Make the Most of January's Total Lunar Eclipse

By: Bob King January 24, 2018 16

An unusual dawn total lunar eclipse presents special challenges and great photo opportunities. Here's what you need to know to make the most of it.

Burnt orange beauty — It's coming soon! The Moon will be totally eclipsed for the Americas, Australia, and East Asia on January 31st.
*Bob King*

It's fun to watch the Moon fatten up this month knowing that when it's full, we'll have a total lunar eclipse. Be sure to mark the date — Wednesday morning, January 31st.

This will be the year's only eclipse of any kind for U.S. observers, so it's worth the effort to get up early to see it. For observers in the Western Hemisphere, the event happens in the pre-dawn or dawn sky close to the western horizon only an hour or two before sunrise; the farther west you live, the higher the Moon will be in the sky and the more of the eclipse you'll see.

Should clouds threaten, plan a road trip. After last year's total solar eclipse, it doesn't feel weird anymore to drive a hundred miles or more to see a big-time astronomical event. Consult ClearDarkSky and NOAA Satellite Images to make a quick getaway to clear skies. If you're still unable to see it, NASA and Griffith Observatory will offer live feeds.

There's lots of online chatter about this being a Blue Blood Supermoon Eclipse or Super Blue Blood Moon Eclipse or some variation thereof. While all these adjectives are accurate, we don't need them. Every total lunar eclipse is unique and wonderful.

The January 31st full Moon is the second of the month, making it a Blue Moon, at least in the modern sense. The original meaning of the term was the third of four full Moons in a season. By this definition, the next Blue Moon won't occur until May 18, 2019. But take your pick.

West is best — How much of the eclipse you'll see depends on how far west you live.
*Sky & Telescope*

The full Moon will also be closer and larger than usual since it reaches perigee (358,994 km) the previous day. This qualifies it for supermoon status. Finally, only the "bloody end" of the Sun's light will remain to illuminate the Moon within Earth's shadow, with the rest scattered away by the atmosphere. Lunar color during an eclipse depends on the clarity of the atmosphere. The less dust, the brighter the Moon's shade. I've seen it as orange as a glowing coal, but during times of strong volcanic activity, the ash-and-volatile-laden air can turn the Moon's hue from blood to mud.

Umbra color schematic — If Earth had no atmosphere, the Moon would look completely black during a total lunar eclipse. However, a little of the Sun's light refracts through the atmosphere and into Earth's umbra, coloring the lunar disk during totality. (Not to scale.)
*Sky & Telescope*

Due to the Moon's low altitude, particularly for those who live in the eastern half of the country, I prepared a series of four maps, one for each time zone, showing its location, general appearance, and altitude at key phases of the eclipse. Altitudes are measured in degrees. A fist held vertically at arm's length spans 10° from top to bottom; index, middle, and ring fingers held together cover 5°, and your little finger masks 1° of sky, or two Moon diameters.

Only a bite — This map is drawn for the Eastern time zone centered at Roanoke, Virginia. Only partial eclipse phases will be visible from the eastern states, and the Moon will be very low in the western sky — only 6° at eclipse start. East of Roanoke, the Moon will be a little lower yet, while at the western fringe of the time zone, it will be a little higher.
*Bob King*

You'll find links to additional diagrams showing the Moon's progress through Earth's shadow with key times and aspects of the eclipse for each time zone at the end of this blog. While the growing light of dawn will compete with the eclipse viewing from the eastern U.S., don't be put off. Your narrow viewing window makes this a very special event for both photography and spiritual-spatial relations.

Two courses better than none — Des Moines, Iowa, was chosen to represent the Central time zone. Here, the early stages of totality will be visible before moonset. Use binoculars around the time of totality as the Moon will appear faint. If you start watching the eclipse about a half-hour before the partial phases begin, you can spy the dusky, gray shadow of the penumbra across the top third of the lunar disk.
*Bob King*

The Moon's low elevation means we can frame it with familiar landmarks, and the fact that the eclipse occurs at dawn means there will be a good balance of light between the landscape and the Moon. Try to include buildings, an iconic vista, or even morning traffic in the lower half of the frame with the partially or fully eclipsed Moon near the top. The longer the telephoto lens you use, the more dramatic the Moon will appear in comparison to the landscape. Experiment with exposure to get it just right and don't forget that tripod! Refer to this excellent exposure and composition guide by Fred Espenak for tips and details. For more on the eclipse, see Sky & Telescope's earlier story.

