The full Flower Moon ducks inside Earth’s shadow in a total lunar eclipse this month. Prepare for all the highlights of the special event.

November 2021 Lunar eclipse
I made this sequence of the November 19, 2021, near-total lunar eclipse — emphasizing deepest eclipse — with a 94-mm refractor. This month's eclipse will be total.
Bob King

You can't do better for an astronomical event than a total lunar eclipse. It's visible to city and rural residents alike across half the planet, requires no special equipment, lasts for hours and is guaranteed to happen. How many other celestial shows offer this kind of ease and certainty? About the only thing that can get in the way are clouds. And for that, you can check current cloud maps to find the nearest clear skies. More about that in a moment.

May 15-16, 2022 Lunar Eclipse - coverage map
Use this map to determine how much of the eclipse will be visible where you live.
Gregg Dinderman / Sky & Telescope; Source: USNO

On Sunday night–Monday morning May 15–16, the Moon will undergo a total eclipse widely visible across the Americas, Europe, and Africa. From the East Coast partial eclipse begins about two hours after sunset, an hour after sunset for the Midwest, and near sunset for the mountain states.

Farther west along the West Coast, the moon will rise fully immersed in Earth's shadow. While that may make it sketchy to see at first, as the sky darkens, dramatic views of a highly reddened Moon near the horizon will make for stirring photographic possibilities. In the Eastern Hemisphere, European and African observers will witness the eclipse in the early morning hours and at dawn.

Lunar nodes
The moon's orbit briefly passes through the plane of Earth's orbit (ecliptic plane) twice each lunation — moving north of the plane at the ascending node and south of it at the descending node. If full Moon occurs within about 17° of a node crossing, an eclipse will occur somewhere on Earth, either partial, total, or penumbral. If the Moon is in new phase, a solar eclipse results. Complex interactions between the Sun, Earth, and Moon cause the nodes to precess around the ecliptic with a period of 18.6 years.
Tom Ruen

A nod to nodes

Total eclipses would occur at every full Moon if the Moon's orbit were coplanar with the Earth's, but it's inclined by 5.1°. The two orbits intersect at two places called nodes. If the Moon happens to be full at the same time that it crosses at or near a node, it will pass directly into Earth's shadow, and we'll see an eclipse. That typically happens twice a year with a maximum of three and minimum of zero. Happily, 2022 is one of those "typical" years, with a second total eclipse falling on November 7–8 and also visible in the Americas.

How lunar eclipses happen
When a full Moon crosses a node, it travels through Earth's two-part shadow and is eclipsed. In the penumbra or outer shadow, the globe of the Earth partially blocks the solar disk, resulting in a faint shading visible across half the Moon about half an hour before the start of partial eclipse. The first dark "bite" occurs as the Moon enters the umbra, where the Earth completely blocks the Sun's glaring disk — save for reddened sunlight that filters through the atmosphere and into the umbra to color the Moon red.
Starry Night with additions by Bob King

If you can only afford a half-hour, watch the transition from partial to total (or total to partial if you live in the far west) eclipse. But if you're able, try to observe as much of the event as possible, so you can experience the majesty of the event at nature's pace. The primary eclipse lasts nearly 3½ hours, with an additional ~20 minutes of penumbral shading visible on either side.

Let's check out the highlights.

May 15-16, 2022 Lunar Eclipse Phases - UT
This diagram shows the key phases of the May 15–16 eclipse as the Moon passes through Earth's shadow. Times are Universal Time (UT). Click the following links for custom time zone maps for EDT, CDT, MDT, PDT
Gregg Dinderman / Sky & Telescope; Source: USNO
Eclipse EventUTADTEDTCDTMDTPDTAKDT
Penumbra first visible?~2:00~11:00 p.m.~10:00 p.m.~9:00 p.m.
Partial eclipse begins2:2811:28 p.m.10:28 p.m.9:28 p.m.*8:28 p.m.
Total eclipse begins3:2912:29 a.m.11:29 p.m.10:29 p.m.9:29 p.m.*8:29 p.m.
Mid-eclipse4:121:12 a.m.12:12 a.m.11:12 p.m.10:12 p.m.9:12 p.m.
Total eclipse ends4:541:54 a.m.12:54 a.m.11:54 p.m.10:54 p.m.9:54 p.m.
Partial eclipse end5:562:56 a.m.1:56 a.m.12:56 a.m.11:56 p.m.10:56 p.m.*9:56 p.m.
Penumbra last visible?~6:30~3:30 a.m.~2:30 a.m.~1:30 a.m.~12:30 a.m.~11:30 p.m.~10:30 p.m.
Total eclipse of the Moon on May 15–16, 2022. Asterisks indicate that the phase occurs around moonrise.
Source: USNO

