Albany Herald

ALBANY, Ga. -- For those who have the right equipment to work with, astronomy fans will get to see a rare event Tuesday evening.

The transit of Venus, the passage of Earth's neighbor in the solar system across the sun, will be visible from North America at sunset. The next such event will not occur until December 2117, according to www.transitofvenus.org.

The phenomenon takes place every eight years in time frames spaced more than a century apart. Prior to 2004, the last transit was in 1882.

For as rare as the event is, experts say stargazers shouldn't be looking at it without a telescope that includes a solar filter. The event will begin here Tuesday evening and continue through the next several hours.

"You won't see the complete transit because the sun will be down," said Jim Friese, staff astronomer with the Thronateeska Heritage Center. "Unless you've got decent equipment, don't try to take a look at it. The solar filter is a must."

Thronataeeska will be unable to host a viewing because the facility currently lacks the proper equipment. There are plans to get such equipment, but it will not be available in time for the transit, Friese said.

Planetary transits have helped advance the study of astronomy, specifically as it pertains to learning more about the atmospheric elements of the planet in question, experts say.

"It gives us a chance to study the planet's atmosphere through the sun's light coming through it," Friese said. "We know the chemistry of the sun, so when we filter out those elements, we (learn more about the planet).

"We do this with planets around other stars. It gives us a standard model to work from."

Such events have also stirred up more interest in astronomy in general, Friese said.

"It brings more astronomy issues to public awareness," he said. "(It has also brought forth) outreach programs to get people interested in science."

The transit of Venus takes place when the planet passes across the disk of the sun. Venus, orbiting the sun "on the inside track," catches up to and passes Earth. It appears as a small dot in the foreground moving left to right across the sun.

North America and Central America will be able to see the transit in progress at sunset on Tuesday. Most of South America and western Africa will be unable to see it at all, while most of Europe, the Middle East and parts of Asia will be able to see the transit in progress at sunrise Wednesday.

Eastern Asia and most of Australia will be able to see the transit in its entirety.

Other astronomical sights are also taking place this year. NASA's website indicates that a partial lunar eclipse will take place today, although the eastern United States is not expected to get the most ideal view. The website also says a total solar eclipse will be visible primarily over the south Pacific Ocean on Nov. 13, followed by a penumbral lunar eclipse roughly two weeks later that will not be visible on the U.S. Eastern Seaboard.