A safe pair of solar eclipse glasses should be labeled with ISO 12312-2 (sometimes written in more detail as ISO 12312-2:2015), which is an international safety standard. But isn't it possible for fakes to just print that number? Of course! So here's a list of manufacturers that are acknowledged to be safe. * indicates they are from outside of U.S.
Solar Viewer Brands
- American Paper Optics (Eclipser) / EclipseGlasses.com / 3dglassesonline.com
- APM Telescopes (Sunfilter Glasses)*
- Baader Planetarium (AstroSolar Silver/Gold Film)*
- Celestron (EclipSmart Glasses & Viewers)
- DayStar (Solar Glasses)
- Explore Scientific (Solar Eclipse Sun Catcher Glasses)
- Halo Solar Eclipse Spectacles
- Jaxy Optical Instrument Co., Ltd.*
- Lunt Solar Systems (SUNsafe SUNglasses) [see their unique kid-size eclipse glasses]
- Meade Instruments (EclipseView Glasses & Viewers)
- Rainbow Symphony (Eclipse Shades)
- Seymour Solar (Helios Glasses)
- Solar Eclipse International / Cangnan County Qiwei Craft Co.*
- Thousand Oaks Optical (Silver-Black Polymer & SolarLite)
- TSE 17 / 110th.de (Solar Filter Foil)*
Now if your glasses have the ISO number but wasn't from one of those manufacturers they may still be good. But you'll want to test them. First thing to know, don't test them by staring at the sun.
The American Astronomical Society suggests you check sunlight reflected off a mirror or a shiny metal object. If sun is behind the clouds or on the other side of the earth when you want to test your glasses, you can use a bright-white LED such as the flashlight on your phone or a bare lightbulb. The reflected sunlight or bright, white, artificial light should appear very dim through a safe pair of eclipse glasses. If you can see light behind a lamp shade or a soft, frosted light bulb through the glasses through your eclipse glasses, then they aren't strong enough to stare safely at the sun.
When staring at the sun through safe solar eclipse glasses, the sun should appear comfortably bright like the full moon, according to the American Astronomical Society .