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October 'Supermoon' to Light Up Weekend Sky Across Maryland

Astronomers say the moon will be large and bright Oct. 15 and 16. Will the skies clear for good views in Maryland?

Whether you call the big, orange moon on display Sunday, Oct. 16, a supermoon or a hunter's moon, the bigger question for Maryland sky-watchers may be: Will we see it?

We'll be under clear skies Saturday night, with only a few clouds on Sunday night, according to the latest forecast from the National Weather Service. So go outside after 7 p.m. either night and you should catch some glimpses of the supermoon. The October full moon, which is also a hunter’s moon, is the first of three supermoons that will close out the year, with the trifecta continuing in November and December.

The moon will be especially bright because it’s near perigee. What’s that, you who slacked in science class, ask? “Supermoon” is the unofficial term for “perigee,” when a full moon coincides with the moon’s closest approach to Earth in its oval-shaped orbit, making it appear 14 percent bigger in the night sky and often taking on an orange hue.

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Are supermoons just hype? Yes and no. Supermoons aren’t really larger, but they only appear so because the moon is so close to the Earth. But, Earthsky.org says, “they can cause real physical effects, such as larger-than-usual tides.”

Also, the orange color of the moon near the horizon “is a true physical effect.”

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“It stems from the fact that — when you look toward the horizon — you are looking through a greater thickness of Earth’s atmosphere than when you gaze up and overhead. The atmosphere scatters blue light – that’s why the sky looks blue,” Earthsky.org says. The greater thickness of atmosphere in the direction of a horizon scatters blue light most effectively, but it lets red light pass through to your eyes. So a moon near the horizon takes on a yellow or orange or reddish hue.”

October’s supermoon is a sort of warm-up event for the Nov. 14 supermoon, which will be the closest to the Earth of any supermoon so far in the 21st century. Earthysky.org says a moon won’t be as close to Earth again until Nov. 25, 2034, and that in the Americas, the best night to view it may be Nov. 13 instead of Nov. 14.

Astrophysicist Fred Espenak, a NASA scientist emeritus, lists the Oct. 16, Nov. 14 and Dec. 13 full moons as supermoons, and also includes the January 2017 full moon on the list. Their disagreement comes from ambiguity on how “90 percent of perigee” is measured.

Supermoons during the winter months tend to look larger than Supermoons that occur during the rest of the year in the Northern Hemisphere. At this time of the year, the Earth is closer to the Sun. Because of this, the Sun's gravity pulls the Moon closer to Earth, making any winter Super Full Moons look bigger than summer Perigee Moons.

— Includes reporting by Patch Editor Beth Dalbey
»Photo by Derek Keats via Flickr Commons

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