Joel Hunter, MD Refractive Surgeon, Hunter Vision Updated 08/07/17 10:51 AM
On August 21, 2017 the most amazing celestial phenomenon of them all is going on tour through the United States. It’s going to travel smack dab through the middle of the country on a path from South Carolina to Oregon. That means even if you live in the southern or northern US, you’ve still got the chance to see a solar eclipse where the moon covers at least 75% of the sun. Here in Orlando, we’ll be in position at 2:50 p.m. to see an eclipse with a magnitude of close to 0.9 (i.e. about 90% of the sun covered.) How fun!
Now, granted it could rain at that time—in which case it won’t change my plans to be outside if only to angrily shout at the clouds—but if it doesn’t, we should be prepared for good times. How do you prepare to watch this? More specifically, how do you look at a phenomenon of the sun, when you can’t look at the sun without risking blindness? If you’ve found this article and made it through the first two paragraphs, congratulations! I’ve got answers.
Sunglasses won’t cut it. Maybe you have really, super dark sunglasses. Those nearly black glasses only let about 10% of daylight through. In that case, you’re not even close! I did the math on this to compare them to the type of glasses required to safely look at a solar eclipse. Those ultra-dark sunglasses still let about 30,000 times more light in than the type of glasses needed to watch a solar eclipse. No, the glasses you need have a special ISO approval (the international board which determines safety standards for everything from healthcare to helmets to hamburgers). They also look ridiculous. If you’re worried your friends will make fun of you, just remember how much easier it is to deal with mockery than it is to deal with blind, scorched retinas. And then remember if your friends make fun of you then they’re not your true friends. I learned that from my mom and it helped me a lot as a child.
If you’re wondering where to get those eclipse glasses, a search on Amazon will (as always) deliver several options. As long as they have ISO approval, you’re good. If you’re a procrastinator, it’s a good bet some of the entrepreneurial minds around town will also be selling eclipse glasses at an insane mark up. On the upside, since they only cost about $20 for a 10-pack of eclipse glasses, even the overpriced ones probably won’t cost more than a fast food meal. And they’ll definitely cost less than buying new retinas, which have the price of whatever is necessary to build a time machine and travel 50 or 100 years into the future.
There’s one other option for viewing this solar eclipse (outside of the very niche set ups like specific types of welding goggles or solar filter telescopes). It’s the good old-fashion pinhole camera. If you’re caught on August 21st with no eclipse glasses, then you can watch the eclipse (kind of) with just a couple pieces of paper. Using the same trick from old camera obscura photography, a pinhole camera made of paper can project an impressively clear “live photo” of the eclipse onto another sheet of paper. You can safely view the eclipse by watching the tiny movie you’ve created. The downside of not watching it directly is offset heavily by the praise your friends will rain on you for your inventive genius. Those are your true friends.
Editor’s note: CNN recently ran a story on the dangers of buying bogus solar eclipse glasses. The short version is that some manufacturers are stamping ISO approval seals on their glasses at will. Here is a list of approved solar eclipse glasses manufacturers from that article.