The most important aspect of any solar eclipse is eye safety. While it’s perfectly safe to view a solar eclipse if you follow safe solar viewing procedures, you can cause permanent eye damage or even blindness if you attempt to view an eclipse incorrectly. Regular or polarized sunglasses are NOT safe.
Solar Eclipse Viewing Glasses that are ISO certified are the easiest option to safely view a Solar Eclipse. The small amount of light emitted during even a 99 percent solar eclipse is still dangerous. The only time it’s safe to look at a total eclipse without proper eye protection is during the brief period of “totality” when the Sun is 100 percent blocked by the Moon.
Here’s a great safety video from the American Astronomical Society:
Unless a product has been specifically designed for safe solar viewing and has been certified as meeting international standards for such products, it’s best to assume that a device, method, or instrument is unsafe. Don’t risk it! Unfortunately, the media doesn’t always get it right and there is a great deal of misinformation in print and online about what’s safe and what isn’t. Items such as regular sunglasses, smoked glass, exposed film, medical x-rays, homemade filters, and many others are all unsafe. You can use welder’s glass to view an eclipse, but it must be #14 welder’s glass; any rating below #14 is not safe. It’s also safe to view an eclipse using indirect methods, such as projecting an image of the eclipsed Sun onto a white screen.
Note that attempting to view the Sun using cameras, binoculars, telescopes, or other optical devices without proper filters is extremely hazardous and can permanently damage the eyes in an instant. These devices need specially designed solar filters that fit snugly on the front end (the Sun side) of the device. Never attempt to view the Sun through an optical device using eclipse glasses or any type of filter that attaches to the viewing side (as opposed to the Sun side) of the instrument; the focused light will destroy the filter and enter and damage your eyes. Since viewing or photographing a solar eclipse with an optical device requires specialized equipment and knowledge, we recommend consulting with a qualified astronomer or just enjoying the eclipse with your own eyes (using safe solar viewing procedures, of course).