Lunar and Planetary Institute

Super Lunar Eclipse on January 31

January 30, 2018


Photo courtesy of NASA’s Space Place

By Christine Shupla and Carolyn Ng
A total lunar eclipse can be an eerie sight, as the moon grows dark and red. While each year features at least two lunar eclipses, many are partial or penumbral eclipses in which the moon only grows slightly darker. The early morning of January 31 marks the first total lunar eclipse visible in the United States since 2015; people across the central and western United States who rise before sunrise that morning will be able to see a total lunar eclipse before the moon sets in the west. Those in the eastern US can still see a partial lunar eclipse, but the moon will set before totality.

Lunar eclipses only happen during the full moon, as the moon moves into Earth’s shadow. January 31 happens to be the second full moon this month, making this a “blue moon,” in spite of its color. There are several definitions of a “blue moon”; the modern definition is the second full moon in a month, which happens on average every two-and-a-half years.

The moon’s orbit around Earth is not perfectly circular; sometimes the moon is farther or closer in its orbit. A popular term for when the full moon happens to also be at the closest point in its orbit is a “supermoon.” Since the moon’s closest point in its orbit will be January 30, the full moon on January 31 also qualifies as a supermoon!

There are a variety of fun activities you can do:

If you miss this lunar eclipse, you will just need to wait a year; the next total lunar eclipse visible in the US will be on January 21, 2019.

Christine Shupla leads the Lunar and Planetary Institute’s professional and materials development for a variety of audiences, and serves as NASA’s liaison to the American Camp Association.

Carolyn Ng is the Informal Education Lead for the NASA Space Science Education Consortium at NASA Goddard Space Flight Center.

For more information, visit:
Lunar Eclipses
Moon Viewing Ideas
The Supermoon
Jan. 31 Interactive Eclipse Viewer
Blue Moons






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