In the red! — Citizens of the mountain states will be able to watch the Moon up to just past mid-eclipse. Shortly before and during early totality, watch for the Beehive Cluster (M44) to pop into view 3.5° to the upper right (NW) of the Moon.
*Bob King*

We've all read that the full Moon lies directly opposite the Sun from our point of view, but that's only about 95% true. Most full Moons are off a couple of degrees from a perfect lineup. The only time they're (nearly) exactly so is during a total lunar eclipse. From the Central and Mountain time zones, the full Moon will set in total eclipse; at the same time, the Sun rises at your back. For once, we can look ahead to the Moon, then back around at the Sun and find ourselves in the middle right here on Earth. At that moment, it won't be just a diagram anymore.

Whole enchilada — California, here we come! Skywatchers will see the entire eclipse from the West Coast, Alaska, and Hawaii. Note: the fully-eclipsed Moon's aspect (position of features on the disk) is for illustration only.
*Bob King*

Sky & Telescope diagrams showing the Moon's progress through the Earth's outer shadow (penumbra) and inner shadow (umbra) are available here:

Moon meets Duluth — It'll be easy to frame the low, eclipsed Moon and a scene at dawn on Wednesday, January 31st. This photo was taken in 1999 from the city of Duluth, Minnesota, with a 300-mm telephoto lens. The next total lunar eclipse, on January 20–21, 2019, will be visible across all of North and South America during convenient evening viewing hours.
*Bob King*

Comments

Anthony Barreiro

January 24, 2018 at 4:51 pm

Thanks Bob for this excellent primer on spiritual-spatial relations. I hope you (and I) have clear skies for the eclipse!

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Bob KingPost Author

January 24, 2018 at 11:26 pm

Thanks, Anthony. Clear skies your way!

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Magellan

January 25, 2018 at 9:37 pm

Thanks for the informative article. i did want to point out that we in the 49th and 50th states in the union are feeling a bit left out. Hopefully, we will have clear skies. Even more hopeful is the possibility of Northern Lights and an eclipse for us in Alaska.

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Bob KingPost Author

January 26, 2018 at 12:14 am

Hi Magellan,
The 49th and 50th were in my heart (plus my brother lives north of Anchorage) but alas, I couldn't do maps for them all. I hope you have clear skies, and they'll get dark enough to see the aurora if it drops by.

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Graham-Wolf

January 25, 2018 at 10:20 pm

Best of luck to you BOTH.

I'm blessed with 76 minutes of pure totality (if the weather gods oblige).
Murphy.... don't even THINK of messing me up!!!

Roger's article on this site is a god primer for those wanting to crater time the eclipse.
I've had 40+ years of THAT..... thanks again,Roger for the Crater predictions.
Dr Eclipse (aka "you-know-who" from NASA-Goddard has some excellent websites for this).
Yes... Fred Espenak!

Worth a good look.

Best wishes from
Graham W. Wolf at 46 South, Dunedin, NZ.
'
P.S. Awesome pics of Duluth.... you should be writing for National Geographic, Bob!

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Bob KingPost Author

January 26, 2018 at 12:15 am

Thanks, Graham! 76 minutes of totality sounds sweet. My forecast which looked hopeful a day ago is now filled with clouds 🙁

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tom-mangelsdorf

January 26, 2018 at 4:44 pm

Not every total lunar eclipse is a blood moon!!!!! I repeat: Not every total lunar eclipse is a blood moon!!!!! A lunar eclipse is not referred to as a blood moon just because it is red. A blood moon is a part of a tetrad. A tetrad is a series of 4 lunar eclipses in a row all separated by 6 full moons, with no partial lunar eclipses in the span. The last tetrad we had was in April 2014 thru September 2015. The newspapers and television and social media references to a blood moon for those 4 eclipses was correct, but they never explained the origin of the term. Since then everyone uses the term blood moon, thinking it has only to do with the red color of the deeply eclipsed moon.

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Bob KingPost Author

January 27, 2018 at 12:31 am

Hi Tom,

A blood moon isn't a scientific term, and as far as I can determine is completely cooked-up as it relates to tetrads. It appears to be based on modern-day superstition. The original reference to the 'blood moon' goes back to the Bible and matches the description of a total eclipse, but without any mention of tetrads and the like. What is your source for the tetrad interpretation of blood moons?

