Blue Moon Soon

[Not Afraid]

Well, maybe not.

Tonight will be the second full moon in a month - something that is commonly called a "Blue Moon". Apparently, our usage is incorrect.

Kelly Beatty, editor of Night Sky magazine and executive editor of Sky and Telescope, tells Robert Siegel that a blue moon actually refers to the phenomenon of having four full moons in a season, which ordinarily has three.
Beatty also acknowledged that his magazine had a hand in giving the misconception credence. Sky and Telescope magazine recently put out a press release explaining its role in perpetuating the myth. It read, in part:

Our 1946 writer, amateur astronomer James Hugh Pruett (1886-1955), made an incorrect assumption about how the term had been used in the Maine Farmers' Almanac, where it consistently referred to the third full moon in a three-month season containing four. (By this definition there is no blue moon in May or June 2007, and the next one happens in May 2008.)

Audio here.