The longest lunar eclipse this century will happen early Friday morning. Here's how to see it.

The moon enters the maximum eclipse in Glastonbury, England, on September 28, 2015.Matt Cardy/Getty Images

  • A near-total lunar eclipse will occur early Friday morning, with prime visibility in North America.

  • It will last 3 hours and 28 minutes — the longest partial lunar eclipse this century, NASA predicts.

  • Here's how to see the rare event, when up to 97% of the moon will look red.

The longest lunar eclipse of this century is coming this week.

During the early hours of Friday morning, Earth will pass between the sun and moon, casting a shadow over the latter. The eclipse will peak just after 4 a.m. Eastern Time, when our planet will hide 97% of the full moon from the sun's light, giving the moon a reddish hue.

According to NASA, the partial lunar eclipse will last 3 hours, 28 minutes, and 23 seconds — longer than any other eclipse between 2001 and 2100.

Here's how and when to catch the rare celestial event.

People in North America can watch the entire spectacle

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A lunar eclipse as seen from Santa Monica, California, on October 8, 2014.Lucy Nicholson/Reuters

Lunar eclipses aren't visible worldwide — only in places where the moon is above the horizon.

For the upcoming eclipse, sky watchers in North America have the best seats in the house. People in all 50 US states, Canada, and Mexico can watch the full event.

You won't need a telescope or binoculars — simply go outside and look up at the sky any time between 2:19 a.m. and 5:47 a.m Eastern Time on Friday.

Or if you don't want to head into the chilly morning air, catch a live stream of the event here.

Folks in South America and western Europe will see most of the eclipse, though the moon will set before it ends. People in western Asia and Oceania will miss the earlier part of the event, as the moon will not have risen yet. Those living in Africa and the Middle East won't see any of the spectacle.

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A map of locations where the partial lunar eclipse will be visible on November 19.NASA

If you miss the eclipse, don't fret. After this, NASA predicts another 179 eclipses in the next eight decades, with an average of two per year. The next eclipse will happen on May 16, 2022.

How a lunar eclipse works — and why it turns the moon red

Typically, the moon's white-grey face is illuminated by sunlight reflecting off its surface. But during a lunar eclipse, the moon, sun, and Earth briefly align so that our planet blocks sunlight from reaching the moon.

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A diagram of the Earth, moon, and sun during a total lunar eclipse.Shayanne Gal/Business Insider

A total lunar eclipse occurs when 100% of the moon is obscured by the Earth's cone-shaped shadow, known as the umbra. During a total eclipse, or near-total eclipse like this month's event, the lunar surface takes on a bloody visage.

We have oxygen and nitrogen particles in Earth's atmosphere to thank for that light show. They're better at scattering certain shorter wavelengths of light, like blue or violet, so colors with longer wavelengths — like red, orange, or yellow — still linger. When the moon sits in Earth's shadow, those reddish colors dominate what you see.

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