For a District that has a Moon Lodge - Lockbourne No. 232 - here's an interesting bit of information.

We just had a Blue Moon on November 21st.  So what really is a Blue Moon?  Since 1980, pop culture has contended that a Blue Moon is when a full moon occurs twice in one month.  That erroneous information was originated by Deborah Byrd who used it on her popular National Public Radio program, "StarDate" on Jan. 31, 1980.  After that broadcast, the "new rule" started creeping into pop culture items such as newspapers, magazines, and the game Trivial Pursuit.

But the original meaning of a Blue Moon is much different.  It originally referred to four full moons in one season, as opposed to the usual three, for a total of 13 full moons in a year.  This happens only seven times in every nineteen year lunar cycle.

Full moons used to be termed by season as early, mid and late (early summer moon, mid summer moon, late summer moon, etc.).  When four full moons occurred in one season, the third one was then termed a "blue moon", so that the fourth could stay the "late moon".

So why was November 21st a Blue Moon?  Even though the last full moon of this season occurs on December 21st, the moon turns full at 3:13a.m. EST.  That's over 15 hours before winter officially begins on the winter solstice making December 21st a Fall moon.  Along with the other full moon dates this Fall (September 23rd, October 22nd and November 21st) December 21st is the last of four full moons in the season, making November 21st a Blue Moon.

For more information check out Joe Rao's Skywatching column on SPACE.com.