On Wednesday evening, October 27th, the full Moon will pass through the Earth’s
shadow for skywatchers all across the Americas. The total phase of the eclipse
will last 1 hour and 22 minutes, and the Moon will be conveniently high in the
eastern sky after dark while most people are still awake and about.

In fact, the eclipse occurs during Game 4 of baseball’s World Series, which the
Boston Red Sox and St. Louis Cardinals are scheduled to play that evening in
Missouri. According to astronomer and meteorologist Joe Rao, this is the first
time a total eclipse of the Moon will be visible from a major league ballpark
during a World Series game, and such a coincidence is not likely to happen again
until the second half of this century.

The only slightly problematic area will be near the West Coast of North America,
where the partial phase of the eclipse will begin just a few minutes after
sunset and moonrise while the sky is still bright. But if you have an open view
low to the east, even this situation will only add to the drama. As twilight
fades, westerners will see the shadow-bitten Moon coming into stark view low
above the landscape, and by the time total eclipse begins, the sky will be
getting quite dark and the Moon will be fairly high.

Europe and much of Africa also get a good view of this eclipse, but at a less
convenient time: before dawn on Thursday morning, October 28th.

A total lunar eclipse occurs when the Sun, Earth, and Moon form a nearly
straight line in space, so that the full Moon passes through Earth’s shadow.
Unlike a solar eclipse, which requires special equipment to observe safely, you
can watch a lunar eclipse with your unaided eyes. Binoculars or a small
telescope will enhance the view dramatically.

As the Moon moves into the outer fringe, or penumbra, of Earth’s shadow, it will
fade very slightly — imperceptibly at first. Only when the leading edge of the
Moon is at least halfway into the penumbra is any shading visible at all.

The real show starts when the Moon’s leading edge first enters the shadow’s dark
core, or umbra, and the partial eclipse begins. For the next 1 hour and 9
minutes, more and more of the Moon will slide into dark shadow.

The total eclipse begins when the Moon is fully within the umbra. But it likely
won’t be blacked out. The totally eclipsed Moon should linger as an eerie,
coppery red disk in the sky, as sunlight scattered around the edge of our
atmosphere paints the lunar surface with a warm glow. This is light from all the
sunrises and sunsets that are in progress around Earth at the time.

Each total lunar eclipse is different. Sometimes the Moon looks like an orange
glowing coal, while at other times it virtually disappears from view. Its
brightness depends on the amount of dust in the Earth’s upper atmosphere at the
time, which influences the amount of sunlight that filters around the Earth’s
edges. Because the Moon passes through the northern half of the umbra during
this month’s event, the Moon’s northern edge may remain fairly bright.

After 1 hour and 22 minutes the leading edge of the Moon will emerge back into
sunlight, and the eclipse will again be partial. In another 1 hour and 9 minutes
the last of the Moon will emerge out of the umbra.

A lunar eclipse offers a great chance for either still or time-lapse
photography, especially if you have a long lens or can shoot through a
telescope. See “Observing and Photographing Lunar Eclipses” on
SkyandTelescope.com for tips on how to get good results with film and digital
cameras.

More information about this month’s lunar eclipse appears in the October 2004
issue of Sky & Telescope magazine and the September/October 2004 issue of Night
Sky, our new bimonthly magazine for beginning stargazers.

Wednesday night’s total eclipse of the Moon is the first one visible in North
America since November 8, 2003. The next total lunar eclipse occurs in 2-1/2
years, on March 3, 2007, and favors Europe, Africa, and the Middle East, though
skywatchers on the east coast of the Americas will also see much of it, weather
permitting.

Sky Publishing Corp. was founded in 1941 by Charles A. Federer Jr. and Helen
Spence Federer, the original editors of Sky & Telescope magazine. The company’s
headquarters are in Cambridge, Massachusetts, near the Harvard-Smithsonian
Center for Astrophysics. In addition to Sky & Telescope and SkyandTelescope.com,
the company publishes Night Sky magazine (a bimonthly for beginners with a Web
site at NightSkyMag.com), two annuals (Beautiful Universe and SkyWatch), as well
as books, star atlases, posters, prints, globes, and other fine astronomy products.

Related Articles:

* October’s Ideal Lunar Eclipse http://skyandtelescope.com/observing/objects/eclipses/article_1340_1.asp

* Observing and Photographing Lunar Eclipses http://skyandtelescope.com/observing/objects/eclipses/article_89_1.asp