A comet’s tail
Hartley 2 will pass nearest Earth October 20
By Ron Cowen
Comet Hartley 2 is already producing quite a tail and is expected to put on an even better light show when it nears Earth and the sun in late October. But the best look at the comet will come November 4, when a NASA spacecraft will fly within 700 kilometers of the icy object.
Hartley 2, formally known as 103P/Hartley, circles the sun every 6.46 years. The comet comes within 17.7 million kilometers of Earth, or about 45 times the Earth-moon distance, on October 20. From dark skies in the Northern Hemisphere, the comet should be visible to the naked eye as a fuzzy object in the constellation Auriga. Binoculars or a small telescope may be required to see Hartley 2 from urban areas. The comet, discovered in 1986, makes its closest approach to the sun on October 28. Observers in the Southern Hemisphere should have a good view of the comet in late November as it heads away from Earth.