More than two years have passed since most of North America saw a total lunar eclipse. So be sure to put a big circle on your calendar for Thursday, March 13.
The viewing circumstances for the total eclipse of the full moon that night will be as good as it can get for much of the United States and Canada. The western part of the continent has the best view, but the spectacle of the moon completely immersed in the Earth’s shadow will be readily visible from coast to coast.
The duration of totality will be longer than normal, lasting 1 hour and 6 minutes.
Moreover, the eclipse should arouse wide interest. Amateur groups should take this opportunity to alert schools and news media about their eclipse activities and amateur astronomy in general. On the West Coast, this event will occur during convenient mid-to-late evening hours. How about staging a neighborhood eclipse party?
Conversely, for those across the Atlantic, the eclipse will take place low in the western sky as the moon approaches its setting at dawn on Friday. In fact, across western portions of Europe and Africa, the moon will set while in total eclipse, while for those living in New Zealand, as well as those hearty denizens who occupy the Chukchi and Kamchatka Peninsulas of eastern Siberia, the moon will rise on their Friday evening, during totality.
No avid skywatcher ever misses a total eclipse of the moon. This celestial pageant is often more beautiful and interesting than one would think. During the time that the moon is entering into and later emerging from out of the Earth’s shadow, secondary phenomena may be overlooked.
To help prepare for the upcoming eclipse of March 13-14, Space.com’s Joe Rao — a veteran of 20 total lunar eclipses — has prepared a chronology, including some of the things you might expect to see. Probably not all of those mentioned will occur because no two eclipses are exactly the same.
But many will and those who know what to look for have a better chance of seeing it!
In the below timetable, local circumstances are provided for eight different time zones. All times are for p.m. on March 13, except when in italics, which corresponds to a.m. on March 14. When dashes are provided, it means that the moon is below the horizon.
|
Stage of eclipse |
GMT |
ADT |
EDT |
CDT |
MDT |
PDT |
AKDT |
HST |
|---|---|---|---|---|---|---|---|---|
|
1 |
3:57 |
12:57 |
11:57 |
10:57 |
9:57 |
8:57 |
7:57 |
—— |
|
2 |
4:47 |
1:47 |
12:47 |
11:47 |
10:47 |
9:47 |
8:47 |
6:47 |
|
3 |
5:09 |
2:09 |
1:09 |
12:09 |
11:09 |
10:09 |
9:09 |
7:09 |
|
4 |
6:04 |
3:04 |
2:04 |
1:04 |
12:04 |
11:04 |
10:04 |
8:04 |
|
5 |
6:22 |
3:22 |
2:22 |
1:22 |
12:22 |
11:22 |
10:22 |
8:22 |
|
6 |
6:26 |
3:26 |
2:26 |
1:26 |
12:26 |
11:26 |
10:26 |
8:26 |
|
7 |
—— |
3:58 |
2:58 |
1:58 |
12:58 |
11:58 |
10:58 |
8:58 |
|
8 |
—— |
4:32 |
3:32 |
2:32 |
1:32 |
12:32 |
11:32 |
9:32 |
|
9 |
—— |
4:51 |
3:51 |
2:51 |
1:51 |
12:51 |
11:51 |
9:51 |
|
10 |
—— |
5:48 |
4:48 |
3:48 |
2:48 |
1:48 |
12:48 |
10:48 |
|
11 |
—— |
6:10 |
5:10 |
4:10 |
3:10 |
2:10 |
1:10 |
11:10 |
|
12 |
—— |
7:00 |
6:00 |
5:00 |
4:00 |
3:00 |
2:00 |
12:00 |
The stages of the total lunar eclipse:
1) Moon enters penumbra
The shadow cone of the Earth has two parts: a dark, inner umbra, surrounding by a lighter penumbra. The penumbra is the pale outer portion of the Earth’s shadow. Although the eclipse begins officially at this moment, this is, in essence, an academic event. You won’t see anything unusual happening to the moon — at least not just yet. The Earth’s penumbral shadow is so faint that it remains invisible until the moon is deeply immersed in it. We must wait until the penumbra has reached roughly 70 percent across the moon’s disk. For about the next 50 minutes, the full moon will continue to appear to shine normally, although with each passing minute it is progressing ever deeper into the Earth’s outer shadow.
2) Penumbral shadow begins to appear
Now the moon has progressed far enough into the penumbra so that it should be evident on the moon’s disk. Start looking for a very subtle light shading to appear on the moon’s left portion. This will become increasingly more and more evident as the minutes pass, the shading appearing to spread and deepen. Just before the moon begins to enter the Earth’s dark umbral shadow, the penumbra should appear as an obvious smudge or tarnishing of the moon’s left portion.
