Can you make DIY solar eclipse glasses?

A total solar eclipse will fly across North America on April 8 — and it won’t happen again for another 20 years, says NASA.

You may not want to miss it, but staring at the sun for even just a few seconds can blind you or cause lasting eye damage.

The only time one can safely stare at the eclipse is when it’s completely covered by the moon. Although, even if most of the sun is covered by the moon and there is just a bit of light peeking through, it’s more than enough of the sun to damage your vision.

And be warned, unless it has a solar filter, looking at the eclipse through a camera lens or binoculars won’t keep you any safer than looking with your own eyes.

“Viewing any part of the bright sun through a camera lens, binoculars, or a telescope without a special-purpose solar filter secured over the front of the optics will instantly cause severe eye injury,” NASA said on its website.

Luckily, there’s a way to view the eclipse safely, with a pair of special eclipse glasses, though NASA said they don’t approve of any particular brand of solar viewer.  They warned people that normal sunglasses are not safe for eclipse viewing “no matter how dark” they are.

“Safe solar viewers are thousands of times darker and ought to comply with the ISO 12312-2 international standard,” NASA said.

They urged people to check their eclipse glasses or handheld viewers for tears scratches, or any signs of damage. The American Astronomical Society published a press release warning people to be on the lookout for counterfeit glasses and provided a list of brands that meet the safety requirements.

NASA didn’t say anywhere on their website that people should attempt to make their own solar glasses.

Instead, if people can’t get their hands on eclipse specs, NASA said they can use an “indirect viewing method, which does not involve looking directly at the sun.” They recommended people make a pinhole projector, which has a small opening that projects an image of the sun onto a nearby surface.

“Do NOT look at the sun through the pinhole!” NASA warned.

NASA said people can build their own pinhole projector with common household items.

Live Science shared a step-by-step how-to guide on how to create a homemade eclipse viewer.

Your materials

Grab yourself a cardboard box, like a shoebox, for example, a white sheet of paper, tape, a pin, aluminum foil and a box cutter.

Cut a hole

Use the box cutter to make a one-inch hole on one side of the shoe box, close to the top.

Grab your foil

Take some tinfoil and tape it over the hole you made in the cardboard box.

Punch a hole

Grab the pin and punch a hole through the center of the foil.

Make a paper screen

Tape some white paper inside the box on the side directly across from the hole. This is your DIY projection screen where you’ll be able to see the sun shining through the hole

Create your viewing hole

You never want to look at the sun through the pinhole, as this can damage your eyes. Instead, you’ll cut a hole on the side next to the white piece of paper so that you can view the eclipse on your homemade screen.

Watch

You can test your homemade viewer by taking it outside during the day. With your back to the sun, make sure the viewer is lined up with its own shadow.

Now look through the hole you cut on the side of the box and look for a circle of light on the white paper.

During the eclipse, you’ll see a shadow pass over the point of light.