Eclipse! Full Hunter’s Moon Takes A Dip In Earth’s Shadow Friday Night

The moon is eclipsed by Earth’s penumbral shadow Friday night. The eclipse begins at 4:53 p.m. CDT, reaches maximum at 6:50 p.m. and ends at 8:48 p.m. Add one hour for Eastern time; subtract an hour for Mountain and 2 hours for Pacific. Credit: Wikipedia with my own additions

Seems like every cool astronomical event happens on a Friday lately. Tomorrow night, the Full Hunter’s Moon takes a dip in Earth’s shadow across much of the Americas, Europe, Africa and West Asia. Between 4:53 and 8:48 p.m. CDT 3/4 of the lunar disk will be eclipsed by the planet’s outer shadow or penumbra. Penumbral eclipses are cousins of the more familiar and dramatic total lunar eclipses.

When sun, Earth and moon align we get treated to a lunar eclipse. Penumbral eclipses occur when the moon passes through the Earth’s outer shadow into which a partial amount of sunlight spills. Credit: Fred Espenak

For any lunar eclipse to happen, the moon must be full and the sun, Earth and moon precisely lined up in that order. In this arrangement, the full moon drifts directly into Earth’s shadow producing a lunar eclipse.

Wish it were that easy every full moon. Because of its tilted orbit, the moon misses Earth’s shadow during most full moons and instead we see … a full moon. But several times a year, the moon happens to be full at the very hour it’s exactly aligned with sun and Earth. Voila! Its shiny disk is quenched by shadow.

The umbra is very dark because the Earth completely covers up the sun from the moon’s perspective (bottom). The penumbra is a mix of shadown and sunlight because a portion of the sun is still visible from the lunar perspective (top). Credit: Wikipedia

Earth’s shadow has two parts – umbra and penumbra – making three types of lunar eclipses possible:

* Total – where the moon passes completely into the Earth’s umbra or inner shadow. This variety is the most highly anticipated. Deeply reddened sunlight bent by Earth’s atmosphere filters into the shadow, transforming the moon into a dramatic coppery disk. Amateur astronomers have been known drive up to several hundred miles to see one. Don’t ask me how I know this – I just do.

* Partial –  a near but not exact lineup where only a portion of the moon drifts through the inner shadow, giving it the appearance of a cookie with a bite out of it.

* Penumbral – Completely misses the inner shadow but glides through the penumbra or outer shadow. Because a portion of the sun shines into the penumbra, it’s not nearly as dark as the umbra. That’s why penumbral eclipses are subtle compared to partials and totals.

Normal full moon (left) and how the moon will look Friday during maximum eclipse. Credit: Fred Espenak

Friday’s eclipse occurs during early evening hours for North America (midnight-1 a.m. in Europe); no setting of alarm clocks is required.

Some penumbral eclipses, those where the moon only dips a toe in shadow, are barely noticeable. Not this one. At maximum eclipse (6:50 p.m. CDT), 76 percent of the moon will take the penumbral plunge. At the very least, you’ll notice that the right side of the moon (as seen from North America) looks gray and out of round.

For many of us, maximum eclipse will occur when the moon is low in the eastern sky shortly after sundown. That means you’ll need to plan ahead to find a place with a clear view in that direction. Bring a camera. The scenic potential of the moon rising in Earth’s purple-gray shadow while in penumbral eclipse is worth burning up a few dozen frames.

Visibility map for Friday’s eclipse (Sat. a.m. Oct. 19 in Europe and Asia). Across most of the Americas the moon rises in the east around sunset with the eclipse already underway. The eastern half of the country will see maximum eclipse. From the Mountain time zone westward, less of the moon will be in shadow. No eclipse is visible from Alaska. Credit: NASA

In Europe, the moon will fly high in the south at eclipse time and be ideally placed for viewing, though lacking in sunset scenery potential like that in the U.S.

We’ve been living on meager eclipse rations for some time now in the Americas. That changes next year when two total lunars will darken the sky – the first on April 15 and a second on October 8. Get ready for more tales from the shadow world!

Just a quick note. I’ll be working on other projects in the next few days, so if you come by and don’t see a daily update you’ll know why.

9 Responses

  1. Edward M. Boll

    As far as the planet comet line up for November 9, the prediction a few weeks ago was Comet Encke at magnitude 6 , ISON beteen 6 and 7, and Lovejoy 9. In reality the prediction is probably right for the other 2. But, I believe that Lovejoy could even be brighter than Encke by then.

  2. Edward M. Boll

    Jupiter as one of the first bright objects I paid attention to in the late Summer of 1985. I as new to Astronomy then but excited about Comet Halley.

  3. I took some photos during and about an hour after maximum eclipse and posted them on my blog I used my canon xs on a sturdy tripod with a 250mm zoom lens and cropped the photo to just include the moon.

    I went out at the time of max eclipse and noticed the shading. I heard some people weren’t able to tell if the (faint) eclipse was in progress. I wonder if it was harder to see the subtle shading gradually increase on the very bright moon. I might have been able to see the shading because I only looked at maximum eclipse. I took photos with lots of different exposures, which was good. When I took the later photo, the moon was brighter because it was higher in the sky. A photo with a shorter exposure matched better the brightness of the moon during the eclipse. See my blog for the three photos: during, after at the same exposure and after at a shorter exposure.

    1. astrobob

      Thanks Bob. Yes, max eclipse time was the best time to see the shadow shading. Wish I could have seen and photographed it myself but I was out of town.

  4. Sean

    this event was interesting. when i viewed the moon about 15 minutes b4 peak eclipse, i was not sure i could see shading. even with binos. i mean, i could see there was some dark shading along the southern moon but honestly couldn’t remember exactly what it usually looks like, in comparison. later, observing the moon past 10PM, naked-eye, it was obvious that the southern part is absolutely the brightest part during full moons when not eclipsed! so obviously a noticeable difference. but it made me realize that i hadn’t paid enough attention previously to be sure there was a difference. which was a minor revelation.

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