How to See the Brightest Supermoon of 2017

Our cosmic companion is about to put on its best show of the year—here’s how to watch.

By Andrew Fazekas
Published 21 Nov 2017, 21:29 GMT
Photograph by Adam Cairns, The Columbus Dispatch, Associated Press

On the night of the 3rd December , sky-watchers around the world will get a chance to revel under the first—and last—full supermoon of the year.

A supermoon is the popular term for a full or new moon that coincides with the lunar orb making an especially close approach to Earth. The moon’s orbit around Earth is not a perfect circle but is somewhat elongated. That means the moon changes its distance to Earth by a few thousand miles over time, reaching a closest point (perigee) and a farthest point (apogee) in any given month.

What is a Supermoon?
What is a supermoon? Find out what makes the moon appear extra big and bright, how it effects the tides, and how the phenomenon got its name.

Technically, this will be the fourth supermoon of the year, but it’s the only one we’ve been able to see with naked eyes. That’s because the other three supermoons of 2017 coincided with new moons, when the lunar disk shows a totally darkened face. (Find out what a “black moon” is and when to see one.)

The December full moon officially occurs at 3:47pm (Greenwich Mean Time) on the 3rd. Less than a day later, the lunar orb will make its closest approach to Earth for the month, coming within 222,443 miles of our planet at 9 a.m. ET (9:00 UT) on the 4th. That means the moon on the night of the 3rd December will appear about seven percent larger and 16 percent brighter than usual.

Don’t be surprised if you’re having a tough time spotting the difference, though. The moon is so far away that these subtle changes can be tough to detect with the naked eye.

The best time to enjoy the view will be as the full moon rises just minutes after local sunset, when an optical effect called the moon illusion will make the supermoon appear much bigger and brighter than it will once it’s high in the sky. (Get our tips and trick for how to photograph a supermoon.)

Through the overnight hours, the moon will sit within the bright constellation Taurus, the bull. By covering the lunar disk with your thumb, you can look for the nearby orange star Aldebaran, a stellar giant 65 light-years away that marks the eye of this mythical bull.

Lucky sky-watchers in northern Alaska, Canada, Russia, and wide parts of China will get to see the moon briefly slide in front of this star.

While there is no need for any special instruments to enjoy the sky show, observers using cameras with telephoto lenses, binoculars, or telescopes can use the opportunity to get enhanced views of the lunar surface.

If your night skies end up cloudy, you can still catch the supermoon online with a free webcast from the Virtual Telescope Project starting at 4pm on 3rd December. Astronomers will provide real-time images of our beautiful satellite as it rises above the legendary monuments of Rome in Italy.

And don’t worry if you miss this month’s supermoon, because you’ll get two more chances early in 2018. The full moon on 2nd January and another on 31st January 31 will also be supermoons.

Clear skies!

Andrew Fazekas, the Night Sky Guy, is the author of Star Trek: The Official Guide to Our Universe and host of NG Live! Mankind to Mars presentations.

Read More

You might also like

Environment and Conservation
What is the Autumn equinox? Here's what you need to know.
NASA sent a map to space to help aliens find Earth. Now it needs an update.
Buzz Aldrin Hates Being Called the Second Man on the Moon
A Supermoon Will Eclipse the Sun on Friday the 13th
Naked-Eye Asteroid and More Can't-Miss Sky Events in June

Explore Nat Geo

  • Animals
  • Environment
  • History & Culture
  • Science
  • Travel
  • Photography
  • Space
  • Adventure
  • Video

About us


  • Magazines
  • Newsletter
  • Disney+

Follow us

Copyright © 1996-2015 National Geographic Society. Copyright © 2015-2021 National Geographic Partners, LLC. All rights reserved