Year of the Comet
Comet C/2011 L4 (PANSTARRS)

PANSTARRS information

Comet C/2012 S1 (ISON)

ISON information

Web Extras
Go deeper into the stories of Astronomy magazine. These online features bring you additional research, interviews, photos, and more our editors turned up while creating the stories for this issue.
July 2011
Lick-observatory-1888
It wasn’t easy building the first mountaintop observatory, but the effort was worth it.
By Richard Talcott // Published: May 23, 2011
Cocoon-Nebula
By Michael E. Bakich // Published: May 23, 2011
13_Sunflower-Galaxy
Not only do these galactic pinups help astronomers learn how the universe works, but they’re also pretty easy on the eyes.
By Bill Andrews // Published: May 23, 2011
Outer-solar-system-illus
Clyde Tombaugh’s discovery of Pluto in 1930 seemed to round out our planetary system, but astronomers have since found a vast expanse of similar objects in the Kuiper Belt.
By Richard Talcott // Published: May 23, 2011
Castor-sketches
Even a small backyard telescope can reveal the orbital motion of a binary star.
By Glenn Chaple // Published: May 23, 2011
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