Collinder 399: The Coat Hanger . ... Credit Copyright: John Chumack 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 . ... NASA Web Site Statements, Warnings, and Disclaimers . ...