Watch the Moon Take a Bite from the Sun

For the second time in the past year, the moon’s shadow is poised to sweep
over North America. On the afternoon of December 14, the moon will pass in
front of the sun and block part of our star from view. If skies are clear,
people across most of the United States and much of Canada will have the
opportunity to witness this celestial spectacle.

Unlike the Christmas Day eclipse of 2000, this year’s eclipse promises
better views the farther south you live. The moon takes no more than a
nibble out of the sun across southern Canada. Approximately 20 percent of
the sun will be hidden from view on an arc that runs from Southern
California to around Chicago. Forty percent of the sun will disappear along
the Texas Coast and in the Southeast up to the Atlanta area. And at least
half of the sun will be covered as seen from Florida.

The moon’s shadow will be moving from west to east across the continent.
The eclipse occurs during the early afternoon along the West Coast and ends
well before sunset. From the Midwest, the sun sinks below the horizon just
as the eclipse concludes. In the eastern half of the United States, the sun
sets while still in eclipse. Only observers in eastern New England and
northern and eastern Canada will miss out on the eclipse entirely.

For those who happen to find themselves under thick clouds – a distinct
possibility in mid-December – the wait for another solar eclipse won’t be
long. “Amazingly, North America will play host to a partial eclipse of the
sun next June 10,” says David J. Eicher, managing editor of Astronomy
Magazine. “It’s highly unusual to have three eclipses visit the same region
of the globe in a span of just 18 months.”

Although people in the United States and southern Canada will get a nice
view of the December 14 eclipse, the show improves dramatically in Mexico
and Central America. The moon covers three-quarters of the sun from
southern Mexico and nearly all of it along a narrow swath of Costa Rica and
Nicaragua. If the moon were slightly closer to Earth and thus a little
larger in the sky, the eclipse would be total. Instead a narrow ring of
sunlight will remain visible, creating what’s known as an annular eclipse.

Unfortunately, the opportunity for eclipse viewing also brings risk.
“Watching an eclipse poses more danger than any other kind of skygazing,”
warns Richard Talcott, Astronomy’s senior editor. “The sun shines so
brightly that it can blind anyone who looks at it directly – even when the
moon hides most of it from view.” Even worse, the damage happens both
quickly and painlessly.

That doesn’t mean you shouldn’t watch the eclipse, just that you need to
take the proper precautions. One safe method is to view the sun indirectly
by projecting its image. You’ll need two pieces of white cardboard, some
aluminum foil, tape, and a stick pin. Cut a hole in one piece of cardboard
and tape the foil over the hole. Then use the pin to poke a tiny hole
through the foil. During the eclipse, stand with your back to the sun and
let sunlight pass through the pinhole and onto the second piece of
cardboard, where an image of the eclipsed sun will appear. If any trees or
bushes in your area still have their leaves, the openings among the foliage
will act as pinholes and project hundreds or thousands of eclipse images
onto the ground.

You can view the eclipse directly by using a safe solar filter. A #14
welder’s glass works fine – look for it at a welding supply store. Mylar or
metal-on-glass filters sold through astronomy equipment suppliers will also
allow you to view the eclipse safely.

You should never use a so-called “sun filter” that screws into the eyepiece
of a telescope. Also avoid using sunglasses, smoked glass, photographic
film, black plastic garbage bags, Mylar candy wrappers, or photographic
neutral density filters. Although these materials may limit the amount of
visible radiation that passes through, they do little or nothing to stop
the equally dangerous infrared radiation.

Note to editors: An illustration showing the amount of eclipse coverage
across North America, a table giving the local time and magnitude of the
eclipse for various cities, and eclipse images can be found at Astronomy
magazine’s website at http://www.astronomy.com/content/static/pressroom/.

Contact: Richard Talcott, Astronomy Magazine

Phone: 262-796-8776 ext. 566

e-mail: rtalcott@astronomy.com