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Comet's 'dust bunnies' to shower Earth



(LifeWire) -- Geoff Chester was just 7 years old when he picked up his dad's binoculars and aimed them at that familiar luminous object casting its glow over the night sky of Fairfield County, Connecticut. Ever since, he's been hooked on stargazing.

A bright Leonid fireball from the meteor shower of 1966 is seen over California. A Geminids shower is expected in December.

"I could see the craters on the moon, and I was like, wow," he said.

Now in his mid-50s and a public affairs officer for the U.S. Naval Observatory in Washington, D.C., Chester is still scanning the heavens. He's in good company; throughout the year there are many opportunities for browsing the great beyond.

Stars and planets

Derrick Pitts, chief astronomer and planetarium programs director of the Franklin Institute in Philadelphia, said there's plenty for amateur star watchers to appreciate.

Although Jupiter rules the summer sky, it begins to fade around late September. By November, the planet Mars makes its way into the evening sky, rising in the east just after sunset, Pitts said. Come December, Mars is at its closest position to Earth, appearing as a rosy, non-twinkling star.

Early risers will be greatly rewarded by the jewels of the morning sky. As November rolls in, Venus, Saturn and Mercury show up about 45 minutes before sunrise.

"The morning sky is a great time to observe because the overnight temperature change typically has removed a lot of humidity and haze," Pitts said.

The fall and winter sky is filled with starry constellations. Cygnus the swan, as it is known in summer and fall, morphs into the Northern Cross on the northwest horizon in December. Cygnus is the main constellation of summer, Pegasus owns the fall, Orion the winter and Leo is king of the spring sky, Pitts said.

Perennial favorite the Big Dipper hangs in the northern horizon in October and by December appears to stand on the tip of its handle.

Meteors

Of the dozen or so annual meteor showers, the Geminids is one of the most spectacular. It will take place in the wee hours of December 14. NASA: Meteor schedule

"The Geminids is really a hot meteor shower," Pitts said. The meteors fall at medium speed, so they're easy to locate, he added.

The Geminids can be seen from anywhere in the Northern Hemisphere, though you'll want to get away from city lights if possible. In truly dark skies, you may be able to see 60 to 120 meteors per hour.

Meteor showers come from comets, concoctions of carbon dioxide, rocks and dirt. A comet eventually warms up in its orbit around the sun and then discards its "dust bunnies," as Pitts called them. Earth cuts through that path and, as the comet dust falls into the heavier atmosphere nearer Earth, the meteors begin to glow.

Finding your way

So how can beginners learn their way around the night sky?

"You get a star map and you look for the obvious stuff: the moon, a planet, Jupiter, Saturn, Venus," Pitts said. "Then you start looking for bright stars. See how much you can see where you are."

Next, use binoculars to see what else you can spot.

Lewis Thomas, corresponding secretary for Amateur Astronomers Inc., a club in central New Jersey, advises looking at the moon in its crescent phases, when more shadows help define the mountain peaks and craters. "The full moon has very little shadow," he said.

"Lean against a building to keep yourself steady," he said. "It makes a world of difference."

Buying a telescope

The kind of telescope to buy depends on where you live and how you're going to use it. If you live in the city, Pitts said, buy a light, portable telescope that you can tote to locations with less surrounding light. If you live outside a city and have the space, you can permanently set up a larger telescope for viewing.

Chester recommends reading "Backyard Astronomy" by Terence Dickinson before you buy a telescope. The book and related Web site include an overview of telescope manufacturers, a guide to eyepieces and filters, as well as tips for using a telescope.

A reflecting telescope about 4 inches in diameter is a good choice, Thomas said. "It will cost about $150," he noted. Anything costing less than that is "junk," in Thomas' opinion. "You're wasting your time with toys."

Some state parks have begun to recognize the dark skies above them as a natural resource for stargazing, Pitts said. Outdoor lighting is regulated, car lights are prohibited and even flashlights are required to have a red filter on them in these parks.

Cherry Springs State Park in north-central Pennsylvania was designated a "Dark Sky Park" in 2000. Others can be found in New York, Georgia, Michigan and New Mexico. For world-class stargazing in the Southwest, you'll find telescopes at observatories open to the public along Interstate 10, nicknamed "Highway to the Stars." E-mail to a friend E-mail to a friend

LifeWire provides original and syndicated lifestyle content to Web publishers. Linda K. Harris is a freelance writer and former lifestyle editor for The Philadelphia Inquirer.

By Linda K. Harris
http://edition.cnn.com/2007/LIVING/wayoflife/11/30/stargazing/index.html

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1 comment:

septiaji said...

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