If you watched the “Great North American Eclipse” on April 8, 2024, you may already have a pair of solar eclipse glasses tucked away in a drawer. The good news is that you can probably use them again. On Wednesday, Aug. 12, a partial solar eclipse will be visible across much of Europe, all of Canada and parts of the northeastern U.S. , while a total solar eclipse will sweep across Greenland, Iceland and Spain . Whether you’re reusing old eclipse glasses or buying a new pair, here’s how to make sure they’re safe — and where to find certified viewers before supplies run short.

Where And When Is The Solar Eclipse?

Millions of people across Europe and North America will need certified solar eclipse glasses to watch the partial phases of the Aug. 12 eclipse safely. Even inside the path of totality, eclipse glasses are required before and after totality, and throughout the entire event for everyone outside the narrow path where the sun is never completely covered.

The deepest partial eclipse in North America will occur in eastern Canada, where St. John’s, Newfoundland and Labrador will see 53% of the sun obscured. Halifax will see 31%, Québec City 24%, Boston 16% and New York City about 10%. Across Europe, much larger eclipses will be visible, with the U.K. seeing more than 90% coverage and many countries experiencing spectacular deep partial eclipses.

The only solar viewers that should ever be used are those that comply with the ISO 12312-2 international safety standard for direct solar viewing. Don’t look for “NASA-approved” eclipse glasses — they do not exist. Instead, use the American Astronomical Society Solar Eclipse Task Force’s list of vendors for safe solar viewers , particularly when buying online.

Can You Reuse Eclipse Glasses From 2024?

Solar eclipse glasses don’t expire simply because they’ve been sitting in a drawer for two years. If they were bought from a reputable manufacturer for the April 8, 2024 total solar eclipse — or the 2023 annular eclipse — they’re generally safe to use again, provided they’re still in good condition.

However, don’t assume that because they were safe once, they’ll still be safe today. “If you’ve got some left over from 2024, take them out, point them at a bright light bulb, and make sure there is no light coming through any pin pricks or scratches,” said Dr. Tyler Nordgren, an eclipse chaser, astronomer and space artist at Space Art Travel Bureau , in an interview. “The eclipse glasses will last several years, provided you’ve taken very good care of them.”

Before using old solar eclipse glasses:

  • Check for scratches, punctures, creases or tears.
  • Shine a flashlight through the lenses from behind to check for pinholes.
  • Ensure the cardboard frames are still secure and the filters haven’t become detached.

Where To Buy Solar Eclipse Glasses

Demand is expected to increase rapidly during the final two weeks before the eclipse, particularly across Europe where relatively few retailers normally stock eclipse viewers. However, astronomy retailers, science museums, observatories and planetariums often do stock certified eclipse glasses. Prices generally range from $2 to $5 (£2–£4) per pair, although multipacks are usually much cheaper per viewer.

Major manufacturers include American Paper Optics , Thousand Oaks Optical , Rainbow Symphony and DayStar Filters in the U.S. and Absolute Eclipse and Baader Planetarium in Europe.

Europe Could Face Eclipse Glasses Shortages

Unlike North America, which had years to prepare for the hugely anticipated April 2024 eclipse, Europe has little experience with large-scale public demand for eclipse glasses.

Although totality is limited to Greenland, Iceland and northern Spain, a very deep partial eclipse will be visible across much of Europe, including more than 90% coverage across much of the U.K.

"After equipping hundreds of millions of viewers across the United States during the 2017 and 2024 eclipses, we’ve learned that when high demand meets a last-minute rush, unsafe knockoffs flood the market,” said Jason Lewin, chief marketing officer at American Paper Optics, via email. “Europe is currently heading toward that same scenario for the August 12th eclipse. The biggest danger during a sellout isn't just missing the event—it's people turning to unverified, potentially harmful counterfeits out of desperation. Getting ISO certified, high-quality eclipse glasses early is the single most critical step anyone can take.”

More than 75 million eclipse glasses were sold for the April 8, 2024 eclipse in North America, with most purchased during the final month before the event.

Wishing you clear skies and wide eyes.