The first of four consecutive total lunar eclipses takes place on the night of April 14–15, with excellent viewing prospects all across the U.S. and Canada.

From Simi Valley, California, December 2011's totally eclipsed Moon hung just a few degrees above the western horizon. The southern half (lower left) of the disk, nearest the umbra's outer edge,  is relatively bright. S&T: J. Kelly Beatty
From Simi Valley, California, December 2011's totally eclipsed Moon hung just a few degrees above the western horizon. The southern half (lower left) of the disk, nearest the umbra's outer edge, is relatively bright.
S&T: J. Kelly Beatty

Update: Watch this morning's Today Show to see Alan MacRobert talk about the total lunar eclipse and why it's an excellent opportunity to turn our eyes (and those of our friends and neighbors) to the sky.

North America hasn't had a total eclipse of the Moon since 2011. But this long dry spell will break in the early morning hours of April 15th (beginning late on April 14th for the West Coast), when the full Moon passes through the umbra — the dark inner core of Earth's shadow.

The diagram and timetable below tell what to expect and when if you live in North America. The eclipse will also be visible from Central and South America and much of the Pacific. In eastern Australia the Moon doesn't rise until the total eclipse is already underway on the evening of the 15th.

Update: Is it cloudy? Are you on the wrong side of the world? Watch live online, courtesy of Virtual Observatory.

The Stages of a Lunar Eclipse

A total lunar eclipse has five stages, with different things to watch at each:

Penumbral eclipse: Shading starts to occur when the Moon's leading edge enters Earth's penumbra, the outer portion of its shadow. But initially the effect is weak — you won't start to see a dusky fringe along the Moon's leading limb (celestial east) until the disk intrudes about halfway across the penumbra. As the Moon glides deeper in, the shading becomes much more obvious.

Partial eclipse: More dramatic is the Moon's entrance into the umbra, where no direct sunlight reaches the lunar surface. Few sights in astronomy are more eerie and impressive than watching this red-black shadow creeping, minute by minute, across the bright lunar landscape, slowly engulfing one crater after another. If you're so inclined, there's scientific value in carefully timing these crater crossings.

As more of the Moon slides into the umbra, a second, deeper night is falling around you as more stars come out in what had been a full-Moon-washed sky. An hour or so into partial eclipse, only a final bright sliver remains outside the umbra and the rest of the Moon is already showing an eerie reddish glow.

Total eclipse: From the Moon's perspective, the Sun remains completely hidden for 1 hour 18 minutes. From Earth's perspective, the lunar disk isn't completely blacked out but instead remains dimly lit by a deep orange or red glow. Why so?

Our atmosphere scatters and refracts (bends) sunlight that grazes the rim of our globe, so that red glow comes from all the sunrises and sunsets around Earth's terminator at the moment. If you were an astronaut standing on the Moon, you'd see Earth ringed with a thin, brilliant band of sunset- and sunrise-colored light. On rare occasions the eclipsed Moon does go black. Other times it appears as bright and coppery as a new penny. Sometimes it turns brown like chocolate, or as dark red as dried blood.

Two factors affect an eclipse's color and brightness. The first is simply how deeply the Moon goes into the umbra — because the umbra's center is much darker than its outer edge. The second is the state of Earth's atmosphere all around the terminator. If the air is very clear, the eclipse is bright; if it's mostly cloudy (or polluted with volcanic ash from a major eruption), the eclipse will be dark red, ashen gray, or almost black.

Aligning his camera on the same star for nine successive exposures, Sky & Telescope contributing photographer Akira Fujii captured this record of the Moon’s progress dead center through the Earth’s shadow in July 2000. Akira Fujii
Aligning his camera on the same star for nine successive exposures, Sky & Telescope contributing photographer Akira Fujii captured this record of the Moon’s progress dead center through the Earth’s shadow in July 2000.
Akira Fujii

Adding to the late-night spectacle will be the bright star Spica shining only about 1° or 2° from the Moon, and brilliant Mars about 9° to the west.

