Friday morning’s partial lunar eclipse will flirt with with totality, as the longest for more than a century.

If you’re like us, we never miss a chance to catch a lunar eclipse, be it penumbral, partial or total. Lunar eclipses are a great time to catch the surety of the clockwork Universe at its best, as the Moon slides into and then exits the Earth’s shadow.

First the bad news: Friday morning’s eclipse in the early hours of November 19th isn’t completely total. However, the good news is that at its maximum around 9:04 Universal Time (UT)/4:04 AM Eastern Time (EST) the eclipse narrowly misses totality, at 97.5% partial.

Lunar eclipses occur at Full Moon, when the intersecting node of the Moon’s orbit along the ecliptic plane falls near the Earth’s shadow cast back into space. The Moon’s orbit is tilted about 5 degrees relative to the ecliptic, otherwise, we’d see lunar and solar eclipses every lunation.

Times and Visibility

Most of North America and the Pacific will see the eclipse in its entirety. Eastern North America, South America, the United Kingdom and Scandinavia will see the eclipse in progress at sunrise, while Australia and the Far East will see the eclipse in underway at sunset; only Europe, Africa and the mid-East will sit this one out. The Moon is in the astronomical constellation of Taurus the Bull when the eclipse occurs.

There are also some noteworthy facets of Friday’s eclipse: This is the deepest partial lunar eclipse that misses totality until the 98.65% eclipse on November 20th, 2086, and since the 99.6% eclipse of October 13th, 1856. This week’s eclipse is also the longest partial eclipse of the 21st century at 3 hours, 28 minutes and 23 seconds in duration, the longest since February 18th, 1440 (at 3 hours 28 minutes and 46 seconds) and until February 8th, 2669 (at 3 hours, 30 minutes and 2 seconds), which is also the longest of 5 millennium span of eclipses from 2,000 BC to 3,000 AD.

The path of the Moon (top) through the Earth’s shadow this coming Friday, with visibility prospects worldwide (bottom). Credit: NASA/GSFC/F. Espenak.

Here are the key times for Friday’s partial lunar eclipse:

Penumbral begins: 6:02 UT/1:02 AM EST

Umbral begins: 7:19 UT/2:19 AM EST

Mid-Eclipse: 9:04 UT/4:04 AM EST

Umbral ends: 10:47 UT/5:47 AM EST

Penumbral ends: 12:04 UT/7:04 AM EST

Penumbral duration: 6 hours, 1 minute and 29 seconds

Umbral duration: 3 hours, 28 minutes and 23 seconds

Flirting with totality: the phases of a lunar eclipse. Credit: Dave Dickinson.

Take a good look at the Moon at mid-eclipse Friday morning and ask yourself: does it look total or partial to you? Would you know it was ‘just a deep partial eclipse’ if you didn’t know better? We had a slightly similar situation during the 2015 tetrad of lunar eclipses, with a totality of just under five minutes in duration during the April 4th, 2015 lunar eclipse. Many observers noted that—to their eyes—the outer limb of the Moon never seemed to go completely dark.

Tales of the Saros

This particular eclipse is member 46 of the 72 eclipses in saros series 126. if you saw the brief (22 minutes total) eclipse on November 9th 2003, then you caught the final total eclipse for this saros series, which started all the way back on July 18th, 1228, and spawned its first total lunar eclipse on June 19th, 1769…the eclipses for this series are now partial only from here
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