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Glenn

January 26, 2018 at 6:17 pm

Trying to see a totally eclipsed moon setting as the sun rises is well nigh impossible. The sky will be too bright due to the oncoming dawn. The dark red moon will simply not be bright enough to see with the naked eye. Don't leave it to the last minutes to try and see the setting moon but give it at least 45 minutes before moonset. Then keep checking every 5 minor so until it is no longer visible to the eye, then with binoculars... G

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Bob KingPost Author

January 27, 2018 at 12:20 am

Thank you Glenn for the caution! Within a few degrees of the horizon, it will be tough to see if sunrise is just minutes away. In the Midwest, it arrives at total eclipse at around 5-6° altitude, possibly just high enough to glimpse before it disappears.

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Nils M

January 28, 2018 at 6:32 pm

Hi Bob,
Thanks for a great article. I am looking forward to the blood moon eclipse. I have a question maybe you know the answer to. When does the star Sirius rise in northern Sweden? For example Östersund located at 63º N? Your previous article "a real scorcher" only went up to 50º N. Since it increased one day later per degree, am I correct to assume it would rise 13 days later, September 4th?

Thanks, any help would be much appreciated!
Nils

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Bob KingPost Author

January 28, 2018 at 11:51 pm

Hi Nils,
You're welcome. The date is actually a little later than than because Sirius and the Sun rise nearly level around the 3rd from so far north. Closer to the 13th.

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Nils M

January 29, 2018 at 12:26 am

Ok, interesting thanks. Do you know if this date would have been a month earlier (mid August) four thousand years ago due to procession of the equinoxes like in Egypt, or would it have taken place at a different date?

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Theo-Wellington

January 30, 2018 at 12:07 pm

Bob
Good article and nice graphics. Really nice section on photography.
No one called these blood moons in recent times until the end times stuff. Wish the social media at S&T would not use this term. I'm going to have people at outreach events now who don't know what a lunar eclipse is as now even NASA calls it a blood moon.
Is there an app for reporting the *actual* color?

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Bob KingPost Author

January 30, 2018 at 11:32 pm

Thanks so much, Theo. I'm not sure if there's an app, but I included the Danjon Scale on my blog here: http://astrobob.areavoices.com/2018/01/30/viewing-tips-and-timetable-for-tomorrow-mornings-total-lunar-eclipse/

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Graham-Wolf

January 30, 2018 at 8:23 pm

Hi Theo!

I think you are referring to the DANJON Index, which is a measure of both the colour and brightness of the totally eclipsed Moon. Sky and Telescope has some nice "leaner" articles on this. Also, try Google + Danjon Index. Some Totally eclipsed moons are blood red, some are even bright orange like glowing coals. The actual DANJON measure is personally subjective, and varies quite a bit from person to person, and also:- from eclipse to eclipse.

In a few hours the Eclipse starts tonight over here in NZ.
We get the whole works and all 76 minutes of Totality. Temps at the moment in the scorching mid 30s Celsius! Also, clear blue skies so far. Great!

BUT.... ~ 14 or 15h UT during the 2nd half of the event, NZ gets whacked hard by tropical cyclone FEHIL..... and it blows and buckets down for days afterward. Let's hope it's a few hours late getting here.....

Theo... you might wish to time the passage of the Earth;'s shadow over prominent lunar craters, as I have done for over 4 decades. Roger Sinnott has an excellent article on this, and a prediction table.. also on this blogsite. Time the passage of the Earth's shadow across the leading edge of the crater in question. This is T1. Then, as it passes over the opposite edge, take another timing, Call this T2. You will end up with a set of IMMERSUON and EMMERSION timings. Try and time to the nearest 5 seconds if you can. You'll need typically a 6 inch 'scope and 200x approx... the important thing here, is to obtain clear close-up views... there's very little contrast at a Full Moon, and use a calibrated stopwatch. Try WWV on 5, 10, 15, 20 MHz.

You may also wish to also time the totality itself! Good luck there. too!
If you have a reasonable Compact digicamera (DSLR is even better) crank out a few shots of the eclipse.... say at 20 minute intervals, I'm sure Bob will be doing so, himself!

Finally, Fred Espenak's NASA Goddard Eclipse Websites are full of very precise prediction data.

Bob... you might also wish to input into this message.
Good luck to all the Astro-Bob readers, out there!

Graham W. Wolf at 46 South, Dunedin, NZ.

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