3) Moon enters umbra
The moon now begins to cross into the Earth’s dark central shadow, called the umbra. A small dark scallop begins to appear on the moon’s lower left-hand (southeastern) limb. The partial phases of the eclipse begin; the pace quickens and the change is dramatic. The umbra is much darker than the penumbra and fairly sharp-edged. As the minutes pass, the dark shadow appears to creep slowly across the moon’s face. At first, the moon’s limb may seem to vanish completely inside of the umbra, but much later, as it moves in deeper, you’ll probably notice it glowing dimly orange, red or brown. Notice also that the edge of the Earth’s shadow projected on the moon is curved. Here is visible evidence that the Earth is a sphere, as deduced by Aristotle from lunar eclipses he observed in the 4th century B.C. It is almost as if a dimmer switch is slowly being turned down the surrounding landscape and deep shadows of a brilliant moonlit night begin to fade away.
4) 75 percent coverage
With three-quarters of the moon’s disk now eclipsed, that part of it that is immersed in shadow should begin to very faintly light up . . . similar to a piece of iron heated to the point where it just begins to glow. It now becomes obvious that the umbral shadow is not complete darkness. Using binoculars or a telescope, its outer portion is usually light enough to reveal lunar seas and craters, but the central part is much darker, and sometimes no surface features are recognizable. Colors in the umbra vary greatly from one eclipse to the next. Reds and grays usually predominate, but sometimes browns, blues and other tints are encountered.
5) Less than five minutes to totality
Several minutes before (and after) totality, the contrast between the remaining pale-yellow sliver and the ruddy-brown coloration spread over the rest of the moon’s disk and may produce a beautiful phenomenon known to some as the “Japanese Lantern Effect,” a term first coined by Long Island astrophotographer Peter A. Leavens in the 1950’s.
6) Total eclipse begins
When the last of the moon enters the umbra, the total eclipse begins. How the moon will appear during totality is not known. On very rare occasions, some eclipses are such a dark gray-black that the moon nearly vanishes from view. At other eclipses, it can glow a bright orange. The reason the moon can be seen at all when totally eclipsed is that sunlight is scattered and refracted around the edge of the Earth by our atmosphere. To an astronaut standing on the moon during totality, the sun would be hidden behind a dark Earth outlined by a brilliant red ring consisting of all the world’s sunrises and sunsets. The brightness of this ring around the Earth depends on global weather conditions and the amount of dust suspended in the air. A clear atmosphere on Earth means a bright lunar eclipse. If a major volcanic eruption has injected particles into the stratosphere during the previous couple of years, the eclipse is very dark. But, as of this writing, no such eruption has happened since our last total lunar eclipse in November 2021, so the betting is that this eclipse will be relatively bright.
7) Middle of totality
The moon is now shining anywhere from 10,000 to 100,000 times fainter than it was just a couple of hours ago. Since the moon is moving to the north of the center of the Earth’s umbra, the gradation of color and brightness across the moon’s disk should be such that its lower portion should appear darkest, with hues of deep copper or chocolate brown. Meanwhile, its upper portion — that part of the moon closest to the outer edge of the umbra — should appear the brightest, with hues of reds, oranges and even perhaps a soft bluish-white.
Observers away from bright city lights will notice a much greater number of stars than were visible earlier in the night.
The moon will lie near the border that separates the zodiac constellations of Leo and Virgo. The darkness of the sky is impressive. The surrounding landscape has taken on a somber hue. Before the eclipse, the full moon looked flat and one-dimensional. During totality, however, it will look smaller and three-dimensional — almost translucent, like some weirdly illuminated ball suspended in space.
At this moment, the moon is shining directly overhead from a point in the Pacific Ocean, 1,565 miles (2,520 km) northwest of the Galapagos Islands.
8) Total eclipse ends
The emergence of the moon from the shadow begins. The first small segment of the moon begins to reappear, followed again for the next several minutes by the Japanese Lantern Effect.
9) 75 percent coverage
Any vestiges of coloration within the umbra should be disappearing now. From here on, as the dark shadow methodically creeps off the moon’s disk and it should appear black and featureless.
10) Moon leaves umbra
The dark central shadow clears the moon’s right (western) limb.
11) Penumbral shadow fades away
As the last faint shading vanishes off the moon’s right portion, the visual show comes to an end.
12) Moon leaves penumbra
The eclipse “officially” ends as the moon is completely free of the penumbral shadow.
Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers’ Almanac and other publications.
Editor’s Note: If you snap a photo of the lunar eclipse and would like to share it with Space.com’s readers, send your photo(s), comments, and your name and location to [email protected].
