North America to witness total solar eclipse Aug. 21

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On Aug. 21, a rare event few people in North America might ever witness will transform the heavens—a total solar eclipse. People within its 70-mile-wide path will witness the sun completely blocked by the moon, while those outside this path will see a partial eclipse.

If individuals travel a little west or southwest of Fort Knox—the center of the 70-mile path—they will see this event as it moves across the U.S. from Salem, Oregon, over this area on its way to Charleston, South Carolina. Not only will the sun be totally blocked, turning day to night for more than two minutes, eclipse watchers will see a rare natural spectacle—the sun’s sheer outer atmosphere, or corona.

But, Capt. Aaron Heltunen, an optometrist from Fort Hood, Texas, on assignment at Ireland Army Health Clinic in support of Cadet Summer Training, warns that there is a danger in watching an eclipse—burning the retina of the eye, which could result in blindness. Some people may recover their sight, however others suffer permanent loss of vision.

In order to avoid temporary or permanent damage to the eyes, he suggests eclipse watchers follow these precaution:

Use approved solar eclipse viewers. The only safe way to view this event is through certified solar filters, such as “eclipse glasses,” or viewers that meet international standard ISO 12312-2. To make sure an individual is actually getting “eclipse glasses,” make sure they’re marked to meet ISO 12312-2, or sometimes written as ISO 12312-2:2015. Heltunen added that ISO-certified filters not only reduce visible sunlight to safe and comfortable levels but also block solar UV and IR radiation.

He said this means that regular sunglasses, smoked glass, photographic film, unfiltered telescopes or magnifiers and polarizing filters are unsafe. Also, stay away from “space blankets,” potato-chip bags, DVDs and any other eclipse-watching homemade filters. They aren’t safe because they seem like they dim the sun, but they don’t dim the whole electromagnetic spectrum, and infrared radiation will still damage an individual’s eyes.

If an individual can’t find eclipse viewers in stores or online, build a pinhole projector to watch the eclipse. http://solar-center.stanford.edu/observe/

Never look directly at the sun without eye protection, even briefly, except during totality. Only within the two minute path of totality, and only during this time, can an individual safely view the eclipse with the naked eye. Otherwise, an individual’s eyes should always be protected by ISO-certified filters.

Be aware of harmful solar exposure. If an individual stares at the sun without protection, they may experience damage to their retina—it’s the nerve tissue at the back of the eye. Heltunen explained that the damage to the eye is called solar retinopathy, resulting in permanent vision loss. Just as a magnifying lens can be used to focus sunlight to start a fire, staring at the sun with the naked eye damages the retina. Since it doesn’t have pain receptors, damage to the retina happens without any sensation of pain. Individuals should visit their local optometrist immediately if they accidentally stare at the sun without protection.

But with the right protection, and by driving to the right part of the state, individuals can enjoy the first full solar eclipse Kentucky has seen in a long time.

“This is supposed to be the first coast-to-coast solar eclipse here in the U.S. since 1918—the last total solar eclipse happened in the continental U.S was 1979,” said Heltunen. “It’s the kind of once-in-a-lifetime event people document so they can pass on to their families.”

Heltunen added that individuals have to drive to Fort Campbell, Kentucky, area—around Hopkinsville, Kentucky—or over to the western part of Kentucky, like Paducah, Eddyville and Kuttawa to see the full eclipse. And the largest local city in the path of the total solar eclipse is Nashville, Tennessee.

“If you are someone who likes to prepare large family parties or get-together’s, place a note on your calendar for April 8, 2024—that’s the next date for a total solar eclipse in the U.S. But that one is predicted to move from southwest to the northeast.”

To find a list of certified solar filters and viewers, and when and where to view the eclipse, visit eclipse.aas.org. For more information about the eclipse, visit eclipse2017.nasa.gov and aoa.org. n