So what can be used to view solar eclipses? One widely available filter that is safe for solar eclipse viewing is a shade number 14 welder’s glass (also available in plastic), which can be obtained from welding supply outlets. Welder’s glass/filters provide excellent quality for visual observation, and shade #14 is perfectly safe. Shade #12 is also safe, but many people find the Sun uncomfortably bright when using this filter. Shade #13 is a good compromise but is not as widely available as shades #12 and #14. Do not use any lower shade number of welder’s filter, and don’t combine two shades of welder’s glass with lower numbers. In addition to welding supply stores, shade #14 welder’s filters, conveniently mounted in sturdy corrugated holders, are available from Rainbow Symphony.
During the Great American Eclipse of 2017, many people used eclipse ‘glasses’ to watch the Moon slide across the Sun’s face. Most of these eclipse ‘glasses’ are stiff paper frames with safe solar-filter material in place of lenses. The frames have arms that fit over your ears, and they sit on the bridge of your nose close to your eyes. If you need regular glasses for distance viewing, you can adjust the paper frames to fit over the front of your glasses. Because they are lightweight, and because the solar-filter material can be scratched, these eclipse ‘glasses’ need to be handled with care. Always inspect the filter material before use; if it’s scratched, punctured, torn, or otherwise damaged, discard the eclipse ’glasses.’ Read and follow any instructions printed on, or packaged with, the eclipse ‘glasses.’ The American Astronomical Society has a webpage devoted to safely watching a solar eclipse, with a link to reputable vendors of solar filters & viewers. There, the links under ‘Solar Viewer Brands’ will go to companies that sell eclipse glasses, whether or not a solar eclipse is imminent.
One final caution. Welder’s filters and eclipse shades/glasses are never to be used with optical equipment of any kind. They are for viewing solar eclipses with only your eyes, and must never be used in combination with cameras, binoculars, or telescopes. Optical gear magnifies the Sun’s light, and neither welder’s filters nor eclipse glasses are designed to withstand the intensity of magnified sunlight. Glass solar filters will shatter, the material in eclipse viewers will melt, and your eyes will likely suffer damage.