Partial eclipse: Totality ends once the Moon's leading limb peeks back into direct sunlight, and after that events unfold in reverse order. If you're using binoculars or a small telescope to view the eclipse, watch as lunar features slide back into full view.

Penumbral eclipse: When all of the Moon has escaped the umbra, only the last, penumbral shading is left. This final duskiness gradually fades away, leaving the full Moon shining as bright and white as ever. Notably, of the three lunar eclipses in 2013, two were penumbra-only events.

Total eclipse of the Moon, April 14-15, 2014*
Eclipse event UT  EDT CDT MDT PDT
Penumbra first visible? 5:20 1:20 a.m. 12:20 a.m 11:20 p.m. 10:20 p.m.
Partial eclipse begins 5:58 1:58 a.m. 12:58 a.m. 11:58 p.m. 10:58 p.m.
Total eclipse begins 7:07 3:07 a.m. 2:07 a.m. 1:07 a.m. 12:07 a.m.
Mid-eclipse 7:46 3:46 a.m. 2:46 a.m 1:46 a.m. 12:46 a.m.
Total eclipse ends 8:25 4:25 a.m. 3:25 a.m. 2:25 a.m. 1:25 a.m.
Partial eclipse ends 9:33 5:33 a.m. 4:33 a.m. 3:33 a.m. 2:33 a.m.
Penumbra last visible? 10:10 5:10 a.m. 4:10 a.m. 3:10 a.m.

* Note: all a.m. times are on April 15th; all p.m. times are on April 14th

If it's cloudy from your location in North America, you won't have another long wait for the next total lunar eclipse. The next one comes on the morning of October 8th for the whole continent except the farthest northeast. In fact, April's event is the first of four consecutive total lunar eclipses in 2014–15! Such eclipse tetrads are not common — the last one occurred a decade ago, but the next won't begin until 2032.


Alan MacRobert made his first crater timings during another mid-April lunar eclipse next to Spica: on April 12–13, 1968.

Comments


Image of John E

John E

April 4, 2014 at 4:17 pm

This post describes what the Earth would look like to an observer on the Moon during a lunar eclipse. ("...Earth ringed with a thin, brilliant band of sunset- and sunrise-colored light.") Are any of the spacecraft that are orbiting the Moon equipped to photograph this? I guess LADEE has no camera. LRO? Any others? In absence of real photos, are there any simulations?

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John E.

April 7, 2014 at 11:30 am

Regarding the above question, I got my answer from the Astronomy Picture of the Day for April 7. (http://apod.nasa.gov/apod/ap140407.html) It seems a few shots of the Earth eclipsing the Sun have been taken and that more are planned for the April 14/15 eclipse.

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Aqua4U

April 12, 2014 at 3:28 pm

Given the above times and locations, the fullest moon and greatest extent of the eclipse puts Luna somewhere over the Southwestern United States? or along a line drawn south of that approx. longitude (Noting here from the above, the total eclipse will be at 12:07 AM PST). I know that previous studies have shown there is no correlation or hard evidence there is any association with full or new moons at any distance, and earthquake events. But just for giggles and grins... it might be interesting to keep an eye on this page? http://earthquakes.tafoni.net/

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Robert

April 14, 2014 at 10:40 pm

Alan -- Thanks for not using the phrase "blood moon." This apocalyptic sounding phrase has swept through the media. Like the use of "supermoon" for a full moon near perigee, we may be stuck with this stupid phrase for a long time to come. Today I heard a radio announcer say that tonight we'll have a total lunar eclipse and a blood moon, as though they are distinct phenomena.

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NS

April 15, 2014 at 3:57 am

I'm near Honolulu, in partly cloudy conditions. Not observing continuously, but caught the initial partial eclipse a couple of times through holes in the clouds, had another clear patch right at the beginning of totality, and just had a nice view of the mid-eclipse. Reddish (but not "blood red").

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