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How much do you know about the moon?

By: Anna Norris on Sept. 16, 2013, 12:29 p.m.
Blue moon rising

Photo: Margaret Buchanan/Flickr

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Blue moon

Even more rare than the supermoon, a blue moon can be generalized as a second full moon in a calendar month (though some argue that this is an incorrect use of the term). Most seasons have just three full moons, but sometimes there are four — and the technically-correct blue moon is the third of four full moons in that season. The most recent blue moon was on Aug. 21, and the next one will occur in 2015.