North America Favored for This Week’s Deep Partial Lunar Eclipse

Diana Hannikainen, Observing Editor, Sky & Telescope
+1 617-500-6793 x22100, [email protected]

Gary Seronik, Consulting Editor, Sky & Telescope
[email protected]

Susanna Kohler, Communications Manager and Press Officer, American Astronomical Society
+1 202-328-2010 x127, [email protected]

Note to Editors/Producers: This launch is accompanied by high-quality graphics; see the top of this launch for the photographs and hyperlinks to obtain.

Very late Thursday evening and early Friday morning, you will have an opportunity to observe the Moon darken and switch a reddish hue because it slips into Earth’s shadow. However, not like the entire lunar eclipse on May twenty sixth this year, the November 18–19 occasion is a partial eclipse. But it’s a really deep one: About 99% of the lunar disk’s space (97% of its diameter) will cross via the umbra — the darkish interior a part of Earth’s shadow — leaving a tiny, silvery sliver of the Moon’s southern edge peeking out.

Weather allowing, viewers throughout virtually all of North America will witness the whole thing of the occasion. November’s eclipse favors evening owls and early risers, as a result of the total Moon passes via the umbra after midnight on November nineteenth for the 4 important U.S. time zones, and mid-eclipse happens within the wee hours of the morning (at 4:03 a.m. EST and 1:03 a.m. PST). For Hawai’i and Alaska, the occasion begins to unfold earlier than midnight. 

Northeasternmost Asia will even see the whole occasion. In South America the eclipse occurs as daybreak is brightening, whereas for most of Australia the Moon will already be eclipsed because it rises. Much of western Europe ought to see the early penumbral phases earlier than the Moon dips under the horizon.

What to Look For

The partial eclipse is predicted to last more than normal, practically 3½ hours. In truth, not solely will it’s the longest partial lunar eclipse this century, it’s additionally the longest partial lunar eclipse between February 18, 1440, and February 8, 2669. It occurs 1.7 days earlier than the Moon reaches its apogee, or the farthest level from Earth, in its orbit. This signifies that the Moon’s orbital movement will likely be slower, thereby rising the period of the occasion.

“The Moon will be in Taurus and pleasingly placed some 6° — approximately the width of three fingers held together at arm’s length — lower left of the pretty Pleiades open star cluster at the time of maximum eclipse,” says Diana Hannikainen (pronounced HUHN-ih-KY-nen), observing editor at Sky & Telescope. “This should provide great opportunities for some fun photos.”

The phases of the eclipse happen concurrently for everybody who can see the Moon, however the precise clock occasions rely in your time zone. See the desk under and diagrams on the finish for occasions of key occasions for the lunar eclipse:

Moon enters penumbra 6:00 2:00 a.m. 1:00 a.m. 12:00 a.m. *11:00 p.m. *10:00 p.m. *9:00 p.m. *8:00 p.m.
Partial eclipse begins 7:18 3:18 a.m. 2:18 a.m. 1:18 a.m. 12:18 a.m. *11:18 p.m. *10:18 p.m. *9:18 p.m.
Maximum eclipse 9:03 5:03 a.m. 4:03 a.m. 3:03 a.m. 2:03 a.m. 1:03 a.m. 12:03 a.m. *11:03 p.m.
Partial eclipse ends 10:47 6:47 a.m. 5:47 a.m. 4:47 a.m. 3:47 a.m. 2:47 a.m. 1:47 a.m. 12:47 a.m.
Moon exits penumbra 12:06 7:06 a.m. 6:06 a.m. 5:06 a.m. 4:06 a.m. 3:06 a.m. 2:06 a.m.
*November 18th. Eclipse part occasions are proven for the contiguous U.S. time zones in addition to Alaska (Alaska Standard Time / AKST) and Hawai‘i (Hawai‘i-Aleutian Standard Time / HST).

Mechanics of a Lunar Eclipse

A lunar eclipse happens when the Sun, Earth, and a full Moon form a near-perfect lineup in space, in what is known as syzygy. The Moon gradually glides into Earth’s shadow, until most of the lunar disk turns from silvery grey to an eerie dim orange or red. Then events unfold in reverse order, until the Moon returns to full brilliance.

The events that happen during a total lunar eclipse are more complex and interesting than many people realize. The eclipse occurs in five stages, each with different things to watch.

(1) The Moon’s leading edge enters the pale outer fringe of Earth’s shadow: the penumbra. You probably won’t discover something till the Moon is about midway throughout the penumbra. Watch for a slight darkening on the Moon’s vanguard. The penumbral shading turns into stronger because the Moon strikes deeper in.

The penumbra is the area the place an astronaut standing on the Moon would see Earth protecting solely a part of the Sun’s disk.

(2) The Moon’s vanguard enters the umbra, the cone of Earth’s shadow inside which the Sun’s utterly hidden. You ought to discover a dramatic darkening on the higher left fringe of the lunar disk as seen from North America. With a telescope, you may watch the sting of the umbra slowly engulfing one lunar function after one other, as the whole sky begins to develop darker.

