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A subtle lunar eclipse on March 23

Observant people in North America and the Pacific will see a very, very subtle partial penumbral eclipse of the moon on the morning of March 23, 2016. The blazing planet Jupiter will be nearby. Western North America and Hawaii have the eclipse taking place in the nighttime sky from start to finish.

Other regions having all or part of the eclipse going on while the moon is above the horizon include much of Asia, Australia, New Zealand, much of South America, the Caribbean, Indian Ocean, the Arctic and Antarctica. If you live in Asia, Australia or New Zealand, the eclipse happens on the evening of March 23.

The moon will look plenty full as it lights up the eastern sky at nightfall March 22, but it’ll actually be a waxing gibbous moon. The moon turns precisely full on March 23 at 12:01 Universal Time. At U.S. time zones, that translates to 8:01 a.m. EDT, 7:01 a.m. CDT, 6:01 a.m. MDT and 5:01 a.m. PDT.

If you’re on the nighttime side of the world when the moon turns full, you might notice the very faint penumbral shadow of the Earth falling on the southern portion of the moon’s disk, as illustrated below.

From all time zones in contiguous North America, you’ll want to look for the eclipse shortly before dawn breaks.

Read more: What is a penumbral eclipse of the moon?.

The full moon moves from west to east through the faint penumbral shadow, swinging north of Earth's dark cone-shaped umbra.

The full moon moves from west to east through the faint penumbral shadow, swinging north of Earth’s dark cone-shaped umbra.

We give you fair warning, however. You may not detect any shadow on the moon, even if you’re viewing it at the moment of its deepest eclipse on March 23 at 11:47 Universal Time (4:47 a.m. Pacific Daylight Time).

That’s because a penumbral eclipse is a very subtle kind of eclipse.

Observant people will notice the shadow!

Others will stand looking at it and say they can’t see it at all.

This wonderful diagram is from Larry Koehn at shadowandsubstance.com.  Go there to see what else is offered!

This wonderful diagram is from Larry Koehn at shadowandsubstance.com. Go there to see what else is offered!

This diagram is from timeanddate.com  That link has more eclipse info.

This diagram is from timeanddate.com Click that link for more eclipse info.

From around the word, look for the moon and Venus in the eastern sky as darkness falls.

From around the word on the night of March 22-23, 2016, look for the blazing planet Jupiter near the moon.

View larger. | Left, an ordinary full moon with no eclipse.  Right, full moon in penumbral eclipse on November 20, 2002.  Master eclipse photographer Fred Espenak took this photo when the moon was 88.9%  immersed in Earth's penumbral shadow.

View larger. | Left, an ordinary full moon with no eclipse. Right, full moon in penumbral eclipse on November 20, 2002. Master eclipse photographer Fred Espenak took this photo when the moon was 88.9% immersed in Earth’s penumbral shadow. There’s no dark bite taken out of the moon. A penumbral eclipse creates only a dark shading on the moon’s face.

The eclipse on March 23, 2016, would be considerably more spectacular from the moon. Someone standing inside the Earth's penumbral shadow on the moon would see a partial solar eclipse, with our planet Earth taking a bite out of the sun's disk!

The eclipse on March 23, 2016, would be considerably more spectacular from the moon. Someone standing inside the Earth’s penumbral shadow on the moon would see a partial solar eclipse, with our planet Earth taking a bite out of the sun’s disk!

In a lunar eclipse, Earth's shadow falls on the moon.  If the moon passes through the dark central shadow of Earth - the umbra - a partial or total lunar eclipse takes place.  If the moon only passes through the outer part of the shadow (the penumbra), a subtle penumbral eclipse occurs.  Diagram via Fred Espenak's Lunar Eclipses for Beginners.

In a lunar eclipse, Earth’s shadow falls on the moon. If the moon passes through the dark central shadow of Earth – the umbra – a partial or total lunar eclipse takes place. If the moon only passes through the outer part of the shadow (the penumbra), a subtle penumbral eclipse occurs. Diagram via Fred Espenak’s Lunar Eclipses for Beginners.

We recently had a lunar tetrad – four total lunar eclipses in a row, separated by six lunar months (full moons) – during the years 2014-2015. Now, we’re having four lunar eclipses in a row that are not total lunar eclipses.

Although every year has at least two lunar eclipses, both of this year’s lunar eclipses are penumbral.

Next year, in 2017, the first of two lunar eclipses will be penumbral and the second partial. The next total lunar eclipse won’t be until the Blue Moon of January 31, 2018.

What is a Blood Moon?

What is a Blue Moon?

In the 21st century (2001 to 2100), we have a total of 8 lunar tetrads – four total lunar eclipses in a row, with no partial or penumbral lunar eclipses in between. After each lunar tetrad, there are at least 4 lunar eclipses in a row that AREN’T total, so I guess we’re now paying our dues.

It is also possible to have four penumbral lunar eclipses in a row, with no other kind of lunar eclipse in between. This last happened in the years 2001-2002, and will happen next in the years 2030-2031. And, in 2085, we find four penumbral lunar eclipses happening in one calendar year.

Day and night sides of Earth at the instant of the March 2016 full moon (2016 March 23 at 12:01 Universal Time).

Day and night sides of Earth at the instant of the March 2016 full moon (2016 March 23 at 12:01 Universal Time).

Bottom line: Although every year has at least two lunar eclipses, both lunar eclipses in 2016 are faint penumbral eclipses. The penumbral eclipse of March 23, 2016 – visible in its entirety from western North America – will be very subtle. Other regions seeing all or part of the eclipse include much of Asia, Australia, much of South America, the Atlantic, Indian Ocean, the Arctic and Antarctica.

Bruce McClure

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