This Friday Night Features A Rare Blue Moon

More celestial excitement happens this week!

The definition of "blue moon" has nothing to do with the color, but rather with the frequency of a full moon.

There are two different ways of calculating which full moon is a Blue Moon.

• Blue Moon = The third full moon in an astronomical season with 4 full moons (versus the normal 3)
• Blue Moon = The second full moon in a month with two full moons.

Occasionally the moon can actually appear blue, but that has to do with having a rare type of dust, usually caused by forest fires or volcanoes, in the atmosphere.

The last blue moon was August 31, 2012, almost 3 full years ago.

This isn't quite as "exciting" as my usual "celestial excitement", but I'm still a sucker for astronomy stuff.