The solar eclipse is a celestial phenomenon that is expected to draw tens of thousands of people to locations along the path of totality -- all with their eyes trained to the sky. But anyone eager to view the event should keep in mind some safety tips.
While we avoid staring at the sun on instinct, the temptation to look may overcome the common sense that keeps our eyes averted. During the totality phase, which lasts a little more than two minutes, it’s safe to look directly at the sun. But in the time before and after totality, even looking at a small sliver of the sun peeking out from behind the moon can irreversibly damage your retinas, according to Russell N. Van Gelder, spokesman for the American Academy of Ophthalmology.
So it’s crucial that you ready yourself with the necessary equipment.
For most, this will likely be the paper eclipse glasses with solar filters that you can find for a few dollars at various local retailers. Keep in mind when purchasing your glasses, or if you’ve already gotten yours, that they’re only safe if they’re certified. Check for the code ISO-12312-2 somewhere on the back.
There are also several other ways to safely view an eclipse without the certified paper glasses, as well as some alternatives that, while they might seem like a good idea, still pose just as much risk to your vision.
Remember these tips to safely view the eclipse:
- A pinhole projector, which can be made from material you likely have around your house, will allow you to view the reflection of the eclipse as it happens. Simply cut a square out of the middle of a piece of cardboard, tape a sheet of aluminum foil over the opening and then poke a pinhole in the foil. Hold the cardboard up to the sun, and let the sunlight fall through the hole onto another piece of cardboard.
- A cereal box can be used in almost the same way. Find instructions on how to make a cereal box pinhole viewer here: https://eclipse2017.nasa.gov/sites/default/files/EclipseCerealBoxViewer.pdf
- You can also hold a colander toward the sun during the partial eclipse and see many tiny images of the eclipsed sun reflected on the ground or a wall.
- A welding helmet will protect your eyes from the harsh ultraviolet and infrared waves.
- Looking at the eclipse through a telescope or binoculars is even more dangerous than looking at it directly, because they concentrate the rays. Telescopes are safe for viewing an eclipse only with a special certified lens.
- If you don't want to buy a certified lens, learn how to eclipse-proof your binoculars here: http://bit.ly/2tiJ2Ay