Ask Rufus: Once in a Blue Moon

August 25, 2013 11:31:21 AM

Rufus Ward - [email protected]


I think we have all heard the expression "once in a blue moon" without knowing what a blue moon is. We just know it is a rare or uncommon event. Last week we had a blue moon but that doesn't mean the moon was some strange shade of blue. There is actually disagreement over exactly when a blue moon occurs. 


The topic came up before dawn last Wednesday morning. Karen was headed to the wellness center to work out and I was headed to the walkway to meet up with Sharon Falkner for our morning 3-mile walk. All of our conversations turned to a beautiful full moon which the news had termed a blue moon. The question quickly arose as to what really is a blue moon. The moon, though beautiful when it broke through the clouds, did not look at all particularly blue or different. 


Each year is divided into four, 3-month seasons of winter, spring, summer and fall, with each month having a full moon. Traditionally the full moon of each month has been named with ancient Indian names often surviving. National Geographic gives those names including: January- Wolf Moon, February- Snow or Hunger Moon, March- Worm or Sap Moon, April- Pink or Egg Moon, May- Flower or Milk Moon, June- Strawberry or Rose Moon, July- Buck or Thunder Moon, August- Sturgeon or Green Corn moon, September- Harvest or Barley Moon, October- Hunter's or Travel Moon, November- Beaver or Frost Moon and December which is Cold or Oak Moon. Then there is the Blue Moon but where does it fit in? 


About every two and a half years one of the 3 month seasons will have 4 full moons rather than just 3. In 1937 the Maine Farmers' Almanac termed that uncommon occurrence as a "Blue Moon." The seasonal moons were termed early, mid and late and that terminology did not work with four moons in a season. So that the last seasonal full moon would continue to be called the "Late Moon" the third full moon in a season with four full moons was called a "Blue Moon". 


Then in 1946 Sky and Telescope Magazine published an article titled "Once in a Blue Moon." The article confused the definition given in 1937 slightly changing it. The new definition provided that a blue moon occurred when there were two full moons within one month. That change in definition took root after being used on a StarDate program on National Public Radio and further caused confusion as to when a blue moon occurs. 


That confusion about the correct definition only increased when an article with the 1946 definition appeared in the New York Times and a children's edition of the World Almanac. The final nail in the coffin of the original definition occurred when in the popular board game "Trivial Pursuit" a blue moon was defined as being the second full moon within one month. 


Today both definitions are often used, making blue moons not so rare as they once were, and definitely not as rare as hen's teeth. Be it 4 full moons in one 3 month season or two full moons within one month, "once in a blue moon" is one of those delightful phrases that gives color and life to our language.  


Is there ever really a true deeply blue colored moon? That is an event that does occur because of significant amounts of ash from volcanoes and fires or wind blown dust in the atmosphere. That moon may look blue but it is not a Blue Moon.

Rufus Ward is a Columbus native a local historian. E-mail your questions about local history to Rufus at [email protected]