By Rod Hill on 2010-10-16
Comet 103P/Hartley 2 is positioning itself for its closest approach to Earth on October 20, 2010. This bring the comet nearer to Earth since its 1986 discovery, and makes it one of the nearest visits of any comet in the last few centuries.
For the past few weeks, Comet 103P/Hartley 2 been fairly dim at magnitude 5 or 6, best viewed from very dark and moonless skies for experienced observers. In the coming days, the comet is expected to be barely visible to the unaided eye but best spotted in binoculars and telescopes. Unfortunately, the next full moon will be on October 22 and will make the viewing of Hartley 2 tougher for the rest of the month.
During the week of October 18, the best time to look for Comet 103P/Hartley 2 will be at dawn when it is high above the northeast horizon. The fuzzy visitor will pass by the brilliant star Capella in the constellation Aurgia. On October 20, the comet will be 6 degrees to the lower right of Capella. At this time, it will be 0.12 astronomical units from Earth and at a magnitude of 4, which is about the brightness of the stars in the handle of Ursa Minor, the Little Dipper. Look for a faint fuzzy patch of the comet’s nucleus. Viewing will be best through binoculars. The comet’s kryptonite green halo is diffuse and can be difficult locate. Towards the end of the month, the comet will be lower in the constellation of Gemini.
By November, Comet 103P/Hartley 2 will be fading in view as it moves near Sirius, away from both the Sun and Earth. On November 4, a NASA EPOXI spacecraft, a continuation of the Deep Impact mission, will fly by the comet's small nucleus which is estimated to be only a mile in diameter. The probe will take pictures and other data at some 600 miles.
Enjoy this comet because at this moment in time it's the brightest visitor which we will see in 2010.
* The above is courtesy of Jim Todd, OMSI Planetarium Manager
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