Phase transitions

Penumbral permutations
Understanding the penumbral shadow is easy. Just look at the shadow cast by a tree. The inner portion represents the umbra, where the trunk blocks all direct sunlight. Some sunlight leaks into the shadow's edge, creating a fuzzy, pale penumbral border. At right, the penumbral shadow shades the Moon during the February 10, 2017 eclipse.
Bob King

Penumbral eclipse — Look for a subtle shading along the eastern third-to-half (bottom left for U.S. observers) of the Moon. When will it first become visible — 30 minutes before partial eclipse? 15 minutes? Can you detect color and depth of shading or is it a uniform gray?

Partial eclipse — At what point does the shadowed portion of the Moon appear red in binoculars? With the naked eye? Because it absorbs red light, the atmospheric ozone layer often imparts a turquoise hue to the edge of encroaching umbral shadow. You'll need a small telescope to see the coloration, but it's surprisingly obvious once you look for it.

Telescope users can also time when the shadow's edge passes over individual craters to help determine how changes in the Earth's atmosphere cause the expected diameter of the umbra to vary. For predictions and a chance to share your observations, visit Roger Sinnott's Useful Projects for a Lunar Eclipse.

Moon totality
During totality the Moon appears in Libra approximately halfway between Alpha (α) Librae, better known as Zubenelgenubi, and Antares in Scorpius.
Sky & Telescope

Totality — Since the Moon crosses the southern half of the shadow's core and not dead-center, you should see a noticeable difference in brightness and color between its southern hemisphere, located near the umbra's periphery, and the northern hemisphere, which almost touches the center. These contrasts will work together to enhance the Moon's three-dimensional appearance as a smoldering orb floating among the stars.

A dark eclipse?

The clarity of the atmosphere also affects the Moon's brightness and color during totality. Eclipsed moons can range from yellow-orange to rusty red or even brownish-gray. Dark eclipses are often tied to dust and other particulates released from volcanic activity. The powerful Tonga submarine volcano eruption that began last December and climaxed in January released a massive amount of aerosols into the upper atmosphere which still linger four months later.

Tonga volcano
The Japanese weather satellite Himawari-8 took this sequence of photos of the Tonga volcano eruption on January 15, 2022.
Japan Meteorological Agency / CC BY-SA 4.0

Helio Vital, with the Brazil lunar-eclipse watchers, predicts that the "additional absorption layer will darken the Moon at totality by 1.5 magnitude, rendering it a very dark eclipse with a total magnitude of +0.9 (+/– 0.9 mag.)." The same eclipse viewed through a "clean atmosphere" would otherwise shine at magnitude –0.6 (+/– 0.6 mag.) at mid-eclipse. Vital writes:

Danjon scale
Astronomers use this five-step Danjon scale to judge the darkness of the Moon during a total lunar eclipse.
Sky & Telescope illustration

"Then the totally eclipsed Moon, some 0.3 million times dimmer than the usual full Moon, will be rivalling Antares in brightness, and most eclipse gazers will be amazed to see it so faint and colorless, estimating it at L=1  on the Danjon scale." As the volcanic material spreads more evenly and completely around the globe, Vital forecasts even darker eclipses next year.

How deeply will the Moon be affected by the eruption? Use the Danjon scale chart to make your own estimate and drop us a line in the comments section. And while you're at it, also keep an eye out for any potential impacting meteoroids during totality. A strike will appear as brief, pinpoint flash against the darkened Moon.

