If you live in the United States and missed the last total solar eclipse of 2017, good news! You’re about to get another chance. On April 8, a total solar eclipse will occur in Texas and Midwestern states. Remember, during a solar eclipse, the moon’s shadow falls on Earth. It will look weird if you are in this shade. But also great.
Even if you’re not on the path to totality, you can still see something. All continental countries will see at least a partial solar eclipse. (Check out the map on NASA’s eclipse page.) Do I need to tell you this? Never look at the sun without special glasses, even if the sun is mostly blocked by the moon. You can still find some safe solar watchers before big events.
But there’s another way to view the eclipse without glasses: using a pinhole projector. It’s super simple to make and easy to use. All you need is something as flat as cardboard. Then poke a hole in it with a pin. That’s pretty much it. When sunlight passes through the hole, it projects an image onto some flat surface, such as a sidewalk.
If you do this on a normal day, you will see a circular spot of light. You might think this is because the hole is round. But during a solar eclipse, you’ll see a crescent shape created by the moon passing in front of the sun. It’s great and safe for your eyes.
In fact, you don’t even need make Pinhole Observers – They are already all around us. If you stand under a tree, the small spaces between the leaves will act as pinholes, projecting a bunch of small crescent-shaped images. Here are the photos I took during the 2017 solar eclipse:
Pinhole fun
Just for fun, here’s a question for you. Most pin holes are circular (because the pin has a cylindrical shaft). But what if you replaced the round hole with a square hole? What shape would the round sun look like when projected onto the ground? Will it be a circle? Will it be a square? Or maybe it will be a squirrel! What about the triangular holes? So what happens?
I actually have a card from PUNCH (Politometer for Unifying the Corona and Heliosphere) that demonstrates this with three holes (circle, triangle, and square). check it out.