An August eclipse was once responsible for thousands of deaths. During the Peloponnesian War, the Athenian general Nicias delayed a critical retreat because he interpreted an eclipse as a warning to keep his troops in place. A disastrous defeat followed, the beginning of the end of Athens’ time as the center of western civilization.
We’re, um, pretty sure nothing so catastrophic will happen with Monday’s Great American Eclipse, but there is one threat. Looking directly at the sun without proper eye protection can cause serious eye damage and even blindness.
With regulation eclipse glasses in short supply throughout Seattle, one solution is a homemade pinhole projector. You still won’t be able to look directly at the sun, but you will be able to watch a projected image of the moon eclipse it using a device you can construct with just a cereal box, scissors, and aluminum foil.
The steps are simple: Take a regular cereal box and line the bottom flap with white paper. This will eventually be your screen. Next, seal the top flap and cut out approximately 1-inch squares from each side of it. Cover one of these holes with aluminum foil and tape it in place, making sure that no light can permeate the edges.
Use a nail to poke a hole in the aluminum foil. When the eclipse begins, line up this hole with the sun and look through the other square. The light will shine through the hole onto the white paper lining the bottom. As the moon begins its transit across the sun, the point of light on your screen will become similarly occluded, providing essentially a low-fi movie version of what’s happening above us.
While it is safe to look directly at the eclipse during “totality,” the period when the sun is completely blocked by the moon, here in Seattle we will only receive 92 percent coverage at the peak. If you can’t get your hands on the direct observation glasses, be sure to bring one of these pinhole projectors with you to any of Seattle’s many prime viewing locations. And try to keep a calmer head than Nicias did.
Check out this NASA video for more directions on making your personal DIY eclipse projector.