 degrees wide and shines like a 7th magnitude star."

Two weeks after Comet Hartley has its close encounter with Earth, NASA will have a close encounter with the comet. The EPOXI spacecraft (formerly known as Deep Impact) is hurtling toward Comet Hartley now, and on Nov. 4th it will fly 435 miles from the comet's active icy nucleus. The encounter will mark only the fifth time in history that a spacecraft has been close enough to image a comet's core.

Until then, amateur astronomers can monitor the comet as it glides through the constellation Cassiopeia in the evening sky. A finder chart from Sky and Telescope shows the comet passing by a variety of stars and deep-sky objects, offering many photo-ops in the nights ahead.

More images: from Dale Ireland of Silverdale, Washington; from Kevin Black of Winnipeg, Manitoba Canada; from Alan Dyer of near Cluny, Alberta, Canada