(3)  The trailing fringe of the Moon slips into the umbra for the start of most eclipse. The Moon will glow some shade of coppery red or burnt orange.

Why is that this? The Earth’s ambiance scatters and bends (refracts) daylight that skims its edges, diverting a few of it onto the eclipsed Moon. It’s the identical impact that occurs at sundown. If you had been on the Moon throughout a lunar eclipse, you’d see the Sun hidden by a darkish Earth rimmed with the reddish gentle of all of the sunrises and sunsets ringing the world at that second.

The red umbral glow will be fairly totally different from one eclipse to the subsequent. Two important components have an effect on its brightness and hue. The first is solely how deeply the Moon goes into the umbra because it passes via; the middle of the umbra is darker than its edges. The different issue is the state of Earth’s ambiance. If a serious volcanic eruption has just lately polluted the stratosphere with skinny international haze, a lunar eclipse will be darkish red, ashen brown, or often virtually black.

In addition, blue gentle is refracted via Earth’s clear, ozone-rich higher ambiance, above the thicker layers that produce the red sunrise-sunset colours. This ozone-blue gentle tints the Moon additionally, particularly close to the umbra’s edge, however you’ll want binoculars or a telescope to see this impact.

During this deep partial, a sliver of the southern fringe of the Moon’s disk will shine brightly even at mid-eclipse.

(4) As the Moon continues transferring alongside its orbit, occasions replay in reverse order. The sliver of sunshine will develop and develop upwards alongside the Moon’s vanguard.

(5) When all the Moon escapes the umbra, solely the final, penumbral shading is left. Some time later, nothing uncommon will stay seen.

“You only need your eyes to see the drama unfold, but if you have binoculars or a backyard telescope, they’ll give a much-enhanced view,” says Hannikainen.

Read extra on this eclipse within the November 2021 concern of Sky & Telescope and on S&T‘s web site: A Near-Miss Total Lunar Eclipse.

If it is cloudy the place you’re, you may comply with a reside stream of the eclipse on the Virtual Telescope website beginning at 7:00 UT on November nineteenth.

Sky & Telescope is making the illustrations under obtainable to editors and producers. Permission is granted for nonexclusive use in print and broadcast media, so long as applicable credit (as famous) are included. Web publication should embody a hyperlink to

Lunar Eclipse November 2021 UT
Events for the deep partial lunar eclipse on the morning of November 19, 2021. This model is labeled for Universal Time (UT). Other variations can be found for EST, CST, MST, PST, and unlabeled. Please consult with the desk above for corresponding occasions in numerous time zones. Click here or on the picture for a higher-resolution model.
Gregg Dinderman / Sky & Telescope; Source: USNO
Lunar Eclipse November 2021 coverage map
The map exhibits places worldwide from which the November 18–19 lunar eclipse is seen, climate allowing. Because an eclipsed Moon is at all times full, the Moon units (or rises) at virtually the identical time because the Sun rises (or units) on the other horizon. Click here or on the picture for a higher-resolution model.
Gregg Dinderman / Sky & Telescope; Source: USNO

Why does the Moon flip red? When the Moon falls in Earth’s shadow, not all daylight is blocked. A sliver of sunshine will journey via Earth’s ambiance, refracting — or bending — towards the Moon to then replicate off its floor. For the identical motive that the sky is blue, the blue wavelengths of daylight are scattered in Earth’s ambiance. Longer, redder wavelengths can cross via with out scattering — this is identical phenomenon that turns the Sun red when it’s close to the horizon. These photons are those that make it via to shine on the Moon. In a way, the Moon is seeing all of Earth’s sunrises and sunsets all of sudden. Rollover the icons to see mid-eclipse views from Earth and from the Moon. Click here for a high-resolution, annotated diagram.
Sky & Telescope
Before Image After Image
Why is not each full Moon an eclipse? The Moon’s orbit round Earth is tilted a small quantity, 5.14°, in comparison with the plane of Earth’s orbit across the Sun (exaggerated within the determine for readability). That signifies that most occasions, because the Moon orbits Earth, it evades Earth’s shadow — and when the Moon is reverse the Sun, we see it as a full Moon on Earth, its entire disk shining. However, roughly twice a year, the total part of the Moon coincides with a node, the place the Moon’s orbital plane crosses Earth’s orbital plane across the Sun. Depending on how shut the node is to the total Moon, we may even see a partial or complete lunar eclipse at these occasions. Use the slider to see how the setup adjustments.
Sky & Telescope
Earth's umbra at Moon
Earth’s umbra on the Moon’s distance spans about 9,000 kilometers or 1.3°, which is 2.6 occasions the diameter of the Moon. Given the Moon’s orbital tilt of 5.1° it is simple to see why eclipses do not occur each full Moon. (Earth’s umbra is proven right here as a darkish circle to show the idea, but it surely would not be seen on this way through the eclipse itself.)
Bob King

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