Collinder 399: The Coat Hanger January 1, 2009 Is this coat
hanger a star cluster or an asterism? This cosmic hang-up has
been debated over much of last century, as astronomers wondered
whether this binocular-visible object is really a physically
associated open cluster or a chance projection. Chance star
projections are known as asterisms, an example of which is the
popular Big Dipper. Recent precise measurements from different
vantage points in the Earth's orbit around the Sun have
uncovered discrepant angular shifts indicating that the Coat
Hanger is better described as an asterism. Known more formally
as Collinder 399, this bright stellar grouping is wider than the
full moon and lies in the constellation of the Fox (Vulpecula).
On the far right of the image is the open cluster of stars NGC
6802. Topics: Constellations, Astrology, Stars, Ursa Major, Star
cluster, Alpha Persei Cluster, Vulpecula, Asterism, Vulpecula
constellation, Brocchi's Cluster, Open clusters, Astronomy