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The Only Supermoon of 2017 Is Coming. Here’s When to View It

2 minute read

This weekend, sky-watchers can look forward to a phenomenon that hasn’t yet graced the skies this year: a supermoon. Before you dig out your telescope, however, here’s what you need to know about the only supermoon of 2017 — and the best time to view it.

What is a supermoon?

The moon makes an elliptical orbit around Earth once every 27 days, while a full moon happens once every 29.5 days. When the moon is full during the portion of its orbit that brings it closest to Earth, Space.com reports, a supermoon occurs. Supermoons look a bit brighter and closer to Earth than average full moons, though it can be hard to spot the differences without a telescope. Supermoons are sometimes called cold moons, according to National Geographic.

When’s the best time to view the supermoon?

The only supermoon of the year is slated for Dec. 3, 2017, at precisely 15:47 UTC, according to EarthSky.org. After that, there will be supermoons on Jan. 2 and Jan. 31, 2018. Time your viewing for just after local sunset, National Geographic suggests, when the “moon illusion” will make the orb look especially large and vibrant.

How can I see the supermoon?

While you likely won’t be blown away if you look for the supermoon with your naked eye, National Geographic says you may see enhanced effects using cameras with telephoto lenses, binoculars or telescopes. You can also watch a livestream from the Virtual Telescope Project.

What’s the difference between a supermoon and a Blue Moon?

A Blue Moon refers to the second full moon in a calendar month — which is rare, since full moons occur every 29.5 days, according to NASA. A Blue Moon can be a supermoon, just like any other full moon. In fact, the supermoon slated for Jan. 31, 2018, will be both, making it a Super Blue Moon.

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Write to Jamie Ducharme at jamie.ducharme@time.com