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.
