Sky ArchiveTonight

Subtle lunar eclipse on February 10-11

Tonight – February 10, 2017 – you might think the full moon looks slightly darker than a typical full moon, if you catch it as it’s passing through the Earth’s faint penumbral shadow. There’s a penumbral lunar eclipse tonight, the most subtle kind of eclipse. Some people will easily notice Earth’s light penumbral shadow, inching across the moon’s face. Others will look at tonight’s full moon and swear they notice nothing unusual.

The star near the moon on eclipse night is Regulus, sometimes called the Heart of the Lion, brightest star in the constellation Leo.

As always, to see the eclipse, you have to be in the right place on Earth. The map below shows who will witness this one.

The world’s Western Hemisphere (North and South America, Greenland) sees the penumbral eclipse of the moon on the evening of Friday, February 10. The world’s Eastern Hemisphere (Europe, Africa, Asia) sees the eclipse on Saturday, February 11. Read more.

As far as the Americas are concerned, the penumbral eclipse will be most easily viewed from the eastern portions of North and South America, after sunset February 10. Along the American Pacific Coast, a shallow penumbral eclipse will have to contend with the glare of evening twilight. For the most of North America, the moon will be in eclipse at moonrise (sunset) on February 10 and will hard to see in evening twilight.

The ideal spot to watch this penumbral eclipse is from Europe, Africa, Greenland and Iceland. From there the whole eclipse can be seen, from start to finish, and it occurs at late night in a dark sky.

In Asia, the eclipse will be obscured by morning twilight on February 11 and will be in eclipse at moonset (sunrise) February 11.

Lunar eclipse computer via US Naval Observatory (select date of eclipse and location from pop-up list)

For all of us, the moon travels from west to east across the Earth’s penumbral shadow, to the south of the umbra (dark shadow). The north side of the moon will be noticeably darker because it’s closer to the umbra. The animation below, from Larry Koehn of the beautiful website shadowandsubstance.com, illustrates:

Penumbral Eclipse of the Moon February 10 – 11, 2017 from LarryKoehn on Vimeo.

The Earth’s shadow is composed of two parts: the inner dark cone-shaped umbra and the faint penumbra surrounding the umbra, as shown on the image below. So be forewarned. A penumbral eclipse is nowhere as dramatic as a total or even partial umbral lunar eclipse.

Although the whole eclipse, from start to finish, lasts for some four and one-third hours, the beginning and ending stages are not visible to the eye. Given a dark sky, free of twilight glare, the eclipse might be visible to the eye for an hour or two, centered on the greatest eclipse (February 11 at 00:44 UTC). At North American time zones, that means the greatest eclipse will happen on February 10, at 8:44 p.m AST, 7:44 p.m. EST, 6:44 p.m. CST, 5:44 p.m. MST, 4:44 p.m. PST and 3:44 p.m. AKST.

A lunar eclipse can only happen at full moon, but more often than not the full moon swings above or below the Earth's shadow. On February 11, 2017 the full moon swings south of the dark umbra but passes through the faint penumbra.
A lunar eclipse can only happen at full moon, but more often than not the full moon swings above or below the Earth’s dark umbral shadow. The February 10-11, 2017 full moon swings south of the umbra but passes through the fainter penumbral shadow.

We list the times of the penumbral eclipse first in Universal Time (UTC), and then in local time at North American time zones:

Penumbral eclipse begins: 22:34 UTC (on February 10)

Greatest eclipse (nearest umbra): 00:44 UTC (on February 11)

Penumbral eclipse ends: 02:53 UTC (on February 11)

How do I translate UTC to my time?

For North American time zones (on February 10):

Atlantic Standard Time
Penumbral eclipse begins: 6:34 p.m. (on February 10)
Greatest eclipse (nearest umbra): 8:44 p.m. (on February 10)
Penumbral eclipse ends: 10:53 p.m. (on February 10)

Eastern Standard Time
Penumbral eclipse begins: 5:34 p.m. (on February 10)
Greatest eclipse (nearest umbra): 7:44 p.m. (on February 10)
Penumbral eclipse ends: 9:53 p.m. (on February 10)

Central Standard Time
Penumbral eclipse begins: 4:34 p.m. (on February 10)
Greatest eclipse (nearest umbra): 6:44 p.m. (on February 10)
Penumbral eclipse ends: 8:53 p.m. (on February 10)

Mountain Standard Time
Penumbral eclipse begins: 3:34 p.m. (on February 10)
Greatest eclipse (nearest umbra): 5:44 p.m. (on February 10)
Penumbral eclipse ends: 7:53 p.m. (on February 10)

Pacific Standard Time
Penumbral eclipse begins: 2:34 p.m. (on February 10)
Greatest eclipse (nearest umbra): 4:44 p.m. (on February 10)
Penumbral eclipse ends: 6:53 p.m. (on February 10)

Alaskan Standard Time
Penumbral eclipse begins: 1:34 p.m. (on February 10)
Greatest eclipse (nearest umbra): 3:44 p.m. (on February 10)
Penumbral eclipse ends: 5:53 p.m. (on February 10)

Lunar eclipse computer via US Naval Observatory (select date of eclipse and location from pop-up list)

Akash Anandh in Singapore caught a September, 2016 penumbral lunar eclipse as it progressed.

Although the residents of Australia and New Zealand will miss out on this penumbral lunar eclipse completely, a different sort of eclipse will occur in their sky. The moon will occult (cover over) Regulus, the brightest star in the constellation Leo, on the night of February 11. For instance, from Perth, Western Australia, the occultation takes place on February 11 from 8:39 p.m. to 9:51 p.m. local time. However, the full moon’s glare may make it difficult to observe this lunar occultation. Click here for more information.

The February 10-11 penumbral lunar eclipse is the first eclipse of 2017 and the first of two eclipses this month. The second eclipse is a ring of fire eclipse on February 26.

This photo – from James Jacolbia in Quezon City, Philippines, shows a moon with no eclipse (left) and the moon undergoing the March 23, 2016, penumbral lunar eclipse (right).

Bottom line: Ideal spots to watch the February 10-11, 2017 penumbral lunar eclipse include Europe, Africa, Greenland and Iceland. From there the whole eclipse can be seen, from start to finish, and it occurs at late night in a dark sky. Eastern America has a better view of the eclipse than western America.

Posted 
February 10, 2017
 in 
Sky Archive

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