Explanation:
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 recently 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 can be seen spanning more than a
full moon toward the direction of the
constellation of the
Fox (Vulpecula).
On the far right of the
above image is the open cluster of stars NGC 6802.
