Analysis of information sources in references of the Wikipedia article "Blue moon" in English language version.
{{cite book}}: CS1 maint: location missing publisher (link)It's a seasonal Blue Moon: the third of four full moons to occur in a single season.
Note that the blue colour surrounding the Moon in these images is the result of atmospheric and camera effects. The Moon itself does not change colour.
One explanation connects it with the word belewe from Old English, meaning, "to betray." Perhaps, then, the Moon was "belewe" because it betrayed the usual perception of one full Moon per month? That would make sense.
There are two kinds of blue moons, but they don't actually look blue. One type is called a calendar blue moon, and the other type is a seasonal blue moon.
So, 'blue moon' as most of us today know it, is modern American folklore, but with a long interesting history involving calendars and the measuring of the year. Still, no matter what meaning you give it, blue moons are pretty rare, and everyone knows what you mean when you say "once in a blue moon!"
The zodiac blue moons can occur in any month between the 18th to the 23rd day of the month.
belewe, variant of blue, adj. and n.
Quite where the term blue moon came from is unclear. It may be a mispronounciation of the disused word "belewe" which means 'to betray'. This may be a reference to the betrayal of the usual idea of having one full moon in each month or perhaps the "betrayal" by the Moon of worshippers attempting to determine the position and duration of Lent in the calendar year.
The 1937 Maine Farmer's Almanac reveals the traditional meaning of "Blue Moon."
Some three years later, in March 1946, an article entitled "Once in a Blue Moon" appeared in Sky & Telescope (page 3). Its author, James Hugh Pruett (1886-1955), was an amateur astronomer living in Eugene, Oregon, and a frequent contributor to Sky & Telescope. Pruett wrote on a variety of topics, especially fireball meteors. In his article on Blue Moons, he mentioned the 1937 Maine almanac and repeated some of Lafleur's earlier comments. Then he went on to say, "Seven times in 19 years there were — and still are — 13 full moons in a year. This gives 11 months with one full moon each and one with two. This second in a month, so I interpret it, was called Blue Moon."
While this name is not Native American, it is included here for completeness.
I've checked with several native speakers of Czech and found nothing like "blue Moon." Secondly, an e-mail correspondent told me several years ago that calendar printers would always print a full Moon in red except when it was the second one in a month; then it would be printed in blue! That sounded wonderfully plausible -— until I looked at older calendars and found none that were so.
The full Moon of Sunday, August 22nd, will be a "Blue Moon" according to the original — but not the most popular — definition of the phrase.
Editors and contributors to Sky & Telescope have traced the traditional astronomical definition to the Maine Farmers' Almanac in the late 1930s.
A seasonal Blue Moon is the traditional definition of a Blue Moon and refers to the third full moon in a season that has four full moons according to NASA.
Many years ago in the pages of Natural History magazine, I speculated that the rule might have evolved out of the fact that the word "belewe" came from the Old English, meaning, "to betray." "Perhaps," I suggested, "the second full Moon is 'belewe' because it betrays the usual perception of one full moon per month." But as innovative as my explanation was, it turned out to be completely wrong.
Neither the Oxford English Dictionary (OED), nor the Online Etymology Dictionary provide any support for the idea that the term "blue moon" has any connection to Old English belǽwan "to betray". To the contrary, the OED indicates that the "blue" in "blue moon" is derived from the familiar color word, which is a loanword from French (although French in turn got the word from a Germanic language). The OED does indicate that the color word blue was spelled "belewe" in some Middle English manuscript or manuscripts.
... may cause the moon to have a blue tinge since the red light has been scattered out.