NASA's Solar Dynamics Observatory satellite partial solar eclipse.

How to test for fake solar eclipse glasses!

Fake solar eclipse glasses are being sold; don’t be a victim. You will cause permanent eye damage if you look at the sun with fake solar eclipse glasses. You need proper eye protection so you don’t hurt your eyes during the solar eclipse.

This information is for everyone in the United States, Mexico, or Canada.

It is not just for people in the path of the total solar eclipse. In my last solar eclipse article I mentioned that everyone in the entire country, with the one exception of mainland Alaska, will have the opportunity to see a partial eclipse.

We are currently in Texas heading to a campground located in the path of the total solar eclipse and we already have our solar eclipse glasses.

Viewing the total eclipse, from our campsite at Cascade Lake in Idaho. Take notice of our solar eclipse glasses.
Viewing the total eclipse, from our campsite at Cascade Lake in Idaho. Take notice of our solar eclipse glasses.

Eye damage can occur nearly anywhere the partial eclipse can be seen. Canada, Mexico, and the United States. All three will have a partial eclipse and the shadow path of the total solar eclipse will also cross all three countries.

Partial eclipse

A partial solar eclipse is when only part of the sun is obscured by the moon. Even if you are in the shadow path of the total solar eclipse, you will also have a partial solar eclipse both before and after the total solar eclipse.

Old Farmer's Almanac solar eclipse
Old Farmer’s Almanac photo of the partial and total solar eclipse

Do not look at the sun

Do not look at the sun unless it is totally obscured (not just during a solar eclipse), without solar eclipse glasses. The only time it is safe to look at the sun is when it is 100% obscured by the moon during a total solar eclipse. Everyone attempting to observe the total solar eclipse needs solar eclipse glasses. When the sun is only 99.9% obscured it is still dangerous to your eyes.

Solar eclipse glasses

Solar eclipse glasses block out 1000 times more light than sunglasses. Sunglasses will not protect your eyes if you look at the sun. If you don’t protect your eyes, you will hurt your eyes. Solar retinopathy is the damage to the retinas if you look at a partial eclipse without proper protection. Solar retinopathy is painful and can change your vision (including blindness), for the rest of your life. It only takes a very short exposure to the sun; even if it is mostly obscured to damage your eyes.

I described pretty much everything you need to know about the solar eclipse in my last post, but I only mentioned protecting yourself from eye damage. This week I am going to cover this critical information about solar eclipse glasses and it applies to everyone. Here is the link to last week’s article. Going to the 2024 total solar eclipse

ISO 12312-2 standards

ISO 12312-2 describes what you need to do to create solar eclipse glasses. Companies selling solar eclipse glasses nearly always have this printed on the paper part of solar eclipse glasses. The problem is that some of the glasses being sold as safe are not safe and will not protect your eyes. Yet they still print the ISO 12312 on the glasses.

Solar Eclipse Glasses with ISO certification.
Solar Eclipse Glasses with ISO certification. Also in the picture are normal sunglasses and you can see through the lens. With solar eclipse glasses, you can’t see anything except when you look at the sun.

Buy your solar eclipse glasses from one of the manufacturers on the American Astronomical Society list. Here is a link to the list. Suppliers of Safe Solar Viewers & Filters

How to tell if your solar eclipse glasses are safe without damaging your eyes.

Test one: Test with a bright light and your cell phone instead of your eyes. Get a very bright light bulb, put your cell phone in video mode, and put the glasses in front of your cell phone camera lens. Looking at the monitor of your phone, you should not be able to see anything except perhaps the most faint outline of the light source.

The American Astronomical Society lists these possible test light sources. “the hot filament of an incandescent light bulb, a bright halogen light bulb, a bright-white LED bulb (including the flashlight on your smartphone), a bare compact fluorescent (CFL) bulb”

Test two: Assuming that your eclipse glasses pass test number one then put on the glasses and look at your test light source. You should not be able to see anything. Sunlight is far brighter than any light source on the list.

Look at the sun, or a reflection of the sun, with your solar eclipse glasses only if they first pass the previous tests. Don’t risk your eyesight with fake solar eclipse glasses.

“You shouldn’t be able to see anything through a safe solar filter (solar eclipse glasses) except the Sun itself” Quote: American Astronomical Society

Eye safe does not mean telescope or binocular safe

Solar eclipse glasses are not intended for use with magnifying devices. Do not expect solar eclipse glasses to protect your eyesight if you hold them in front of, or behind a magnifying device. If you are not sure of the safety of viewing the eclipse through a telescope, then don’t do it. Astronomers use much darker filters than solar eclipse glasses when viewing the sun with a telescope.

Solar eclipse glasses are not for cameras

Solar eclipse glasses or viewers are not dark enough for camera electronics. If you take a photo with your cell phone of a partial solar eclipse without a proper filter, you may damage your camera. If you take a photo of the partial solar eclipse using only your solar eclipse glasses as a filter, you may damage your camera. Cameras are more sensitive to light than your eyes. That is why we used the camera when conducting the above tests using light bulbs as the light source.

During the few minutes that the sun is obscured by the moon, it is safe to use your camera without solar eclipse glasses.

Tips for using your camera during a total solar eclipse

Telephoto shots of the sun, during a total solar eclipse can be wonderful. You will be photographing the corona around the sun. If you can control your camera settings I suggest ISO 400, f-stop f5.6 or higher with shutter speeds between one-half a second up to and including 1/2000 a second. With a telephoto length of 200mm. Set your focus on infinity. Speeds lower than 1/4 a second will tend to blur your photos because the sun and moon will move during your picture. During the total solar eclipse expect the telephoto pictures to look like black and white photos.

Forbes Magazine total solar eclipse corona Chile 2019
Forbes Magazine, Total Solar Eclipse Corona, Chile 2019

Don’t forget to also take wide-angle shots of the surrounding area during a total solar eclipse. Twilight, like just after sunset, will be in every direction. These wide-angle shots can be amazing. If you have a very wide-angle lens and place your camera in portrait mode then you can have both the obscured sun and the horizon in the picture. This shot will be difficult because the sun will be so high in the sky.

Total Eclipse, Campsite, Cascade Lake, Cascade Idaho
The lake next to our campsite during the total solar eclipse in 2017 at Cascade Lake in Idaho

If your camera has a night setting try that too both in telephoto shots and wide-angle shots.

Don’t forget to enjoy the eclipse

Be prepared for the colder temperatures, expect the temperature to drop by about 20 degrees. You may want to have a small flashlight because it is going to get dark. A red lens cover on your flashlight is ideal because it doesn’t change your night vision.

When the sun is obscured by the moon, then you can take off your solar eclipse glasses until you start seeing the sun peak back out from behind the moon. Quickly after that, it will be bright daylight. I so hope for a clear day on April 8th.

Don’t take so many photos that you fail to enjoy the moment. Being in a total solar eclipse is very rare and worth the experience.

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Solar retinopathy

Suppliers of Safe Solar Viewers & Filters

NASA 2024 Total Solar Eclipse

Great American Eclipse


NOAA’s GOES Satellites

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7 thoughts on “How to test for fake solar eclipse glasses!”

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