Sunday, September 2, 2012

Once in a Blue Moon


August 31 had a full Moon as did August 1. So by meaning #7 in this Sky & Telescope article the second was a "Blue Moon".

From a Washington Post article:

The “Maine rule”: Going back two centuries, the blue moon was defined as the third moon out of four in a given season, according to the Maine Farmers’ Almanacs going back to 1819. (Donald W. Olson, Richard Tresch Fienberg and Roger W. Sinnott, from Sky & Telescope, went searching for the Maine Farmer’s Almanacs to confirm this.)

Normally there are three full moons in any season, each with a name, such as fruit moon, paschal moon or harvest moon. Since sometimes there are 13 moons in a year, the third moon out of four in a season became the blue moon – a placeholder name -- so that the other moons would keep their rightful place in a seasonal order.

Blue Moons of either of these meanings occur about every 29 months. Hence "Once in a Blue Moon" most often means "very infrequent" (meaning #4 in the Sky & Telescope article).

Here, perhaps, is a more satisfying Blue Moon. ;-)