Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2013 January 1
See Explanation.  Clicking on the picture will download 
the highest resolution version available.

A Double Star Cluster
Image Credit & Copyright: F. Antonucci, M. Angelini, & F. Tagliani, ADARA Astrobrallo

Explanation: Few star clusters are seen to be so close to each other. Some 7,000 light-years away, though, this pair of open or galactic star clusters is an easy binocular target, a lovely starfield in the northern constellation Perseus. Also visible to the unaided eye from dark sky areas, it was cataloged in 130 BC by Greek astronomer Hipparchus. Now known as h and chi Persei, or NGC 869 (above right) and NGC 884, the clusters themselves are separated by only a few hundred light-years and contain stars much younger and hotter than the Sun. In addition to being physically close together, the clusters' ages based on their individual stars are similar - evidence that both clusters were likely a product of the same star-forming region.

APOD Editors to Speak: RJN in Philadelphia on Jan. 3 & JTB in New York City on Jan. 4
Tomorrow's picture: gravity's lens

< | Archive | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
NASA Web Privacy Policy and Important Notices
A service of: ASD at NASA / GSFC
& Michigan Tech. U.