GRAND RAPIDS, Mich. (WOOD) — An astronomical event will take place this week, and all of North America will have a chance to see it. 

A partial lunar eclipse, which will occur during the November full moon, will be visible in the pre-dawn hours Friday. It will also be the longest in centuries.

A partial lunar eclipse happens when the Earth passes between the sun and the moon, casting a shadow on the moon. If the entire moon is in Earth’s umbral shadow, or the darkest part of the shadow, it is a total lunar eclipse. If only part of the moon is in Earth’s umbral shadow, it is a partial lunar eclipse. 

Friday’s lunar eclipse will almost be a total lunar eclipse, but not quite. About 97% of the moon will be in the earth’s shadow. This means most of the moon will take on the dimmed, reddish look of a lunar eclipse, while a tiny sliver will still look normal. 

The November full moon is often called the beaver moon — so-called because it appears when beavers begin to shelter in their lodges ahead of winter — will be in Earth’s shadow for several hours, and it will be visible for all of North America if cloud conditions allow.

In total, the partial lunar eclipse is expected to last three hours and 28 minutes, making it the longest one not just of the 21st century, but in more than 580 years, NASA records show.

“Partial lunar eclipses might not be quite as spectacular as total lunar eclipses – where the Moon is completely covered in Earth’s shadow – but they occur more frequently,” NASA stated on its website. “And that just means more opportunities to witness little changes in our solar system that sometimes occur right before our eyes.”

The eclipse will be visible in North and South America, the Pacific Region, Australia and Eastern Asia, so long as weather permits.

Unlike a solar eclipse, a lunar eclipse is safe to view with the naked eye. It also requires no special equipment to see it, though you could use binoculars or a small telescope to get a closer look.

Every year, there are two to five lunar eclipses, NASA says.