BLUE MOON of Cincinnati

Blue Moon over Cincinnati (open in new window for a bigger pic)

On August 31 we had a "Blue Moon."  It didn't appear blue in color or anything it's just a strange label for insignificant full moon.  But anything to get people looking at the Moon!

What is a Blue Moon?

It depends on who and when you ask.  Today a Blue Moon refers to the second full Moon in a calendar month. The term, as we now know it, only dates back to a 1946 Sky and Telescope magazine article by James Hugh Pruett. The term did not become mainstream until 1980 when the radio program StarDate used the Pruett definition - and the meaning has stuck ever since.

The earliest reference to a Blue Moon dates back to a sixteenth century poem.

    If they say the Moon is blue
    We must believe that it is true.

Here the term Blue Moon means something that never happens. Calling the Moon blue is like calling the Sun cold. You would have to be blind to call the Moon blue. Ironically, the joke that the Moon is made of green cheese also originated in the 1500s.

Of course the term “Blue Moon” has appeared in several popular songs dating back to the 1930s. Blue Moon of Kentucky was written by bluegrass legend Bill Monroe in 1944. And who can forget Elvis singing Blue Moon? In these songs, the term refers to a time of loneliness and sorrow, not the second full Moon in a month.

The Moon can actually appear blueish on very rare occassions.  When enough particles are in the atmosphere, like after a volcanic eruption, the Moon can appear a little tinted as in this picture.

On the flip side, what do you call it when you have two New Moons in one month? So far there is no such term. I suggest calling it a Black Moon. That would actually make sense.

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