Today, November 28, 2012, will feature a lunar eclipse that will be visible for much of North America. Today’s eclipse will be of the penumbral variety, meaning that the Moon will not disappear and turn red, but will merely get darker than usual. Still, though, it is an event worth watching if you can.
Unfortunately, many people can’t watch it for a variety of reasons. The good news: the eclipse will be broadcast live online.
The SLOOH Space Cam will be broadcasting about 30 minutes of the eclipse live on its website from 9:15 to 9:45am EST, the time for deepest eclipse. To watch, one can simply go here.
Lunar eclipses occur when the Sun, Earth, and Moon fall exactly into line ion that order. Unfortunately, because the Moon orbits the Earth on a slightly tilted axis, the Moon rarely falls into earth’s shadow, thus becoming eclipsed. Or perhaps this is a good thing as, if there was an eclipse at every Full Moon, eclipses wouldn’t be all that special, would they? Okay, personal opinions aside, every now and then, at a point on its orbit called a “node,” the Moon crosses into the Earth’s shadow, thus resulting in an eclipse.
So, what can one expect to see?
First, the eclipse takes place over the course of several hours. The penumbral phase (the entirety of the eclipse this time) is where the Moon moves into the lightest part of Earth’s shadow, called the penumbra. At this point, one will notice a slight darkening of the Moon. This time, this is all we are going to see, so the next three paragraphs (though informative) need not apply tomorrow night
Iif the eclipse were to be deeper, the partial stages would be next. In the partial phases, the Moon starts moving into the darkest part of the Earth’s shadow, called the umbra. In this phase, the Earth’s shadow will start to eat into the corner of the Moon, eventually coming to the point where the Moon looks like a crescent, but at an otherwise impossible angle. In time, more and more of the Moon will disappear into the Earth’s black shadow until the entire lunar disc is consumed.
In a very deep eclipse, phase 3 is totality. Near the point where the Moon completely disappears into the Earth’s shadow, it will begin to take on a very distinctive, reddish color thanks to the scattering of light rays caused by our atmosphere. Basically, the particles in the air scatters all the colors of the visible spectrum, with the exception of the reds, away into space, thus only allowing the red light to fall on the Moon. Totality can last for around an hour, give or take a few minutes either way. For something interesting, compare the number of stars you can see during totality to the number you can see when the Moon is full. Basically, totality is effectively a Moonless sky.
After totality ends, the Moon will again go through partial phases, becoming more and more exposed as time progresses. In time, the partial stage will end, the second penumbral stage will begin, and the the Moon will eventually go back to normal.
As for visibility, the ad news is that us living in the Cleveland area ()and the rest of the Eastern United States) will not get to see anything as the eclipse will start after the Moon sets. For people living on the West coast, deepest eclipse will be at moon set, so you will have something to see.
As for clouds, be sure to keep an eye on your local weather forecast. For hourly cloud predictions, find a clear sky clock near you.
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