Skies from the South Pacific to northwestern Pennsylvania will darken due to a total solar eclipse on April 8, 2024.
With just under five months to go, eclipse-watching fans have plenty of time to prepare for the event by acquiring a pair of eclipse glasses.
The purpose of eclipse glasses is pretty simple; they only let through a small fraction of light — enough to see the moon cover the sun, but not enough to do any damage.
The glasses are certified by the International Standardization Organization, which sets guidelines for everything from camera speeds to anti-bribery measures.
“It’s not against the law to have glasses that would not meet this standardization — ISO 12312-2 — but it would be inadvisable not to use that kind of solar filter because it would be dangerous to your eye,” said Associate Professor of Physics Jamie Lombardi. “The basic idea is to protect you from the light so you that you don’t have retinal damage.”
Lombardi added that ultraviolet light from the sun can cause cataracts, a medical condition where one’s eyes and vision blur and become cloudy.
The solar film on the glasses only allows a little light to get through, so when worn inside under fluorescent light, you see nothing.
“One out of every hundred thousand or so photons gets through — it might be one out of every hundred thousand or one of every million depending on the manufacturer of the solar filter,” Lombardi said. “It’s only when you’re looking at something extremely bright like the sun that you would get any amount of significant light coming through at all.”
