MASSACHUSETTS — Sky gazers, take note: This weekend brings more than a brief respite from the stresses of the workweek. It also brings a chance to catch a glimpse of a rare seasonal blue moon over Massachusetts.
The blue moon will adorn the night sky on Sunday. The last seasonal blue moon occurred on Halloween in 2020.
There are two instances in which we experience a "blue" moon. Many of us are familiar with the first instance: A blue moon happens when there are two full moons in a calendar month. The second is usually also simply called a blue moon, according to The Farmers' Almanac.
Turns out, that definition is more folklore than truth, The Farmers' Almanac says:
The modern custom of naming the second full moon of any month a "blue moon" was actually based on a misinterpretation in an article written by James Hugh Pruett in the March 1946 issue of "Sky & Telescope" magazine. Titled "Once in a Blue Moon," Pruett incorrectly summarized what he read in the Maine Farmers' Almanac.
second instance — the accurate definition of a blue moon and the type we'll see
Sunday — actually has to do with the number of full moons in a single season.
Typically, there are 12 full moons each year, or three per season. If four full
moons occur during a single season, the third is referred to as a "blue
moon." [I think this means the 4th not 3rd but maybe I'm wrong - but today IS the 4th Sunday]
If you miss this weekend's blue moon, you'll have a chance to catch the next one in just three short years. The next seasonal blue moon will grace the skies on Aug. 19, 2024, followed by May 20, 2027.
So, is a blue moon actually blue? Not usually, according to EarthSky,org.
you see a photo of a blue moon, chances are it was taken using a camera with a
blue lens filter. On rare occasions, usually after vast forest fires or major
volcanic eruptions, the moon has reportedly taken on a bluish or lavender hue,
according to The Farmers' Almanac. Soot and ash particles propelled into the
Earth's atmosphere can sometimes make the moon appear blue.[Northern CA might really see a blue moon tonight!]
The blue moon is also a sure sign that autumn is on its way, according to EarthSky.org. Since Sunday's blue moon happens considerably closer to the fall equinox than the summer, the moon shares similar characteristics to September's harvest moon. By definition, the harvest moon is the closest full moon to the autumn equinox. The true harvest moon will come on Sept. 20.