How to tell if your eclipse glasses will actually protect your eyes

HUNTSVILLE, Ala. - The solar eclipse in the U.S. August 21 promises to bring millions of Americans into the path of “totality.” A NASA scientist is warning area residents to take care to protect their eyes -- correctly.

While the near-total eclipse you would see in north Alabama will provide a unique viewing experience, basically you cannot look at the sun directly or you will face a serious eye injury. The basic problem is that because the sun’s rays will be dimmed, people might assume it’s safe to gaze at it, but that’s not the case.

“So, as the eclipse, especially those people close to the path of totality but not in it, they’re going to look up and they’re thinking, ‘Well, this ain’t so bad,’” said Bill Cooke, a Marshall Space Flight Center-based NASA astronomer and meteor scientist. “And it is bad, they just don’t realize they’re damaging their eyes.”

If you want to look at the eclipse, listen to a NASA expert. Cooke says residents needs to wear certified glasses during the eclipse, which is set to begin right around noon in Nashville, with the total eclipse visible there from 1:27 p.m. to 1:29 p.m.

Nashville is the largest city in the path of the eclipse. The eclipse will be visible in Oregon and make its way across the country to Charleston, S.C.

“Now here in Huntsville, it won’t be total,” Cooke said. “If you want to see totality you have to go up, north of Nashville or somewhere north in Tennessee. Here in Huntsville 97 percent of the sun will be blocked.”

But even then, it could be dangerous. So how do you tell if the glasses you have are certified and will provide adequate safety?

That can be tricky. Fortunately, help is available, Cooke says.

“And we’ve had some problems that people are generating glasses and they stamp this ISO thing on it, but they’re really not rated for it,” he said. “So, the American Astronomical Society has a website you can go to that lists manufacturers that do manufacturer glasses like this that do meet the standard.”

The issue centers on the ISO safety rating. The required number for glasses that provide proper protection to view the eclipse is ISO 12312-2.

But, Cooke says people need to do a little more checking.

On its website the American Astronomical Society advises, “Even more unfortunately, unscrupulous vendors can grab the ISO logo off the internet and put it on their products and packaging even if their eclipse glasses or viewers haven't been properly tested.

“This means that just seeing the ISO logo or a label claiming ISO 12312-2 certification isn't good enough. You need to know that the product comes from a reputable manufacturer or one of their authorized dealers.”

The Society’s website also provides a list of reputable manufacturers and authorized dealers.