Although the eclipse will officially start when the Moon makes first contact with Earth’s outer shadow, at 05:29 UT /12:29 am ET / 9:29 pm PT, totality will not begin until Luna begins its 72-minute passage through Earth’s inner shadow, at 07:40 UT / 02:40 ET / 11:40 PT.

Lunar eclipses are best observed with the unaided-eye, but a standard pair of binoculars will help to intensify totality’s coppery red color.  Photographs are also very effective in bringing-out an eclipse’s dramatic colors.  If you’re new to night sky or eclipse photography, these Basic Photography Tips explain the three technical elements of an image and this Lunar Eclipse Exposure Guide suggests basic settings for eclipse photography.  You might also like to try a multi-exposure image, to illustrate the progression of the eclipse.

Add some evaluation fun to your evening, by using the Danjon Scale to determine the Moon’s appearance and brightness during totality, or engage in more in-depth analyses as described in Daniel Fischer’s “What They Don’t Tell You About Tonight’s Total Lunar Eclipse.”

Share your observations with others!  Spaceweather.com is encouraging observers to submit their Danjon Scale ratings, to assist climate scientist Richard Keen with his Lunar Aerosol Climate Experiment.  JPL has a Lunar Eclipse Flickr group, where you can share your eclipse images.  You can also share your observations on Twitter, by including hashtags like #LunarEclipse, #skywatch, and #moonwatch with your tweets.

As the Moon becomes immersed in shadow, try identifying various craters and Apollo landing sites, as well as neighboring celestial objects.  Luna will spend the evening in Taurus, near the borders with Gemini and Orion.  This region includes such deepsky favorites as Orion’s Nebula; Messier clusters M35, M36, M37, and M38; Monoceros’ Cone Nebula; and Taurus’ Pleaides and Hyades clusters.  Some brighter stars in the area include Betelgeuse, Aldebaran, Procyon, Pollux and Castor, Capella, and Alnath and Alhena.  There’s also the Ursid Meteor Shower, which may be more apparent in the darkness of Totality!

While December’s Full “Long Night” Moon doesn’t officially occur until December 21st, Luna will be “full” when it rises Monday evening (else we couldn’t have a lunar eclipse!)  A rising full Moon is always a pretty thing to see, so watch for it on your ENE horizon around 4:30pm, or about 30-minutes before sunset.

If your skies are too cloudy, you can observe the eclipse via live image streams and webcasts:

Astroguyz’s Flickr PhotoStream

ChrisAstro on JustinTV

Columbus State University’s Coca-Cola Space Science Center

NASA-hosted live chat and video feed!

Night Sky Network (an Astronomers Without Borders list of nine different broadcasters)

SLOOH Online Observatory (registered members only)

AFM*Radio will be discussing the eclipse tonight!  You can tune in by clicking the “Listen Now” button on their home page, or via iTunes, where you’ll find them as the sixth station listed in the News/Talk Radio section.

FUN FACTS:

This month’s Total Lunar Eclipse is the first in nearly three years – our last total event was in February 2008.

This year’s Total Lunar Eclipse nearly coincides with the Solstice, which will occur on December 21 at 23:38 UT / 6:38pm ET / 3:38pm PT.  While a “solstice eclipse” is not rare, it is an infrequent enough occurrence to warrant special mention.

There will be two Total Lunar Eclipses next year, in June and December, the latter of which will be visible in parts of the U.S.

The outer and inner shadows, through which the Moon passes, are known as the penumbra and umbra.

A Total Lunar Eclipse, or totality, occurs when Luna is completely immersed in Earth’s inner shadow.

There are other types of lunar eclipses, including a penumbral eclipse, when the Moon passes through Earth’s outer shadow, and a partial eclipse, when Luna passes through only a portion of Earth’s inner shadow.  The most dramatic, and more elusive, of eclipses is a selenelion, or horizontal eclipse, when any lunar eclipse can be viewed opposite the Sun, such as during sunrise or sunset.

The duration of an eclipse varies according to Luna’s path through Earth’s shadow.  The maximum time an eclipse can last, from penumbra entrance to penumbra exit, is 3-hours, 40-minutes.  The longest totality, when Luna passes through the very center of Earth’s shadow, is 1-hour, 40-minutes.  Partial eclipses are much shorter, particularly when only a small portion of the Moon slips through the top or bottom of Earth’s outer shadow.

Lunar eclipses occur 2 to 3 times a year and are visible over an entire hemisphere. (Solar eclipses occur 2 to 5 times a year, but are visible along a path not more than 167-miles wide.)

Total Lunar Eclipses are always preceded or followed by a Solar Eclipse, with exactly two weeks between the two.  This month’s Lunar Eclipse will be followed by a Partial Solar Eclipse on January 4, 2011.

Lunar eclipses follow a long-term rhythm, wherein each eclipse’s characteristics are repeated every 18 years, 11 days, 8 hours (223 synodic months.)  This month’s eclipse is #48 of Saros 125, a series of 72 eclipses, beginning on July 17, 1163 and ending on September 9, 2443.

*SOURCES:

Astroguyz – Breaking News for Sky Aficionados - Dan Durda’s Exploring the Apollo Landing Sites - David Bradley’s Science Base - Digital Cameras Help – Ewan Bryce - Farmer’s Almanac - Keith’s Moon Page - Mr. Eclipse – MSNBC - NASA/GSFC - Night Sky Hunter - Shadow and Substance - Sky and Telescope - Space.com - Spaceweather.com