Hack the Eclipse ! Here are some ideas for a DIY Viewer
Written by Lola Rizer on August 18, 2017
All you need is cardboard aluminum, foil, and tape, or a mirror and an envelope,” she explains.
Cut a hole in the middle of one sheet of card stock, tape the edges of a tin foil section over it, then carefully pierce the center of the foil with the needle. ” You’re not even looking at the sun. You’re just pointing the box in that direction.”
The box exploits a property of light called diffraction to bend and magnify the light. In this case, that’s the eclipsing sun.
Chouinard’s next trick involves even less work.
“The second thing you can do is slide a mirror into an envelope and then you cut a half inch hole in the envelope. Then you just aim the mirror at the sun and it will reflect back and bounce off of whatever you have, whether it’s the wall or the ground.”
According to AstroSociety.org, this method is relatively safe and allows many people to view the shadow of the sun at once. Here are their step-by-step instructions on how to safely create and use a solar projector.
- Make a cardboard collar to fit around the front end of the binocular or telescope (see their diagram). This shades the area where the image will be from sunlight and (in the case of binoculars) will cover the lens which you are not using.
- Focus the binoculars or telescope on infinity by looking at a distant object (but not the sun) in the normal way (if you are using a telescope, use a low-magnification eyepiece).
- Point the binoculars or telescope at the Sun (do not look through the instrument to do this), as shown in the figure, and adjust the direction of pointing until the image of the sun appears on the screen. This may take a minute or two. One useful trick is to watch the shadow of the binoculars or telescope tube: if pointed directly toward the sun, then the sides of the tube will cast no shadows, and the instrument’s shadow will be as small as it can be.
- Move the screen toward or away from the eyepiece until the image of the sun fits neatly in the middle, and adjust its tilt until the sun’s image is circular.
- Jiggle the binoculars or telescope very slightly. Any specks on the image of the sun which don’t jiggle along with the image when you do this are specks in the binoculars or telescope (or smudges on the screen), and not spots on the sun itself.
If you don’t have a telescope or binoculars, don’t worry. With just a few simple materials – two pieces of white card stock, a piece of aluminum foil scotch tape and a pin or a paper clip – you can make a pinhole camera that will project the sun’s image. NASA’s Jet Propulsion Laboratory has step-by-step instructions here.
Even if you don’t have any materials on hand, you can still see the eclipse by fashioning a rudimentary pinhole camera from your own hands. According to the American Astronomical Society, you can cross the outstretched, slightly open fingers of one hand over the outstretched, slightly open fingers of the other.
When your back is to the sun, the little spaces between your fingers will project a grid of small images on the ground. During the partial phases of the solar eclipse, these images will reveal the sun’s crescent shape.