How to make an eclipse viewer

If you are planning to watch the solar eclipse on 8 April this year – whether you are in the path of totality or not – you will need some equipment to enjoy it fully.

The most important rule during an eclipse is not to look at the sun directly. The only time you can do so is during totality, the few minutes during which the sun’s light is entirely blocked by the moon. But for everyone in North America who lives outside of the 185 kilometre-wide path of totality, only a partial eclipse will be visible. And even for those within the path, there will be a few hours on either side of totality in which part of the fun is in watching the moon slowly creep across the sun.

You can use special solar filters, including eclipse glasses, to look at the sun directly. But you can also see the eclipse using simple viewers made from just a few things that you probably have lying around. Here is how to make two kinds of eclipse viewer.

How to make a pinhole camera

For this viewer, all you need is some paper, aluminium foil, scissors and a pen. Cut a hole in the middle of one piece of paper, and cover it in foil. Stick the foil in place and punch a small hole in the middle of it using a pen, needle or other sharp object. On the day of the eclipse, all you have to do is hold this up to the sun and place a second piece of paper on the ground underneath. A little bright dot will appear on the second piece of paper – this is a projection of the sun. As the eclipse progresses, and the moon covers more of the sun, you will see the shape of the dot change.

How to make a box eclipse viewer

The second kind of eclipse viewer works in the same way, but the projection appears inside a box instead of on the ground. For this, you need paper, foil, scissors and a cardboard box – a cereal box or shoe box will work well.

Line one inner side of the box with white paper. Then, cut two holes in the opposite side, spacing them far apart. Tape a piece of foil over one hole and poke a small hole in it. The other hole will be where you look through.

On the day of the eclipse, hold the viewer up to your eye, with the sun behind you. A projection of the sun should appear inside the box, on the white paper you lined it with.