Comet and Earth to have rare close encounter

(Read more of Joe Rao's story on space.com)

Typically during the course of a year about a dozen comets will come within the range of amateur telescopes. Most quietly come and go with little fanfare, but during the upcoming weeks one rather small comet will be making an unusually close approach to the Earth.

On Oct. 20, Comet Hartley 2 will pass just over 11 million miles from Earth. During October it should be easily visible in small telescopes, binoculars and from sites with dark enough skies even with the naked eye.

On November 4, 2010, NASA is sending EPOXI, an extended mission of the Deep Impact fly-by spacecraft, to study the comet. The mission will conduct an extended encounter with Hartley 2, studying the comet using all three of the spacecraft’s instruments (two telescopes with digital colour cameras and an infrared spectrometer). The spacecraft's name is derived from this mission’s two tasked science investigations—the Deep Impact Extended Investigation (DIXI) and the Extrasolar Planet Observation and Characterization (EPOCh).

On its original mission, the Deep Impact fly-by spacecraft had a companion probe spacecraft that was smashed into comet Tempel 1 to reveal for the first time the inner material of a comet.

This video sky map shows how to spot the comet.