Eclipse viewing for the cautious astronomerPosted: August 20, 2017
Super excited about the eclipse tomorrow, but worried about your eyeballs? You’re not alone. My physicist husband wouldn’t trust anything short of a welder’s glasses with a suitably high rating, and even then he’d merely feel reassured that he could quantify the damage, nothing else.
In 1994, we witnessed a partial eclipse in St. Louis, outside the physics department at Washington University. My husband said, “You can tell the theorists from the astronomers. The theorists are looking at the sun through various viewers and dark glass; the astronomers aren’t looking at the sun at all.”
Well, kids, here’s what I learned from those cautious astronomers, and I’m passing this along to you because it’s cool: you can make a pinhole camera right on your own stomach. I don’t mean those big clunky boxes you see kids wearing in old photos — that’s overkill. This is much simpler, and it really works. I did it in 1994.
Wear a single-color shirt — white is good, but anything will do. You just don’t want words or a pattern interfering with your projection. Your stomach is the movie screen.
Form a little square “pinhole” by pressing the tips of your thumbs and index fingers together. It doesn’t have to be super tiny, just whatever gap is naturally there. Hold that pinhole a foot or so in front of your stomach and aim it toward the sun. It takes a little work, moving it in and out to find the best focal length, but you will find that you can project an image of the diminishing sun onto your belly.
Another unexpected detail: the gaps in overhead foliage also act as pinhole cameras. The ground beneath the trees will be covered in hundreds of dancing crescents!
I know there will be folks who won’t feel like they’ve seen it unless they SEE it through a viewer of some kind. I just wanted to reassure the eyesight-risk-averse among us that there are fun options. We can’t all throw caution to the wind like those devil-may-care theoretical physicists.