Nature often provides us spectacles, some dangerous and exciting, some beautiful and calming.

If Mother Nature cooperates, one of those beautiful and calming spectacles is expected to be visible in the sky tonight. If it's not too cloudy, Mercer County residents can watch the full moon dim into a dark, ruddy orb as it drifts through Earth's shadow.

The start of the eclipse will begin at 6:33 p.m., said local astronomer Ted Pedas. The total eclipse will begin at 8:06 p.m. and end at 8:31 p.m., he said.

"It's going to be a very, very exciting show for locals to go out and see," Pedas said. "It's rare that we have a total eclipse that's so visible so early in the evening."

Pedas, director of Farrell Area School District's Ted Pedas Planetarium, said eclipses usually occur in the middle of the night and people have to set their alarm clocks to watch them.

The total eclipse will be very short, only about 25 minutes, while many can last as long as 1 hour and 40 minutes, Pedas said.

This heavenly happening is unusual not only because it's so early in the evening, but also because it's the second lunar eclipse this year, Pedas said. There was a total eclipse in May.

"It's only every few years, about every three years, that we get an interesting total eclipse for the Shenango Valley," Pedas said. "It's only once a decade or longer that we get one that's nice and early in the evening."

Unlike eclipses of the sun, which can damage viewers' unprotected eyes, lunar eclipses are safe to watch with the naked eye or binoculars.

"It's a fun thing to take the family out," Pedas said. He said everyone will have to keep their fingers crossed for good weather.

Depending on how much pollution is in the sky because of volcanic eruptions, viewers may be able to see a very faint outline of the moon during the total eclipse, Pedas said.

Total lunar eclipses come in many colors, from dark brown and red to bright orange, yellow and even gray, depending on how much dust and clouds are in the Earth's atmosphere at that time, said Stephen Maran, a spokesman for the American Astronomical Society.

Lunar eclipses have played a major role in history, Pedas said.

He said when Christopher Columbus ran out of food on a trip, he went to the natives but they weren't very friendly. Columbus, who knew of an impending eclipse, told the natives he would take away their moon. When the eclipse came, the natives thought Columbus was a god and brought him food, Pedas said.

In ancient times, the phenomenon was believed to be caused by some unseen monster bloodying the moon, an omen of disaster.

Eclipses may have been mystical then, but now people understand the science behind them. Pedas said they prove the mechanics of the solar system as the moon comes into the shadow of the earth.

More information about the sky above Mercer County can be found on the Ted Pedas Planetarium Web pages at: www.nauticom.net/www/fasdhs/Planetarium/Pages/Tpplanetarium.html.