It's time to get your order in for solar eclipse glasses.
In 2017 — the last time a total eclipse was visible in the U.S. — eclipse glasses maker American Paper Optics of Bartlett, Tenn., was getting up to 3,000 orders a day and had to limit buyers to 50 glasses per order.
With what NASA terms an "eclipse doubleheader" coming to the U.S. — an annular solar eclipse on Oct. 14, 2023, and a total eclipse on April 8, 2024 — expect the demand to be even higher this time. (In an annular eclipse, the moon doesn't quite cover the sun, resulting in a "ring of fire" or partial covering, depending on where you're at when you view it.)
The annular eclipse this year will be most visible along a band stretching from the Gulf Coast of Texas to Oregon. The total eclipse will be visible from the Pacific Coast of central Mexico through the Midwest and a highly populated path including Dallas; Indianapolis; Cleveland; Buffalo, N.Y.; Toronto; and Montreal before passing over Maine and Canada's Maritime Provinces.
And yes, that means a small area in Texas near San Antonio will be in a prime site for both eclipses.
American Paper Optics can create custom messages on eclipse glasses to promote companies or organizations. The film in the glasses tends to be a closely guarded secret, but Ralph Chou, an expert in eye protection, told former PN correspondent Mike Lauzon in 2017 that they typically consist of carbon black within the film that is metallized with a thin aluminum layer.