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Lunar Eclipses

Lunar eclipse banner from May 2021 with no text
A telescopic visualization of the May 2021 total lunar eclipse. Credits: NASA’s Scientific Visualization Studio
Diagram of a lunar eclipse showing the position of the Moon, Earth, and Sun in a line not drawn to scale

What is a lunar eclipse?

During a lunar eclipse, the Earth blocks most of the sunlight that normally reaches the Moon. The Earth is between the Sun and the Moon.

This is different from a solar eclipse, when the Moon passes between the Sun and Earth and blocks all or part of the Sun.  In a solar eclipse, the Sun gets darker; in a lunar eclipse, the Moon gets darker.  Visit our solar eclipse page to learn more.

Upcoming lunar eclipses

Watch this NASA video to learn more about the different roles of the Moon in lunar and solar eclipses.

2021 Lunar Eclipses: May 25-26, 2021 and November 18-19, 2021

Who Can See It

Lots of people! People in the contiguous United States, Alaska, and Hawaii will see two lunar eclipse events this year—but not everyone will see a total lunar eclipse. lunar eclipse map May, 26 2021

Where and When Can You See It?

There are several websites to check to confirm if an when your location can view the total lunar eclipse on May 26th, 2021 and the partial lunar eclipse on Nov 19, 2021. 

May 25-26, 2021

November 18-19, 2021

Advice for Viewing

If skies are clear, the eclipse will be visible to the unaided eye. It is safe to view a lunar eclipse without any eye protection. 

More viewing tips an information about lunar eclipses from the May 2021 Skywatching Tips from NASA

Why Does the Moon Turn Red?

The Moon does not completely darken in the Earth's shadow during a lunar eclipse. Sunlight on the edges is scattered by the Earth's atmosphere, only allowing red light through to the Moon. This red light is reflected back to viewers on Earth who can see the lunar eclipse. 

Watch this NASA video to see why the Moon turns red during a lunar eclipse.

lunar eclipse season diagram

Additional Lunar Eclipse Resources

Observe the Moon activity page 1

Related NISE Network Moon Activities


close up of a lunar eclipse model

Related NASA Educator Guides and Activities


Compilation of Moon Resources including Artemis and Apollo Missions




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