Happy Halloween, everyone.
Tonight’s full moon is the first full moon to fall on Halloween in 19 years. It is also a full blue moon because it is the second full moon of October, the first one occurring on Oct. 1.
The Halloween full moon reportedly rose at 10:49 a.m. ET today.
A blue moon, we have learned in research this morning, is also known as a blue hunter’s moon because hunters once used the moonlight to hunt and prepare for the winter. The moon does not actually appear blue.
As far as we can discern from our research, there have been times when the moon appeared blue in regions worldwide because of dust and smoke particles from nearby erupting volcanoes or forest fires. But the adjective blue now refers in this context to a rarity, an unlikely occurrence.
The first recorded appearance of the phrase “blue moon,” according to a Canadian folklorist/professor we met online, was in 16th century writings by Cardinal Thomas Wolsey—one of King Henry VIII’s closest advisers until he fell into disfavor—who wrote that his enemies “would have you believe the moon is blue.” Hence, a blue moon was considered an absurdity.
By the 1700s, the prof says, the phrase had evolved to mean “never.”
Hundreds of years later, however, James Hugh Pruett, a journalist, educator, and amateur astronomer from Oregon, mucked up the definition.
In a 1946 article in “Sky and Telescope Magazine” titled “Once in a Blue Moon,” Mr. Pruett incorrectly stated that a blue moon is the second full moon in any given calendar month, and his confused definition stuck.
Historically, a full moon was considered blue when it was the third of four full moons in a season, a season being defined as the time between an equinox and a solstice. (Some sources say the blue moon was the fourth in four seasonal moons.) This definition still has relevance as an alternate one.
There are 12 lunar cycles in a calendar year, hence 12 full moons, but “once in a blue moon,” there are 13.
A blue moon reportedly occurs once every 2.7 years.
The full moon on Oct. 1 was a harvest moon, which is the full moon that occurs nearest to the autumnal equinox on Sept. 22, which we observe as the first day of autumn. The last time a harvest moon happened in October was 2009.
Just what effects does the increased light during a full moon have on animals and human beings, alike? We leave that to you to research and conjecture. (If you have not seen the fabulous horror film, “An American Werewolf in London” (1981), we highly recommend viewing it on Halloween.)
Today is also the last day of Daylight Saving Time in 2020, so remember to give yourself an extra hour by “falling back” at 2 a.m. tomorrow. Chances are, your technology will beat you to it.
May your Halloween be safe and over the moon. We hear the howling in the distance.
Ann G. Sjoerdsma, 10/31/20