A solar eclipse happens when the moon passes between the Earth and the sun so the moon’s shadow falls on the Earth. On Aug. 21, there will be a total solar eclipse in a 70-mile wide band from Oregon to South Carolina. There will be a partial eclipse in the rest of North America. Millions of Americans will see this spectacular spectacle.
Over an hour or so, people within this band of totality will experience increasing excitement as the moon gradually covers more and more of the sun. As the sun blinks out, it will get dark and noticeably cooler. If skies are clear, people will see the sun’s corona, the super-hot, outer layer of the sun’s atmosphere.
Solar eclipses were terrifying in ancient times. To this day, a total eclipse is a spooky experience even though we understand what causes it. That total solar eclipses occur at all is due to an amazing coincidence. The moon and the sun appear to be the same size in the sky, even though the sun is 400 times larger in diameter than the moon — but the sun is 400 times as far away.
In State College, we will see a partial eclipse.
▪ At about 1:15 p.m., the moon will start to cover the sun, gradually covering more and more of the sun’s disk.
▪ At 2:38 p.m., the eclipse reaches a maximum, with 77 percent of the sun’s area covered.
▪ The moon continues its journey across the sun’s face, until, at 3:57 p.m., the eclipse ends.
There is one rule for safely observing the eclipse: Like on any other day, don’t stare at the sun with the naked eye.
There are several ways to watch the partial eclipse safely. One method is to get a 2 by 4 1/4 inch piece of No. 14 welder’s lens — only No. 14 is safe — at a welding supply store for $2 or less. Through this dark glass, you can see the small disk of the sun.
Another option would be to use binoculars to transmit the view to the ground. To do this, you can put binoculars on a tripod and focus the magnified image of the sun onto a piece of paper on the ground. Depending on your binoculars, this image might be 2 or 3 inches in diameter, making it easy to see. Do not (I repeat!) do not, look through the binoculars at the sun. You should cover one of the lenses so light comes through only one side of the binoculars. Experiment with this before eclipse day to make sure your setup works.
The Penn State Astronomy Department is planning activities for the public on Eclipse Day. Its website and Facebook page will have details closer to Aug. 21. Also, keep an eye on the Centre Daily Times for other public activities.
OLLI at Penn State — open to adults who love to learn is offering 80 courses this summer. William Arden and Robert Baillie led an OLLI course on the eclipse this past March to get OLLI members ready for the big event. To receive a free catalog for the upcoming fall semester, call OLLI at Penn State at 867-4278 or visit olli.psu.edu.
Robert Baillie, of State College, has traveled the world to see three total solar eclipses.