The mainland United States has not experienced such a celestial event since 1979. The rarity of these events means many of us may not be aware of the potential dangers. Fortunately, NASA and other experts are here to help.
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Watching an eclipse can be a mesmerizing, unforgettable event, but it can also cause permanent eye damage without the proper safety precautions. With the countdown just past the one-month point, NASA has published a set of safety tips for those who are planning to watch, so that viewers have the right safeguards in place before they become transfixed by the incredible sight.
“NASA isn’t trying to be the eclipse safety glasses ‘police,’” Alex Young, associate director for science in the Heliophysics Science Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. But “it’s important that individuals take the responsibility to check they have the proper solar eclipse viewing glasses.”
The only safe way to look directly at the sun is with special solar filters. Those can come in the form of glasses or handheld solar viewers. NASA’s guidelines advise viewers to use only glasses or viewers with certification information with a designated ISO 12312-2 international standard. They should also have a manufacturer’s name and address printed on them.
People also should ensure that their glasses or viewers are not older than three years and don’t have scratched or wrinkled lenses. NASA warns against using any homemade filters and ordinary sunglasses, even if the lenses seem very dark.
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Alan MacRobert, senior editor at Sky & Telescope magazine, says that staring at the sun is akin to using a magnifying glass to set paper on fire. “Your eye lens is magnifying glass, and your retina is the piece of paper.”
Watching an eclipse without the appropriate protection can cause solar retinopathy, which the American Academy of Ophthalmologists describes as an injury to retinal tissues commonly associated with sun gazing or eclipse viewing that can result in impaired vision. Recovery is unpredictable and uncertain. Sometimes, the damage can be permanent.