For a few hours on the night of Dec. 20-21, the attention of tens of millions of people will be drawn skyward, where there will hang a mottled, coppery globe—our moon—completely immersed for a while in the long, tapering cone of shadow cast out into space by our earth. If the weather is clear, favorably placed sky watchers will have a view of one of nature's most beautiful spectacles: A Total Eclipse of the moon.

Unlike a total eclipse of the sun, which often requires a long journey to the path of totality, those of the moon can usually be observed from one's own backyard. The passage of the moon through the Earth's shadow is equally visible from all places within the hemisphere where the moon is above the horizon.

The total phase of the upcoming event will be visible across all of North and South America, as well as the northern and western part of Europe, and a small part of northeast Asia including Korea and much of Japan. Totality will also be visible in its entirety from the North Island of New Zealand and Hawaii—a potential viewing audience of about 1.5 billion people. This will be the first opportunity from any place on earth to see the moon undergo a total eclipse in 34 months.

Stages of the Eclipse

There is nothing complicated about how to view this celestial spectacle. Unlike an eclipse of the sun which necessitates special viewing precautions in order to avoid eye damage, an eclipse of the moon is perfectly safe to watch. All you'll need to watch are your eyes, but binoculars or a telescope will give a much nicer view.

The eclipse will actually begin when the moon enters the faint outer portion, or penumbra, of the earth's shadow a little over an hour before it begins moving into the umbra. The penumbra, however, is all but invisible to the eye until the moon becomes deeply immersed in it. Sharp-eyed viewers may get their first glimpse of the penumbra as a faint "smudge" on the left part of the moon's disk at or around 1:15 A.M. Eastern Time or 10:15 P.M. Pacific Time (on Dec. 20).

The most noticeable part of this eclipse will come when the moon begins to enter the earth’s dark inner shadow (called the umbra). A small scallop of darkness will begin to appear on the moon's left edge at 1:33 A.M. Eastern Time or 10:33 P.M. Pacific Time (on Dec. 20).

The moon is expected to take 3 hours and 28 minutes to pass completely through the umbra.

The total phase of the eclipse will last 72 minutes beginning at 2:41 A.M. Eastern Time or 11:41 P.M. Pacific Time (on Dec. 20). At the moment of mid-totality (3:17 A.M. Eastern Time/12:18 A.M. Pacific Time), the moon will stand directly overhead from a point in the North Pacific Ocean about 800 miles (1,300 km) west of La Paz, Mexico.

The moon will pass entirely out of the earth's umbra at 5:01 A.M. Eastern Time/2:01 A.M. Pacific Time and the last evidence of the penumbra should vanish, about 15 or 20 minutes later.

Only the Shadow Knows the Moon’s Color

Although astronomers do not expect to gain new astronomical insights from the eclipse, lunar eclipses vividly reflect the overall state of the earth’s atmosphere. Under normal weather and atmospheric conditions, as the moon slides into the shadow of the earth, its normal yellow-white color changes into a still-visible but dull coppery-red at the height of the eclipse. Since the earth's shadow is cone-shaped and extends out into space for some 844,000 miles (1,358,000 km), sunlight will be strained through a sort of “double sunset,” all around the rim of the earth, into its shadow and then onto the moon.

However, because of the recent eruptions of the Mt. Eyjafjallajökull volcano in Iceland last spring and the Mt. Merapi volcano in Indonesia in October, one and possibly two clouds of ash and dust might be currently floating high above the Earth. As a result, the moon may appear darker than usual during this eclipse; during totality, parts of the moon might even become black and invisible.

Or . . . the moon might wear its normal eclipse cloak of a deep red or a coppery-hue or take on still other colors (orange, chocolate brown or gray). Color possibilities are unpredictable and that it is impossible to tell exactly how much light the earth’s atmosphere will refract as its shadow creeps across the moon. Cloud cover and other atmospheric conditions may also affect the visibility and coloration of the Moon.

In short: we’ll all just have to wait for eclipse night and see what actually happens.

At mid-totality, from rural locations far from city lights, the darkness of the sky is impressive. Faint stars and the Milky Way will appear, and the surrounding landscape will take on a somber hue. As totality ends, the eastern edge of the moon begins to emerge from the umbra, and the sequence of events repeats in reverse order until the spectacle is over.

Past and Future

The last total lunar eclipse occurred on Feb. 20-21, 2008 and was visible from most of the Americas, as well as Europe, much of Africa and western Asia. In 2011 there will be two total lunar eclipses. The first, on Jun. 15 will be visible primarily from the Eastern Hemisphere and will have an unusually long duration of totality lasting one hour and 40 minutes. Another total lunar eclipse will occur on Dec. 10 and will be visible over the western half of North America before moonset. For the next total lunar eclipse that will be visible across all of North America, we must wait until Apr. 14-15, 2014.

The Leonid Meteor Shower has long passed us by, but that doesn’t mean that there aren’t any good meteor displays to look forward to. In fact, one of the best is just around the corner, scheduled to reach its peak during the early hours of Tuesday, Dec. 14: The Geminid Meteors.

The Geminids get their name from the constellation of Gemini, the Twins. During the overnight hours of December 13-14—the night of this shower’s maximum—the meteors appear to emanate from a spot in the sky near the bright star Castor in Gemini.

Should the sky be clear where you live early Thursday morning, you'll have an opportunity to catch a glimpse of the annual Leonid Meteor Shower. A decade ago, this was a truly exciting event to watch, with the prospects of seeing more "shooting stars" in a single night than you might have previously seen in your entire life.

But the circumstances were different a decade ago.

The Leonids are particles of dust ejected from the nucleus of Comet Tempel-Tuttle. Back in 1998, when the comet swept around the Sun, it was accompanied by several dense trails of this dusty debris. Since the comet's orbit nearly intersects the Earth's in mid-November, when our planet crossed paths with those dense dust trails, the result were meteors falling at rates in the hundreds, even thousands per hour.

But the comet has long since moved back out into the depths of space and has taken those dense dust trails with it. So now, when we cross paths with the comet orbit in mid-November, there isn't much dust to interact with.

So the pickings this year are slim with probably not much more than a dozen meteors per hour appearing at their peak on Thursday morning.

What's worse, the Moon will be approaching Full, which means it will light up the sky and squelch many of the fainter Leonid streaks. However, that brilliant Moon will set around 3:45 a.m. on Thursday; dawn will break at around 5:15 a.m. If you want to try and see anything, then you should target those 90-minutes; that's when you'll get your best shot.

It might actually be worth getting up to take a look, since every once in a while with the Leonids, there will come an outstandingly brilliant meteor known as a fireball. Perhaps along its flight, a fireball will silently explode in a fiery flash of light. Such meteors are called bolides. And the resultant trail might hang in the sky for many seconds or minutes. I saw just such and photographed just such a meteor from Pennsylvania back in 1996.

Just the sight of a singular object like THAT can make getting up early on a chilly November morning worthwhile. If you're curious enough to get up on Thursday to take a look, remember that the best time will be between moonset and the break of dawn: 3:45 to 5:15 a.m. The Leonids will appear to dart out from the "Sickle" of Leo, a backwards question mark pattern of stars, which will be high in the southeast sky. Don't expect to see much, especially if you live in an area with lots of bright lights or tall obstructions. Even under a dark country sky, you might have to wait five or six minutes between meteor sightings.

I would also recommend that you bundle up warmly. . . perhaps lie down on a long lawn chair.

In December, we'll have two super sky events to look forward to: The Geminid Meteor Shower (which is about 10 times better than the Leonids) and a Total Lunar Eclipse!