[Three homemade pinhole projection systems for the August 21 solar eclipse]
If you plan on watching the August 21 solar eclipse (and why wouldn’t you?) now is the time to plan on viewing it SAFELY! The sun will be about 2/3 eclipsed as seen from here in Connecticut at its greatest extent, which means it will NOT be safe to look at with an unaided eye. If you have purchased solar eclipse glasses, that’s great. If not, you can still safely view the eclipse using a pinhole projection system, like the ones shown above.
[How to align a projection system and a typical project image]
In each case, you need to make a literal pinhole in one end (poking one into aluminum foil is more reliable than cardboard, as shown) and a white screen on which to catch the image. You point the pinhole end at the sun, and minimize the shadow to align the tube or box (as shown above). Your image will be relatively small and depends on the length of the tube or box. The roughly 1 meter long systems shown above give a projected image that is about 1 cm in diameter.
For more information on how to make your own projection systems, see the following websites: