This lunar eclipse will include an 'impossible' sight

This lunar eclipse will include an 'impossible' sight
Even though sun and moon are 180 degrees apart, you might see them simultaneously

By Joe Rao
updated 12/7/2011 6:15:30 PM ET 2011-12-07T23:15:30

This year's second total lunar eclipse on Saturday morning will offer a rare chance to see a strange celestial sight traditionally thought impossible.

Ringside seats for the lunar eclipse can be found in Alaska, Hawaii, northwestern Canada, Australia, New Zealand and central and eastern Asia. Over the contiguous United States and Canada, the eastern zones will see either only the initial penumbral stages before moonset, or nothing at all.

Over the central regions of the United States, the moon will set as it becomes progressively immersed in the Earth's umbral shadow. The Rocky Mountain states and the prairie provinces will see the moon set in total eclipse, while out west the moon will start to emerge from the shadow as it sets.

The moon passes through the southern part of the Earth's shadow, with totality beginning at 6:06 a.m. PT and lasting 51 minutes.

For most places in the United States and Canada, there will be a chance to observe an unusual effect, one that celestial geometry seems to dictate can't happen. The little-used name for this effect is a "selenelion" (or "selenehelion") and occurs when both the sun and the eclipsed moon can be seen at the same time.

Seeing the impossible
But wait! How is this possible? When we have a lunar eclipse, the sun, Earth and moon are in a geometrically straight line in space, with the Earth in the middle. So if the sun is above the horizon, the moon must be below the horizon and completely out of sight (or vice versa).

And indeed, during a lunar eclipse, the sun and moon are exactly 180 degrees apart in the sky; so in a perfect alignment like this (a "syzygy") such an observation would seem impossible.

But it is atmospheric refraction that makes a selenelion possible.

Atmospheric refraction causes astronomical objects to appear higher in the sky than they are in reality.

For example: when you see the sun sitting on the horizon, it is not there really. It's actually below the edge of the horizon, but our atmosphere acts like a lens and bends the sun's image just above the horizon, allowing us to see it.

This effect actually lengthens the amount of daylight for several minutes or more each day; we end up seeing the sun for a few minutes in the morning before it has actually risen and for a few extra minutes in the evening after it actually already has set.

The same holds true with the moon as well.

As a consequence of this atmospheric trick, for many localities there will be an unusual chance to observe a senelion firsthand with Saturday morning's shadowy event. There will be a short window of roughly 1 to 6 minutes (depending on your location) when you may be able to simultaneously spot the sun rising in the east-southeast and the eclipsed full moon setting in the west-northwest.

Regions of visibility
For places to the east of the Appalachian Range, this will, unfortunately, be a non-event. Although the moon will still be above the horizon when it begins to enter the Earth's shadow at 6:33 a.m. EST, it initially is the penumbral shadow that first contacts the moon.

This shadow is so faint that at least three-quarters of the moon's diameter must be immersed within it before you would have a chance of detecting it visually, either with your naked eyes or using an optical aid. That means, if you live in places such as Boston, New York or Miami, the moon will look perfectly normal as it sets.

But from southeast Ontario, through the Ohio Valley and continuing south to the central Gulf Coast, the upper-left portion of the moon will begin appearing somewhat darker or "smudged" as it begins to disappear beyond the horizon. As you head farther west, the moon's entry into the much-darker part of the Earth's shadow (the umbra) will become evident at 7:45 a.m. Eastern Time or 6:45 a.m. Central.

Across portions of the Upper Midwest, the Nation's Heartland, down into the central parts of Oklahoma and Texas, about half of the setting moon will be immersed in the umbra. The shadow will appear to be creeping almost straight down across the moon's face from its upper limb.

Across the Central and Southern Plains only the lowermost portion of the moon will remain in view as it moves down below the west-southwest horizon. Farther west and north, across the Desert Southwest and High Plains, the moon will rise completely immersed in the Earth's shadow, while for parts of the Intermountain Region, Northern California and the Pacific Northwest, the moon will begin to emerge from the umbra as it sets.

Important facts to consider
In order to observe the selenelion, you should make sure that both your east-southeast and west-northwest horizons are free of any tall obstructions that might block your views of the setting moon or rising sun.

Also, keep in mind that, depending on the clarity of your sky, you might actually lose sight of the moon about 10 or 15 minutes before sunrise thanks to the brightening morning twilight and the moon sinking into any horizon haze (atmospheric "schmutz").

Keep in mind that this holds only for the uneclipsed portion of the moon. Indeed, if the moon is totally eclipsed at moonset, you will probably have to scan the western horizon as the twilight increases in order to detect the moon, which will perhaps resemble a dim and eerily illuminated softball.

If you take a photo or video of the eclipse that you'd like to share with Space.com for a possible story or gallery, please email Tariq Malik at tmalik@space.com or Clara Moskowitz at cmoskowitz@space.com.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy forThe New York Timesand other publications, and he is also an on-camera meteorologist for News 12 Westchester, N.Y.

•Total Lunar Eclipse of June 2011: First Photos
•December 2011 Skywatching Events
•More Night Sky Features from Starry Night Education

http://www.msnbc.msn.com/id/45589117/ns/technology_and_science-space/t/lunar-eclipse-will-include-impossible-sight/
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thanks Sky

cool :)

sky, the article did not mention the redness which i read about somewhere else ...
did you hear about it, also? this from nasa:

Quote :

The action begins around 4:45 am Pacific Standard Time when the red shadow of Earth first falls across the lunar disk. By 6:05 am Pacific Time, the Moon will be fully engulfed in red light. This event—the last total lunar eclipse until 2014—is visible from the Pacific side of North America, across the entire Pacific Ocean to Asia and Eastern Europe

http://science.nasa.gov/science-news/science-at-nasa/2011/02dec_lunareclipse/

global visibility map ---->
http://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2011-Fig06.pdf

hi guys

i think this is going to have a bunch of stories..you know end of the earth and everything..becasue of seeing the sun and moon at the same time..should be interesting

hippie if you get to see it..let us know how it was...cause where i am we aren't going to see much

otter, i plan to set alarm and be up on roof of sam's apt. building
where i should be able to see 360 degrees, so east as sun rises
and west as moon sets .... of course, we may have fog, which
will block a lot, and i may roll over and go back to sleep when
alarm goes off, but it's a plan i would like to follow thru on .....
i will have camera with me

...and its completely overcast here...can't see any sky at all, and probably wont tomorrow either :/

stal wrote:

...and its completely overcast here...can't see any sky at all, and probably wont tomorrow either :/

And thats my worry all in one

We have the best bloody viewing position on the east coast for this one and the weather gets all screwed up

its nearly 5am and i can't see fcuk all of the sky...

Soo soo tempted to just crash out on the couch lol

i hope the skies cleared up for you guys

here's my favorite link
http://www.shadowandsubstance.com/

and more from

space dot com

The last eclipse of 2011, a total lunar eclipse, will occur early Saturday morning (Dec. 10). Although best placed for observers in Australia and eastern Asia, part of the eclipse will be visible from the west coast of Canada and the United States.

A total lunar eclipse occurs when the Earth passes between the sun and the moon, casting the moon in shadow. The last such eclipse took place in June 2011.

For observers in North America, this eclipse will happen just before dawn Saturday morning. To see it, stay up late Friday night or get up early Saturday morning. Alaska will see all of the eclipse, British Columbia most of it, the views will decrease as you move south and east from there.

"From roughly Arizona to the Dakotas, the moon sets while it's still totally eclipsed," writes Sky & Telescope magazine. "In the Central time zone the moon sets while still only partially eclipsed, before the total stage even begins. And those farther east miss out completely."

The eclipse will begin at 3:33 a.m. PST, when the faint outer penumbral shadow touches the moon. The eclipse will be obvious by 4:45 a.m., when the dark umbral shadow begins its trip across the moon's face. The total eclipse phase will start at 6:06 a.m. and last for 51 minutes.

In Sydney, the eclipse will begin at 10:33 p.m. Saturday evening and last most of the night. Totality is from 1:06 a.m. until 1:57 a.m. local time.

It's difficult to predict in advance how dark any particular lunar eclipse will be. It’s extremely rare for the moon to disappear completely because some sunlight always leaks past the Earth through the twilight zones.

Because this light is coming from countless sunsets on Earth, it is usually tinged reddish in color. If cloud cover on Earth is dense, very little light gets through, and we get a very dark eclipse.

Because this eclipse will be low in the western sky in North America and low in the south in Australia, there should be plenty of photo opportunities.

