The full moon is bigger and brighter than average this weekend, all over the world, but there's a special treat in store for New Yorkers: the combination of a Supermoon with the sunset phenomenon known as Manhattanhenge. Call it "Moonhattanhenge."
"You don't always get this kind of thing," Jackie Faherty, an astronomer at the American Museum of Natural History in New York, told NBC News. "Two for the price of one!"
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In May and July of each year, the celestial arrangements are such that the sun sets precisely in alignment with Manhattan's main street grid, creating a photo op for observers who point their cameras westward at just the right time. Weather permitting, New Yorkers can see the full disk of the sun sitting on the horizon, in the space between the skyscrapers, at 8:24 p.m. ET Friday.
On Saturday, half of the sun's disk will be framed by Manhattan's concrete canyons at 8:25 p.m. ET. Check out AMNH's online guide for additional advice on where to go and when to show up.
This year is super-special because Manhattanhenge takes place during the moon's full phase. If you show up early on Friday night and look to the east, you can see the full moon rising between the skyscrapers a few minutes after 8 p.m. ET, Faherty said. On Saturday, the timing is even closer: The full moon is due to rise at 8:27 p.m. and become visible in the gap between the skyscrapers at 9:16 p.m.
"You can just turn around and look the other way, and it'll be there," Faherty said. However, you'll want to make sure you're stationed on a street that has an unobstructed view to the eastern as well as the western horizon. Faherty says 14th, 34th, 23rd and 42nd streets will work.
May's Manhattanhenge opportunity was mostly clouded out, but the weather looks more promising this weekend. "I think we're going to have a good sunset," Faherty said. She's due to lead a presentation about the phenomenon at the museum, starting at 7 p.m. ET, then take folks outside to have a look at 7:50 p.m. It's a good idea to get to your viewing site early, no matter where you're headed, because there could be a crowd.
Season of the Supermoon?
Now, as for that full moon: This is the first of three full moons this summer that are occurring when the moon is closer to Earth than average. That's led some observers to call this the season of the Supermoon — a term that Geoff Chester, an astronomer at the U.S. Naval Observatory, wishes would go away.
Chester acknowledges that a perigee full moon can be as much as 14 percent bigger than a full moon at its maximum distance from Earth. He admits that "it might be possible for a skilled observer to notice the difference in the apparent size." And he understands that calling the phenomenon a "Supermoon" can be a consciousness-raiser for people who don't make a habit of observing the night sky.
"But this idea that there's something inherently cosmic about it — that's not the kind of thing I'd want to see promulgated," he told NBC News.
For the full story about the full moon — including just how "Super" this summer's sightings will be — check out this Supermoon guide. And if you snap a great picture of the full moon, or Manhattanhenge, please share it with us via Twitter or Instagram by using the hashtag #NBCSupermoon or #NBCHenge. You can also send us your pictures via our FirstPerson photo-upload website.
First published July 11 2014, 3:40 PM