Open star clusters are widely distributed in our galaxy and represent a loose collection of stars which number from a
few dozen to a few hundred stars and are weakly-held gravitationally. Perhaps the three most famous such open clusters
are the Pleiades (M45) in Taurus, the Beehive (M44) in Cancer and the double cluster in Perseus. They are all
characterized with a handful of hot and white prominent stars and nebular material surrounding these stars.
Note: The open cluster NGC 7789 in Cassiopeia is a bright and richly populated cluster comprised of approximately 300 member stars which are evenly distributed and well detached from the background sky. This cluster lies at a distance of 7620 light-years away with an apparent diameter of 25'. As indicated by the various red giants in the image below, the cluster is advanced in age and which has been estimated to be approximately 1.6 billion years-old. NGC 7789 was discovered by Caroline Herschel in 1783. It lies a few degrees west of Caph (â-Cas, mag 2.26) and is best observed using low magnifications during late fall and winter when it is placed directly overhead when looking due northeast.
Please click on the image below to display in higher resolution (1200 x 900)
Cr 460, OCL 269
II 2 r
RA / Dec:
23h 57m 26s /
56° 44' 00"
25' x 25'
Dec 11, 2007
18:45 - 21:00 UT+2
AP 160 f/7.5 StarFire EDF
AP 1200GTO GEM
SBIG LRGB + IR-block