Eclipse occultation
From Chicago the fully eclipsed Moon will occult the double star S672 about 10:45 p.m. CDT on May 22nd. Since the components, magnitudes 6.3 and 8.9, are separated by just 11.2″ and aligned nearly east-west, observers will witness two occultations about 20 seconds apart.
Stellarium

Double take

For observers across much of the U.S., Canada, and parts of Mexico and South America the Moon occults the 6th-magnitude double star S672 around 3:45-4 UT, May 16. From the southwestern U.S. eclipse-watchers instead will see an occultation of 5.5-magnitude HD 138413. From Tucson, Arizona, the totally eclipsed Moon covers the star from 8:30 p.m. to 9:09 p.m. MST.

After factoring in your time zone, occultation times still vary due to lunar parallax. To determine exact times for your location, simulate the event using a star app or Stellarium.

Earth from Moon
From the Moon (the Apollo 11 landing site location here, but with a generic backdrop), an astronaut would witness the Earth totally eclipsing the Sun. The glowing ring around the planet is reddened sunlight filtered through the atmosphere and into the umbra.
Sky & Telescope

While the transition from daylight to semidarkness happens rapidly during a total solar eclipse, the lunar version is more casual, though not without the power to touch our emotions. As totality approaches, the sky darkens by degrees until all the stars return. Drained of direct sunlight the Moon loses its thrall over the heavens. I don't know how, but the loss of moonlight makes it feel quieter outside. Hushed. Observers under rural skies get to witness the dramatic return of the Milky Way.

Besides totality itself, my favorite phases are the twin 5-minute intervals immediately before and after, when a narrow sliver of uneclipsed Moon stands in vivid contrast to the dark, umbra-soaked globe.

Resources

As the Moon exits the Earth's shadow, you can continue to observe each phase but in reverse. Many of us will be photographing the eclipse. I recommend Fred Espenak's guide How to Photograph a Lunar Eclipse for tips. At the top I mentioned clouds. Should they threaten, here are some resources to help you find the nearest clear sky:

Weather Network interactive satellite cloud viewer
 U.S. 7-Day Cloud Cover Forecast
GOES-East and GOES-West live satellite images
Astrospheric smoke forecasts (from smoke from New Mexico wildfires, which could affect both the Moon's color and visibility)

If there's no escape, Italian astronomer Gianluca Masi will live-stream the eclipse on his Virtual Telescope site on May 16th starting at 2:15 UT (10:15 p.m. EDT on May 15th). You'll find additional streaming options at Griffith Observatory and timeanddate. Wishing you a wonderful night out. And if you have kids, let 'em stay up late!


Read more on the May 15–16 lunar eclipse in the May issue of Sky & Telescope.


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Comments


Image of Joe Stieber

Joe Stieber

May 10, 2022 at 12:51 pm

Bob -- another great resource for observers!

And thanks for the head's up on the occultation of S 672. I would add that due to the moon's proximity, and therefore not necessarily inconsequential parallax, one can't simply add or subtract even hours to the listed time for Chicago ("about 10:45 pm CDT") to adjust for different time zones.

Here in the Philadelphia-South Jersey area (nominally 40°N-75°W), both SkyTools and SkySafari show the secondary star of the pair winking out first at about 12:03 am EDT on May 16. That's 18 minutes difference using UT for each location -- Chicago 03:45 UT, Philadelphia 04:03 UT.

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Bob King

May 10, 2022 at 1:15 pm

Thanks, Joe. Yes, I only gave the Chicago time as an example but have since added the UT time and a link for observers to determine their own particulars. Times vary across the board as you pointed out due to parallax. Thank you, much appreciated!

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Anthony Barreiro

May 10, 2022 at 6:24 pm

Thanks very much Bob. I've been telling friends, family, and coworkers, especially parents with younger children, about this eclipse. Perfect timing for the little ones!

One small correction: in the eclipse event timetable, the "total eclipse ends" times for CDT, MDT, and PDT are stated as a.m. They should be p.m.