If you take a photo or video of the eclipse that you'd like to share with SPACE.com for a possible story or gallery, please email Tariq Malik at tmalik@space.com or Clara Moskowitz at cmoskowitz@space.com.

This article was provided to SPACE.com by Starry Night Education, the leader in space science curriculum solutions. Follow Starry Night on Twitter @StarryNightEdu.

it is now just after 11pm and i have alarm set for 5am so i should
be able to see the partial move into full .... have the camera setting
on "fireworks" and have my warm clothes ready - will be shooting
from the roof of a 14 story building, fairly unobstructed and there is
no fog yet so the only thing is whether the lights from the city will
minimize the effect, we'll see ... and of course once i hear the alarm, could
change my mind .... but i don't think so

I saw it from here this morning, as the moon was setting over the Black Hills in South Dakota. I didn't see any redness but it got a bit orangy as it set. The shadow of the earth came down from the top, thing is after the recent snow I've noticed how glittery it is in the moonlight

ahh Soul Sis..i'm jealous
we had overcast skies..not like we were going to see much anyway..but DANG...

here's some pic's that are posted elsewhere


http://photoblog.msnbc.msn.com/_news/2011/12/10/9348533-goodnight-moon-total-lunar-eclipse-wows-the-world?
Goodnight, Moon: Total lunar eclipse wows the world


A lunar eclipse is seen framed within Turret Arch at Arches National Park, Dec. 10, near Moab, Utah. Saturday's lunar eclipse, resulting from the earth's position between the moon and sun, was forecasted to be the last of its kind until April 2014.


This photo combination shows the different stages of the moon during a lunar eclipse as seen from the Griffith Observatory in Los Angeles, Dec. 10.

more at above link


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vid here but i can't seem to get it to copy..sorry
here's where to look
http://www.space.com/13892-total-lunar-eclipse-dec-10-moon-skywatching-tips.html

about half way down

hope hippie got up

Well I, and I guess Biggles also had a great light show, that did not include the Moon

So nice all the same to get these spring thunderstorms again like I grew up with when I was a wetter.

ok, here we go .... i am still learning to use the camera
so please do not judge too harshly ... most shots i got
were blurry beyond reason, but when i sat camera on a
little wall, i got better results .... i chose 3 for you, the first
is around 5:30, the shadow is creeping from the top, not quite
halfway there yet and i am fussing with camera settings:


this next one, i like, it's almost full now ....


after this, i watched a while longer, but was getting cold, so went inside ...
fyi, it did not appear as "red" with the naked eye, only with the camera ....

definitely need a little tripod in the future ....

WOW! not bad sis.
You've got the hang of that camera, I'd say.

Nice one Hippy !

Not sure of which camera you have but keep persevering! I got lazy with my little canon and didnt quite follow up the rules to getting a good moon shot, and in saying so it is possible to get a half decent moon shot with non professional equipment.

hey Hippie..good shots..thanks....

what i have found to work for me is a tripod and turn off the flash
and if it's cold and the camera takes that extra second or two..it mostly blurs..

this one is lightened one shade to see the trees..i was waiting for that asteroid to go in front of the moon..hah..never did see it
and that bright light is jupiter

SoulSister wrote:

WOW! not bad sis.
You've got the hang of that camera, I'd say.

thanks, sis!
(although i did not post any of the other FORTY (40!) shots i tried .....)

sky otter wrote:

hey Hippie..good shots..thanks....

what i have found to work for me is a tripod and turn off the flash
and if it's cold and the camera takes that extra second or two..it mostly blurs..

this one is lightened one shade to see the trees..i was waiting for that asteroid to go in front of the moon..hah..never did see it
and that bright light is jupiter

thanks and welcome, otter - i did not realize the temperature
made any kind of difference ... as for your asteroid watch ... is
that a "shooting star" above moon on the left?

cool pics :)

Couldn't see a thing here, was raining all night.

shooting star..nah , prabably a jet..but it could be... i didn't even see that..good eye..

i can't speak about all digitals and the cold but my cheapy acts like that..
like anything it's trail and error stuff..

it was overcast here that night - the night before and after..very clear...really ticks ya off
and it seems to happen to sky events around here anymore..sure makes you go into conspiracy mode

Fantastic photo's! It's been raining non stop where I am :(