NASA recommends only using eclipse glasses with ISO 12312-2 printed on them that have been manufactured by four U.S. companies: American Paper Optics, Rainbow Symphony, Thousand Oaks Optical, and TSE 17.
NASA officials say buying your eclipse glasses on Amazon does not ensure their safety. They say you should check your eclipse glasses and viewers to verify that they have the correct ISO designation and were manufactured by one of the four companies recognized by NASA as legitimate.
NASA also recommends that residents not reuse old eclipse viewing glasses, as they become unsafe after three years. Also, lenses that are scratched or wrinkled are not safe to view the event.
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NASA safety info for eclipse
