NASA says your eclipse glasses may be unsafe. Here’s how to tell if they’re not

August’s upcoming eclipse will be eagerly taken in by millions of people across the nation, and except for a scant few minutes if you are in the path of totality, almost all of it will be watched through eclipse glasses. Now NASA is warning that some of those glasses may not be safe.

“There are unsafe paper solar glasses being distributed,” said NASA in a release Friday.

Glasses that are safe to use for eclipse viewing will be certified by ISO with a reference number of 12312-2 printed on the glasses.

NASA lists American Paper Optics, Rainbow Symphony, Thousand Oaks Optical and TSE 17 as reputable producers of eclipse glasses whose products can be trusted. They also recommend AstroSolar Silver/Gold lensed glasses by Baader Planetarium.

Eclipse glasses can be quite fragile, and NASA advises that there are instances in which, even if manufactured properly, they may be unsafe. If lenses are scratched or wrinkled they should not be used, and glasses older than three years are similarly dangerous.

The use of homemade filters is also discouraged by NASA, as even exceptionally dark ones provide no protection while looking at the sun.

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