Watch for it tomorrow night. . .

 

“Sky & Telescope magazine has traced the history of the term in at least two articles and it has even been part of the change of how the term is used.

Here is a summary of what the articles describe:

• The original usage of the term was like the modern statement “When pigs fly.”
• Another described an infrequent event related to volcanic eruptions. The dust ejected high into the atmosphere, can give the moon and sun and bluish hue when see through the dust. While infrequent, blue moons do occur.
• A usage closer to the popular modern concept can be traced to the Maine Farmers’ Almanac that related the term an extra full moon during a season. The seasons normally have three full moons. When a season has four, the third one is called “Blue Moon.” Historically, the months had names, such as Harvest Moon, Egg Moon or Lenten Moon. Because those full moons were related to specific events related to the seasons, there came a time when a season had an extra full moon without a name; the third month in that series was named “Blue Moon.”
• Sky & Telescope also stated that it contributed to the popular notion with articles in 1946 and 1950 that cited the Maine Farmers’ Almanac, but added that a second full moon in a month was a “Blue Moon.”

http://jeffreylhunt.wordpress.com/2012/08/30/august-31-blue-moon/