Let’s start here: Do not look directly at the sun without adequate eye protection. Not ever. Not even during a solar eclipse, when the moon seems to be blocking the sun. Looking directly at the sun can, at best, cause something similar to a severe sunburn on your retinas. At worst, it can leave you permanently blind.
On August 21, 2017, a total eclipse of the sun will be visible across the United States in a viewing path that reaches from the Atlantic to the Pacific. The last time a total solar eclipse could be viewed from the continental United States was in 1979 and the next one won’t happen until 2023. What’s a curious person supposed to do?
Get your hands on solar eclipse glasses. Good ones – certified to meet ISO 12312-2 standards. But, wait. There’s a catch. Even if a pair of glasses carries the ISO certification label, you can’t be sure they’re safe. Unfortunately, unscrupulous manufacturers are printing that label on fake eclipse glasses.
Do not trust your eyesight to solar glasses if you’re not positive they meet the recommended safety standards.
To help consumers, the American Astronomical Society offers a list of recommended manufacturers and retailers found here. If you don’t have time to purchase glasses from a trusted source, you still have several options:
- Check your local library or science museum. Many are giving away free eclipse glasses, and you can be almost positive they are certified correctly.
- If you already have glasses, put them to this simple test: Hold them in front of a very bright light, such as a bright halogen bulb or the light from your phone’s flashlight. According to the AAS, "All such sources should appear quite dim through a solar viewer. If you can see lights of more ordinary brightness through your eclipse glasses or handheld viewer, and you're not sure the product came from a reputable vendor, it’s no good."
- Make yourself a simple pinhole viewer such as one of the two types described here.
And don't forget sunscreen for your face and all other exposed skin.