GALETON - As Venus makes its journey across the sky on Tuesday, the distant planet actually will be visible in the daylight hours as it glides across the sky.
The planet will pass between the earth and the sun and will look like a small dot or disc as it travels across the sun's face.
This event will not happen again until 2117.
On Tuesday evening, residents can watch the event proceed at the Night Sky Viewing area at Cherry Springs State Park near Coudersport in Potter County.
The sky event, called Transit of Venus, begins around 6 p.m., but Greg Snowman, environmental education specialist with the state Department of Conservation and Natural Resources, said visitors should plan to arrive at 5:30 p.m.
"This is similar to a solar eclipse by the moon but, given the distance from earth, Venus appears as a small black disk moving across the face of the sun. Currently, views of Venus are seen as a thin crescent," Snowman said.
Viewing the powerfully bright sun doesn't happen with the blind eye. Instead, special equipment - from the most simple to the most elaborate telescopes - can be used.
Snowman said visitors need not worry about bringing anything to the program. The park will provide what is needed to safely view the event.
"We have telescopes that are specifically designed to view the sun and filters that can be used on the telescopes that we use in our Night Sky programs," he said. "It is important that a person should never view the sun directly without the proper equipment, as they may risk damage to their eyes."
The actually transit of Venus will last about 6 1/2 hours, but Snowman said the program will end when the sun goes down.
Cherry Springs State Park is famous for its dark skies. It is the first and only place in Pennsylvania to be considered a Dark Sky Park, an accolade given to the area by the International Dark-Skies Association.
According to the program website, areas with this certification are defined as "a park or other public land possessing exceptional starry skies and natural nocturnal habitat where light pollution is mitigated and natural darkness is valuable as an important educational, cultural, scenic and natural resource."
Snowman describes Cherry Springs is "the place to be for astronomy."
He said the park is 15 miles from two small towns - Coudersport and Galeton.
"These towns are located in the valleys, so lights from these communities are blocked by the surrounding hills," he said.
At an elevation of 2,300 feet, the park is not surrounded by any other higher peaks that could block the view.
"The Night Sky area offers visitors an excellent 360-degree view of the night sky. The park is in the heart of the undeveloped 262,000-acre Susquehannock State Forest," Snowman said.
"We are fortunate to have a place like Cherry Springs State Park, where people can come and experience the beauty of the night sky the same way that our ancestors did thousands of years ago," he said.
In this country, fewer than one in 10 people can see the Milky Way from where they live.
"In late summer, with the Milky Way almost directly overhead, it truly is an amazing site," Snowman said.
Astronomy programs such as the Transit of Venus, are free and are conducted every Friday through Saturday evenings, starting Memorial Day through Labor Day, and every Saturday through October.
"This is truly a once in a lifetime astronomical event," Snowman said of the Transit of Venus spectacle.