November 18, 2021

Partial Lunar Eclipse Friday Morning Turns Beaver Moon to a Blood Moon

Mary Apel

On November 19, 2021 (late evening of the 18th in some time zones), the Moon passes into the shadow of the Earth, creating a partial lunar eclipse so deep that it can reasonably be called almost total. Credit: NASA's Scientific Visualization Studio

The longest lunar eclipse in 580 years takes place tomorrow. It will be the second eclipse of the year.

What is it?

A partial lunar eclipse will take place in the wee hours of the morning Friday. According to, the magnitude of the eclipse is 0.974, which is why the eclipse is counted as partial rather than total, even though it will still resemble a total lunar eclipse.

A lunar eclipse occurs when the Sun, Earth, and Moon align so that the Moon passes into Earth’s shadow. In a total lunar eclipse, the entire Moon falls within the darkest part of Earth’s shadow, called the umbra. In this eclipse, up to 99.1% of the Moon’s disk will be within Earth’s umbra.

Blood Moon/ Beaver Moon

During a lunar eclipse the moon can appear to turn red as the sunlight reaching the moon passes through the earth’s atmosphere, earning itself the name “Blood Moon”. Typically November’s full moon is called the “Beaver Moon”. This nickname originated from Native American tribes who named moon phases based upon natural phenomenon occurring during the season. Allegedly the Beaver Moon is named so because the beavers would build their dams around this time of year to prepare for the coming winter. Other names for November’s full moon include Reed Moon, Mourning Moon, and Frost Moon.

How and when to see it

The best time to go out and see the eclipse will be right around its peak, on November 19th at 3:03 am locally. But the moon will begin to pass into the Earth’s shadow much earlier, around midnight Central Time. NPR reports that at 1:19 a.m., the moon will move into the umbra, the inner part of Earth’s shadow and begin to look like a chunk is missing from it. It will turn red around 2:45 a.m.

Watch the moon’s progression here:

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