The Double Cluster in Perseus

Object Information:: The Double Cluster in Perseus, NGC 869 and NGC 884; Distance - 7,000 light years; The dense grouping of stars in the image above is known as an open cluster [sometimes also known as a "galactic cluster"]. Open clusters are believed to originate in the same general area of space from the same local gas clouds.; The famous double cluster in Perseus was known in historic times (probably even pre-historically), and first cataloged by the Greek astronomer Hipparcos.; Both clusters are situated in the Perseus OB 1 association, and also only a few hundred light-years apart, at a distance of over 7000 light years. They are both quite young: NGC 869 is listed at 5.6, NGC 884 at 3.2 million years (Sky Catalog 2000); their hottest main sequence stars are of spectral type B0. They are approaching us at 22 (NGC 869) and 21 (NGC 884) km/sec, respectively.; For more information on open star clusters see:; http://www.seds.org/messier/open.html; http://www.seds.org/messier/xtra/ngc/n0869.html

Imaged at:: Grandview Campground, Inyo National Forest, CA

Equipment:: Optics - Takahashi Epsilon 160; Mount - Astro-Physics 900 GTO,; Camera - Santa Barbara Instrument Group (SBIG) ST-2000XM CCD,

Exposure Information:: September 17, 2004; RGB Image - 120 sec. each; Each color component is a median combination of 5 sub-exposures.