On Aug. 21, one of Mother Nature’s most glorious spectacles will grace the skies of the mainland United States: a total solar eclipse.
The moon will completely block the sun in a roughly 70-mile-wide corridor that runs east-southeast from Oregon’s Pacific coast, cutting right through Wyoming, Nebraska and Missouri, and all the way across the continent to South Carolina.
People inside this narrow path will be dazzled by the unforgettable spectacle of a pitch-black hole in the sky—where the sun is supposed to be—surrounded by the diaphanous whitish glow of the solar atmosphere (the corona). There’s no other sight like this in the world.
Having seen five total solar eclipses myself, I cannot stress enough that it’s absolutely worth your time and effort to do whatever you can to get inside the path of totality at the time of what’s being called the Great American Eclipse. To paraphrase Mark Twain, the difference between a total solar eclipse and a 99.99-percent partial solar eclipse is like the difference between a lightning bolt and a lightning bug.
But if you remain in the Harrisburg area, you can still enjoy watching a partial solar eclipse unfold over the course of 2 hours and 42 minutes. But make sure you take the proper precautions to view the eclipse safely.
The time of when the eclipse begins and ends depends on your exact location. But if you’re in or near Harrisburg, the moon will begin to move across the sun’s disk at 1:17 p.m. The maximum blockage of the sun will occur at 2:41 p.m., when the moon will cover 77 percent of the sun’s disk. And the eclipse will end at 3:59 p.m.
Although 77 percent sounds like a lot of sun blockage, you probably won’t notice any darkening of the sky, though you might notice slightly cooling temperatures.
Looking directly at the sun for just a few seconds, even when the partial eclipse is at maximum, can cause permanent damage to your eyesight if you don’t use the proper protection. And whatever you do, do not look at the sun directly for even a brief moment through a telescope or binoculars unless a special filter is mounted on the front end of the instrument.
Fortunately, there are inexpensive methods for observing the partial eclipse safely.
You can order eclipse glasses online, and many public libraries are giving them away for free. These glasses block out almost all of the sun’s light, so you can stare safely at the sun for hours. But do not use eclipse glasses with a telescope or binoculars; they are for your naked eyes only.
Another way to view the partial eclipse is to project the image of the sun by punching a small hole in a sheet of paper and letting the eclipsed sun’s light pass through the hole onto another sheet of paper. Alternatively, if you stand near a tree, its leaves will act as natural pinhole cameras, projecting dozens or hundreds of images of the partially eclipsed sun on the ground or pavement.
If you plan to use a telescope or binoculars, make sure to securely install a special solar filter on the front end of the viewing instrument. The least expensive option is Baader AstroSolar Safety Film, which has the texture of aluminum foil. You can tape the film over the front of the telescope or over both lenses of binoculars.
If you travel into the path of totality, it’s perfectly safe to remove the filter and view the eclipse with your naked eyes or with binoculars once the sun is completely blocked at totality. In fact, if you use a filter during totality, you’ll see nothing at all. If you’re near the center of the narrow path, totality will last two to two-and-two-thirds minutes, depending on your location.
Obviously, there won’t be anything to see if your sky is cloudy at eclipse time. In general, the western United States has the best weather prospects. But no matter where you go, I recommend checking the weather forecast the night before the eclipse and be prepared to drive to an alternate location with better prospects for clear skies at eclipse time. With tens of millions of eclipse chasers from all over the world expected to be in the path of totality, expect heavy traffic.
If you’re interested in photographing the eclipse, my advice is to use the time between now and the eclipse to practice photographing the sun at the local time of the eclipse. Numerous websites, such as MrEclipse.com and Eclipse-Chasers.com, offer practical tips. But if you’re in the path of totality, spend almost all of your time actually looking at the eclipse. Don’t waste this precious time fiddling with camera equipment.
The Aug. 21 eclipse will be the first to touch the U.S. mainland since 1979. And it’s the first coast-to-coast eclipse since 1918. The path of totality crosses 14 states (although just tiny portions of Montana and Iowa) and five state capitals. And amazingly, it’s the first solar eclipse in which totality can be seen exclusively from the United States since our Founding Fathers declared independence in 1776.
A typical location on Earth gets one total solar eclipse every 375 years on average. The last total eclipse to pass over Harrisburg was in 1478—before Columbus’s first voyage to America. The next won’t take place until 2144—when nobody reading this article will still be alive.
If you miss the Aug. 21 eclipse, you’ll have another shot on April 8, 2024. A total solar eclipse will cross the United States from Texas to Maine, and the narrow path of totality will pass over the very northwestern part of Pennsylvania, in and around Erie.
The State Museum of Pennsylvania’s planetarium will run shows about the eclipse from Aug. 9 to 20.
Raised in Hershey, Robert Naeye was editor-in-chief of Sky & Telescope magazine from 2008 to 2014.