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Anthony Barreiro

May 10, 2022 at 6:30 pm

P.S. There's an article about the eclipse in the San Francisco Chronicle. They're calling this eclipse a “super flower blood moon.” Yuck.

Oh well. As P.T. Barnum (may have) said, "there's no such thing as bad publicity."

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Bob King

May 11, 2022 at 12:37 am

Anthony,
That reminds me of reading the menu in some restaurants. Long ago, I got into the habit of stripping away all the adjectives to see what I was actually ordering.

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Bob King

May 11, 2022 at 12:34 am

Thank you, Anthony. Good catch. Now corrected.

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Karlacasford

May 11, 2022 at 11:01 am

Hi unsure if this has been asked but will the West Coast of Australia see the eclipse or East Coast or New Zealand or East Coast of Canada? My family is spread out and something like this is awesome to see with our children and elderly parents,means we are connected to us.
Thankyou.

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Bob King

May 11, 2022 at 11:10 am

Hi Karla,
To answer your question, there's good news and bad news. Bad news first — the eclipse won't be visible in Australia and New Zealand. Good news — all of it will be visible from the East Coast of Canada! Check the table in the post for times to watch.

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Karlacasford

May 11, 2022 at 11:50 am

Ohh what a stinker,well im sure my brother and his children will have prime positions up on a mountain somewhere.
Thankyou for answering that,now to break it to my mum in nz.

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Rich

May 13, 2022 at 11:50 pm

Hi Karla,
As a consolation for your New Zealand relations, their is another Total Lunar Eclipse on November 8, 2022 and New Zealand will see the entire eclipse.

For the east coast of Australia, the eclipse will start earlier (local time) in the evening. They will see the start of the partial phase, but the Moon will be low in the East. They will see all of totality.

For the west coast of Australia, the eclipse will start even earlier (local time) and they will miss the start of the partial phase and the start of totality. They will see the end of totality, but the Moon will be low in the East.

BTW, if you could go from Perth through the center of the Earth, you would wind up somewhat to the southeast of Bermuda.

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StanR

May 14, 2022 at 12:22 am

Thanks. I have to say, though, I found the map confusing since "May 16" appears on it twice, yet the eclipse starts the evening of May 15 for most. I finally realized that "Evening of May 16" is technically correct, since it appears to the left of the International Date Line, but I think it would be clearer if May 15 or 15-16 also appeared on it somewhere applicable. (Perhaps "Night of May 15-16" somewhere near the Western Hemisphere continents.)

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GaryN

May 15, 2022 at 1:41 pm

Bob, are you allowed to include these images? Astrospheric has been posting animations of the forecast(s) during the eclipse this evening that have been pretty interesting. Especially the smoke from the fires in New Mexico. https://twitter.com/astrospheric_wx

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Bob King

May 15, 2022 at 2:37 pm

Hi Gary,

Thanks for the link! Permissions might be tough with those, but I can sure add it to the links as a resource.

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John Jones

May 16, 2022 at 12:24 am

In Woodstock, GA, I judge the portion of the moon closest to the center of the umbra to be 0 on the Danjon scale, no features of the moon surface are visible to me. The edge nearer to the penumbra is 2.

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Bob King

May 16, 2022 at 2:15 am

Hi John,

I concur. It was a dark eclipse! I could faintly see the northern limb at mid-eclipse from my location with the naked eye. I gave it an overall "1" on the Danjon scale. Thanks so much for sharing your observation. People really appreciate when they can compare their observations with others.

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Jwandass3

May 16, 2022 at 12:37 am

We observed the total lunar eclipse while on vacation in Cozumel, Mexico. It was 78° with partly cloudy skies. At maximal eclipse, we estimated a Danjon scale brightness between one and two.

Joe & Lisa Wandass
James & Alison Weglarski

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Bob King

May 16, 2022 at 2:16 am

Hi Jwandass3,

Much appreciated! Thank you for sending in your estimate. Preliminary observations indicate a dark eclipse. Enjoy those beautiful vacation skies!

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