August Blue Moon

Skywatchers all over the world jumped at the chance to view and photograph Friday's (Aug. 31) full moon, the last so-called "blue moon" until July 2015.

Friday's full moon was the second one to rise during the month of August, following the full moon of Aug. 1.

This qualifies it as a blue moon, according to the popularly accepted (but incorrect) definition of the term.

"Blue moon" orginally referred to the third full moon in a season that has four full moons instead of the usual three.

But in 1946, a writer for "Sky and Telescope" magazine erroneously reported the second-full-moon-in-month meaning, and the definition stuck.