WEST CHESTER >> The odds are good that on Aug. 21 most Americans are going to duck out of their workplaces and look up at the sky. That’s the date the moon will pass in front of the sun and create a total eclipse, which is being called “The Great American Eclipse.”
It will be the first total solar eclipse visible to the entire continental United States since 1979, although the path of complete totality is a relatively narrow path from the Northwest to the nation’s Southeast.
In Chester County, the sun will be about 80 percent obscured, looking like a big white cookie with a four-fifths bite taken at its maximum at 2:44 p.m.. It visibility of the eclipse itself will begin in southeastern Pennsylvania about 1:30 p.m. and wind up about 4 p.m.
Chester County Astronomical Society President Roger Taylor is so excited about the event that he is planning to drive to the area of the Smoky Mountains to see 100 percent coverage. If it happens to be cloudy or otherwise bad weather, he said he will drive to any other place where the skies are clear and the view is good, no matter how far.
“The nation’s highway system is very good. We can go to a better place in a short time if the weather is bad,” he said.
For most Americans who habitually look up, an eclipse is something they have probably viewed, especially a lunar eclipse. But this one is special, because what is usually seen is partial and it is the moon rather than the sun.
Taylor, 67, said he has been in love with astronomy for 40 years, ever since he set out to make his own reflecting telescope. Ever since then, his eyes have been on the sky and his hands wrapped around telescopes. Even this week, as the annual Pleiades meteor show appears in the sky with the glowing remnants of Swift-Tuttle comet’s tail shooting through the earth’s atmosphere, he is thrilled to see them return every August
One of his incentives for driving south to see the solar eclipse totality is to see the sun’s corona — its outer atmosphere that has its own luminosity but is lost to visibility in the glow of the sun’s usual brightness. If Taylor is really lucky, he will also see for several seconds the “diamond ring,” that is the sun disappearing or reappearing as a glowing spot between the mountains of the moon.
Taylor said that on the surface, it would be reasonable to think that every time the moon circles in front of the sun there would be an eclipse, but that does not happen.
“Why don’t we have an eclipse every month? Because the moon’s orbit it tilted and we only get about six or seven totals in a century,” he said. The next one is scheduled for April 8, 2024 and then not another one until Aug. 12, 2045.
What will it be like?
Taylor said in this area it will be like dusk. Unlike the ancient legends when a solar eclipse occurred unexpectedly, when there were stores of the elephants rushing to the mountains, dragons consuming the sun and fears of the ends of the earth, the conditions in Chester County will be like a cloudy day.
“Maybe the nocturnal insects will start to sing for awhile,” he said.
Taylor said most people will be eager to watch the whole thing, but he issued warnings: “Never look at the sun ... only at the totality.”
There are several ways to watch, however. One, he said, is to make a pin-hole viewing device:
Take a box, about the size of one from the liquor store, that you can cut out the bottom and place over your head. In a back corner behind your head, cut out a small square and cover it with aluminum foil. Poke a small hole in it. On the side in front of your face inside, paste white paper. To view, let the image of the sun come in from behind you and land on the paper in front. (See instructions online for a pin hole camera).
Another way is to get solar filter glasses. These are being distributed by the Franklin Institute and other places. They are especially dense filters. Don’t use regular sunglasses.
For those who want to photograph, set up a tripod and get a solar filter to place over the lens. These can be obtained (cardboard) for less than $30, or they can be very expensive out of metal and glass.
Taylor added that looking through a telescope or binoculars can concentrate the light and burn eyes even worse than staring bare-eyed.
“You can go blind ... Permanent, It will damage the vitreous humor or burn the retina,” he said.
So good luck and hope for a clear day.
The Chester County Astronomical Society meets the second Tuesday of the month September through May at 7 p.m. at the Merion Science Center at West Chester University, 750 S. Church St., Room 113, West Chester. Check their Web page at www.ccas.us.