An Almost-Total Partial Lunar Eclipse

Tonight, half of the world—including the U.S.—will be treated to a partial lunar eclipse that is so deep that it is almost total. At mid-eclipse, which occurs at 3:02:56 a.m. CST, only about 45 arcseconds of the Moon’s south-southeastern limb (as seen in the sky) will extend beyond the Earth’s umbral shadow into the penumbral shadow. This is extraordinary. Tonight’s eclipse will be the longest partial lunar eclipse since February 18, 1440, and a partial lunar eclipse this long won’t occur again until February 8, 2669.

Here is the time for each important event during the eclipse, given in Central Standard Time, and—allowing for time zone corrections—the same everywhere the eclipse is visible, plus local circumstances for Dodgeville, Wisconsin.

Time (CST)EventAltitude
12:02:09 a.m.Penumbral Eclipse Begins65˚
1:18:43 a.m.Partial Eclipse Begins58˚
3:02:56 a.m.Greatest Eclipse42˚
4:47:07 a.m.Partial Eclipse Ends24˚
5:19:03 a.m.Astronomical Twilight Begins18˚
5:52:45 a.m.Nautical Twilight Begins12˚
6:03:44 a.m.Penumbral Eclipse Ends10˚
Partial Lunar Eclipse of Friday, November 19, 2021

The Moon is in the constellation Taurus for this eclipse, and you’ll enjoy seeing the Pleiades star cluster nearby become increasingly visible as the eclipse progresses towards maximum. Enjoy!

Animation courtesy of Shadow & Substance

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