How to Observe the Eclipse

It is never safe to look directly at the sun, even when it is in eclipse.  So how can you observe the eclipse if you can’t look at it?

One option is eclipse glasses (note, not sunglasses).  These look like 3D movie glasses, except the lenses are made from specially coated mylar, the same stuff we use on our solar filters for the telescopes.  The mylar will filter out 99.99% of the photons shining on it, temporarily changing the intensity of the sun to a reasonable amount for eyes.  Be sure that you get certified glasses, because uncertified ones may not work and you could still damage your eyes.

If you don’t have any fancy equipment or glasses, there’s still a way you could get a better look.  Using two pieces of paper or cardstock, you can make a pinhole projector.

Pinhole projector diagram

Use a pin to poke a hole in one sheet of paper.  Don’t make it any bigger than the pin, you only need to allow a tiny amount of light through the hole.  Place the second sheet on the ground outside, and hold the first about a foot above it.  The light will come through the hole and project an image on the other side to make an image. (You can find fancier instructions with a quick online search, just make sure you never look through the pinhole to the sun, you will definitely hurt your eyes.)  To make the image bigger, move the sheet with the hole further away.  

Why doesn’t the image get bigger if you use a bigger hole? Pinhole projectors make use the physical properties of light.  Light rays from the sun are parallel, but there is a lot of ambient light in our atmosphere bouncing off of clouds, trees, buildings etc.  If you point it at the sky, pinholes will only allow the parallel light from the sun to reach through to the other side, giving you an image of the partial eclipse. If the pinhole is bigger, more light can get through and the image will blur to the point you can’t see it anymore.  

Wherever you are, make sure to be safe while you observe the eclipse.

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