A calendrical quirk of the universe is uniting a super moon, blue moon and total lunar eclipse this week — a rare assembly that hasn’t happened over the continental U.S. since 1866.
Adding to the cosmic indulgence in Wednesday’s pre-dawn sky is the moon will be near perigee, when the Earth’s only natural satellite is closest in its orbit and may appear slightly brighter and bigger, thus earning it the moniker “super moon.”
A blue moon is popularly defined as the second full moon in a month, which is an event that happens about every 2.7 years on average.
Even for austere astronomers, who frown on routine celestial events getting undeserved hype, this triple lunar treat is an affair of note.
“It’s an astronomical trifecta,” said Kelly Beatty, a senior editor at Sky & Telescope magazine. “Situations like this that cause people to go out and be curious are a good thing, but you don’t want to oversell it so people are thinking they are going to see Star Wars.”
What is being touted across social media is a “super blue blood moon.” A total lunar eclipse is sometimes referred to as a blood moon because it can take on a red hue as the light from the sun passes through Earth’s atmosphere.
“This uses up all the superlatives; super moon, blue moon, lunar eclipse. What else is there?” said Florida Atlantic University astronomy professor Eric Vandernoot. “I don’t like the term blood moon, because it’s never blood red, it’s more peachy, and looks like a big peach in the sky.”
Whether red or peach, the total lunar eclipse won’t be visible in South Florida because it happens near sunrise for the East Coast when the moon has already dipped below the horizon. But Beatty said a partial lunar eclipse should be visible for those with a clear view west. At 6:20 a.m., the first shadowy bite out of the moon will begin, followed by a partial eclipse at 6:48 a.m.
For South Florida luna lovers who don’t want to miss out entirely, a good moon view may happen at moonrise Tuesday over the ocean at 5:18 p.m., or Wednesday’s moonrise at 6:25 p.m.
The eclipse will be fully visible in western North America across the Pacific to Eastern Asia, with a partial eclipse beginning at 3:48 a.m. Pacific Standard Time, followed by the total eclipse at 4:52 a.m. It is the first total eclipse of the moon since September 2015.
NASA will televise the eclipse live on its website beginning at 5:30 a.m. Wednesday with views from telescopes in California and the University of Arizona’s Mt. Lemmon SkyCenter observatory.
“The farther west you are, the higher the moon will be in the predawn sky when the eclipse starts — and the more of it you’ll see,” said Diana Hannikainen, an observing editor for Sky & Telescope.
A total lunar eclipse during a blue moon that is in perigee last happened worldwide on Dec. 30, 1982, Beatty said. It was not visible in the U.S.
The next meet-up of a blue moon, super moon and total lunar eclipse is Jan. 31, 2037.
“Even in Palm Beach where you probably have bad light pollution and don’t see many stars, you can certainly see the moon,” Beatty said.
Beatty is also impressed that this year will have two blue moons, the one on Wednesday and one on March 31, while February gets no full moon. An older definition from the Maine Farmer’s Almanac of blue moon is the third full moon in a season, but a Sky & Telescope writer misunderstood the definition in 1946 and described a blue moon as the second full moon in a month, according to Beatty.
The definition got picked up as a question in the Trivial Pursuit board game, and was used in a popular 1980 astronomy radio program.
“It took on a life of its own from there,” Beatty said. “Most of me does wince about the nicknames but part of me doesn’t because it’s about getting people to go outside and look up at night.”