GREEN COMET ISON:

Comet ISON is brightening as it approaches the sun. At the moment it is glowing like a 10th magnitude star, too dim for naked-eye viewing but an easy target for many telescopes on Earth. "This is what the comet looked like on Oct. 8th using the 0.8m (32 inch) Schulman Telescope," reports Adam Block from the University of Arizona Skycenter atop Mount Lemmon:
 ISON's green color comes from the gases surrounding its icy nucleus. Jets spewing from the comet's core contain diatomic carbon (C₂) and cyanogen (CN: a poisonous gas found in many comets). Both substances glow green when illuminated by sunlight in the near-vacuum of space.

"I am certain more images of Comet ISON will be coming out shortly as it increases in brightness during its dive towards the Sun," adds Block. "Here is hoping it survives that rendezvous on Nov. 28th and emerges as something spectacular on the other side!"

Although the comet is very faint, finding it is easy. Comet ISON rises alongside Mars in the eastern sky just before dawn. Amateur astronomers, if you have a GOTO telescope, enter these coordinates. Special dates of interest include Oct. 13-15 when Mars, Comet ISON, and the first magnitude star Regulus will be clustered in a patch of sky less than 3^o apart. Red Mars and blue Regulus will form a beautiful naked eye "double star" in the early morning sky. Sky maps: Oct. 10, 11, 12, 13, 14, 15.



 Source:
http://www.spaceweather.com/