Your guide to the total lunar eclipse

Eclipse schedule
The eclipse will begin when the moon enters the faint outer portion, or penumbra, of Earth's shadow. 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 delicate shading on the left part of the moon's disk about 20 minutes before the start of the partial eclipse (when the round edge of the umbra, or central shadow, first touches the moon's left edge). During the partial eclipse, the penumbra should be readily visible as a dusky border to the dark umbral shadow.

The moon will enter Earth's much darker umbral shadow at 8:43 p.m. ET Wednesday, which is also 7:43 p.m. CT, 6:43 p.m. MT and 5:43 p.m. PT.

Seventy-eight minutes later the moon is entirely within the shadow, and sails on within it for 51 minutes (about average for a total lunar eclipse), until it begins to find its way out at the lower left (southeastern) edge.

The moon will be completely free of the umbra by 9:09 p.m. PT Wednesday, which is 12:09 a.m. ET Thursday.

The vaguer shading of the inner penumbra can continue to be readily detected for perhaps another 20 minutes or so after the end of umbral eclipse. Thus, the whole experience ends toward 12:30 a.m. for the East Coast (with the re-brightened moon now sloping down along the high arc it describes across the sky), or during the midevening hours for the West.

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For Europe and Africa, the midpoint of this eclipse occurs roughly between midnight and dawn on Thursday morning, and as such the moon will still be well-placed in the western sky. At the moment of midtotality (3:26 UT), the moon will stand directly overhead from a point in the Atlantic Ocean roughly several hundred miles to the northeast of the coast of Suriname.

There will be a partial eclipse of the moon that will be visible across much of Europe and Asia on the night of Aug. 16-17. About 81 percent of the moon's diameter will become immersed in the umbra, leaving only the upper part of the moon visible.

In 2009, there will be four lunar eclipses — one a slight partial, and three others that will be of the penumbral variety. That means that at best only a vague hint of a light shading or smudginess on the moon's disk might be detected, if anything at all.

Not until Dec. 21, 2010, will there be another total lunar eclipse. That one will again favor the Americas.

So although we've had a veritable plethora of total eclipses of late, keep in mind that after Wednesday night, you'll have to wait almost three years for your next chance to see one.

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

This story has been updated by msnbc.com.

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