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: Open cluster NGC 752 in Andromeda is a very old open cluster estimated to be approsimately 1.6 billion
years-old but still younger than the well-known old open cluster M67 in Cancer.
The cluster is comprised of approximately 100 member stars and dominated by many mag 9 to mag 10 stars and which includes an impressive carbon
star (SAO 55138, mag 7.11) due south of the core which forms an impressive triangle with two other neighbouring and bright stars (mags 8.85
and 9.56). NGC 752 is well-detached from the backround sky and well-dispersed in a field spanning the apparent diameter of nearly two full
moons. The cluster has been estimated to lie at a distance of 1,490 light-years away. The two small and dim galaxies visible in the image below
are PGC 7466 (mag 17.4, 0.3'x0.2') lower left and PGC 2116140 (mag 17.9, 0.2'x.0.2') upper right. NGC 752 was discovered by Giovanni Batista
Hodierna (1597-1660) in 1654.
Please click on the image below to display in higher resolution (1200 x 900)