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(near) Total Eclipse of the Moon 11/18/21 - long event


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Visible from all of N America.  Starts at 1:19 CT near full at 3:30 CT (So really it is tomorrow morning)


Why is this eclipse so long?

This is a long eclipse for two main reasons: 1) The Moon’s orbital speed and 2) The near-totality of the eclipse.

First, the Moon’s orbit around the Earth is not a perfect circle, and the Earth is off-center within the orbit so sometimes the Moon is closer to the Earth and sometimes it is farther away. This change in distance impacts the Moon’s orbital speed. Closer to the Earth, the Moon moves faster, while further away, it travels more slowly. Right now, the Moon is near its farthest point in its orbit around the Earth and thus, moves slowly through Earth’s shadow.

Second, since this eclipse is almost-total, the Moon spends a longer amount of time in the Earth’s umbra than it would in a ‘more-partial’ eclipse.


Edited by TexasEd
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