Meteors, sun, moon to star in double feature

Meteor streaks over Japan's Mount Fuji in November in this long-exposure photo.

By Richard Stenger
CNN Sci-Tech

(CNN) -- In a rare lineup of celestial wonders this week, a colorful meteor shower will peak the night before an annular solar eclipse.

The Geminids, known for their graceful, slow, bright and yellow trails across the sky, have gradually built up in intensity in recent days.

When the annual meteor shower puts on its greatest display late Thursday and early Friday, the complete absence of moonlight will offer sky watchers ideal viewing conditions.

Perhaps more than 100 meteors might be seen each hour during the peak in some locations. For observers in the Americas, Africa and Europe, astronomers predict the storm will peak between 11 p.m. and dawn local time. For those who cannot stay up that late, a preview show shortly after sunset might be worth checking out.

"You won't see many meteors then, but the ones you do will likely be beautiful Earthgrazers," said NASA scientist Bill Cooke, referring to disintegrating meteoroids that fly over the horizon nearly parallel to the atmosphere and are characterized by long, vivid trails.

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For Australians and east Asians, the main event should take place before local sunrise on Friday and again after sunset on the same day, according to Spaceweather.com, a NASA-affiliated Web site.

The meteors are so named because they seem to originate from the constellation Gemini. Geminds can appear anywhere in the sky but their trails usually point back to their parent constellation.

For best viewing, head to remote areas with dark skies, far away from artificial light sources. For those in North America, make sure to bring plenty of warm clothes, blankets and lawn chairs.

Solar light show

The moon takes a bite out of the sun in this 1997 partial solar eclipse.

On Friday, another celestial spectacle will take place over most of the Americas -- a solar eclipse. The eclipse will be annular, meaning the disk of the moon will seem slightly smaller than the sun.

The moon will pass directly in front of the sun but a bright ring of sunlight will remain visible to those directly underneath the annular eclipse path.

The center of the annular eclipse shadow will race over the Pacific Ocean and briefly cross land just before sunset in Costa Rica and Nicaragua, where eclipse chasers have gathered for the event.

The partial phases of the eclipse can be seen over most of North America. In the East, it will occur just before or right at sunset. In the West, it will happen late in the afternoon.

Astronomers caution that observers should never look directly at a partial or annular eclipse, but rather use special optical filters or projection devices.