A total eclipse of the Moon will enchant skywatchers
across almost all of North and South America during the
evening of May 15-16, 2003. For observers in the eastern
United States and Canada, southern Mexico, and all of
Latin America, the eclipse will be visible from start to
finish. For most North American observers west of an
imaginary line that connects Green Bay, Wisconsin with
Brownsville, Texas, the early stages of the eclipse will
take place before the Moon rises, but the Moon will be
visible during the most dramatic stages, when the eclipse
reaches totality.

Lunar eclipses can only occur during the Full Moon when
the Moon moves into Earth’s shadow. This eclipse
“officially” begins at 9:05 p.m. EDT (6:05 p.m. PDT) on
May 15. That’s when the Moon enters the outer portion of
Earth’s shadow, known as the penumbra. But most
observers will not notice any changes on the Moon until
about 9:45 p.m., when the eastern part of the Moon starts
darkening. This early phase of the eclipse is known as a
“penumbral eclipse.”

The beauty of the eclipse will become readily apparent at
10:03 p.m. EDT, when the Moon enters the inner, darker
part of Earth’s shadow, the umbra. At this point, the
Moon is in “partial eclipse,” and a sliver of darkness on
its eastern edge will be noticeable even to the most
casual observer. The total eclipse, which begins when the
Moon is fully inside the umbra, lasts from 11:14 p.m. EDT
to 12:07 a.m. EDT on May 16. The Moon will again be in
partial eclipse until it leaves the umbra at 1:17 a.m. EDT.
The final penumbral phase of the eclipse ends when the
Moon makes last contact with the penumbra at 2:15 a.m.
EDT.

Even though Earth’s shadow is larger than the Moon, the
Moon is still visible when it is totally eclipsed, making it a
grand spectacle easily noticeable to anyone with a clear
sky and an unobstructed view. Earth’s atmosphere filters
out the Suns blue light by scattering it, and it refracts
some of the Sun’s red and yellow light, which strikes the
Moon and often casts our neighboring world in an eerie,
orangish glow.

“What’s really neat about total lunar eclipses is that
every one is different. The color of the Moon varies from
eclipse to eclipse, depending on how much dust and other
aerosols have been recently injected into the atmosphere
by volcanic eruptions and forest fires,” says Robert
Naeye, editor of Mercury magazine, which is published by
the Astronomical Society of the Pacific (ASP).

“Based on the depth of the eclipse and the fact that we
haven’t had any major volcanic eruptions recently, I’d
guess the color will be orange to bright red,” adds
astronomer and eclipse authority Fred Espenak of NASA’s
Goddard Space Flight Center. Espenak maintains a website
of eclipse information and photos at www.MrEclipse.com.

“Total lunar eclipses are fascinating to watch from start
to finish as the Moon darkens and as its color changes
almost minute by minute,” says Naeye. “And a great
thing about lunar eclipses is that they are totally safe to
watch, and no optical aid is needed. Telescopes and
binoculars can provide dramatic views of the eclipsed
Moon, particularly by enhancing the colors. But the only
things you need to enjoy the eclipse are a clear sky and
an unobstructed view.”

An unobstructed line of sight will be critical. At the time
the eclipse starts for observers in the United States and
Canada, the Moon will be very low in the southeastern
sky, so people should find a location where their line of
sight is not blocked by buildings, trees, or mountains. The
Moon will rise higher as the eclipse unfolds, and will
settle in the south-southwestern skies as the eclipse ends
in eastern North America.

This eclipse will not be visible in Alaska or extreme
northwestern Canada, and observers in Hawaii will only
catch its final stages. Observers in Europe, the Middle
East, and most of Africa will be able to watch the early
stages of the eclipse, but the Moon will set before the
eclipse has run its course.

“The May 15-16 lunar eclipse is the first really good
lunar eclipse visible over North America since January
21, 2000,” says noted astronomer and author David H.
Levy, who is a member of the ASP’s Board of Directors.
The next total lunar eclipse visible in North America will
occur on November 9, 2003.

Contact local amateur astronomy clubs, science museums,
or planetariums to see if they are offering public viewing
sessions for the eclipse. Publishable photos of past lunar
eclipses, and diagrams of the May 15/16 eclipse, can be
downloaded free of charge at this ASP website:
www.astrosociety.org/news/lunarpr03.html. The photos
and diagrams were provided by Fred Espenak and by
Phil Harrington, author of the book “Eclipse! The What,
Where, When, Why & How Guide to Watching Solar &
Lunar Eclipses.” Please credit Fred Espenak and Phil
Harrington if you publish or broadcast their images.

For more information about this eclipse, including
diagrams for time zones in North America and Europe,
visit Fred Espenak’s website at:
http://sunearth.gsfc.nasa.gov/eclipse/extra/TLE2003May15.html.
For information on how to photograph the
eclipse, visit www.MrEclipse.com/LEphoto/LEphoto.html.

The nonprofit Astronomical Society of the Pacific was
founded in 1889 in San Francisco and is still
headquartered there today. The ASP has since grown into
an international society. Its membership is spread over
all 50 states and 70 countries and includes professional
and amateur astronomers, science educators of all levels,
and people in the general public. The ASP publishes the
bimonthly Mercury magazine for its members, a technical
journal for professional astronomers called Publications
of the Astronomical Society of the Pacific, and an on-line
teachers’ newsletter. The ASP also coordinates Project
ASTRO, a national astronomy education program. The
Society produces a catalog and website of extensive
astronomy-related products for educators and the public.