How to Build a Solar Eclipse Viewer

Eclipse at totality

Eclipses have fascinated human beings for centuries. Those of us who've been fortunate to witness one as a child know the wonder and fear that primitive humans felt when the sun, bringer of light and warmth, suddenly disappeared in the middle of the day as if something were eating it away. We can share that thrill with our children if we make a project of building a simple viewer to watch the eclipse. Although it's safe to look at the eclipse at totality, looking directly at the sun at any other time can seriously burn the retina of the eye. Since totality lasts for a few minutes at best, a viewer is more than fun--it's a necessity.

Things You'll Need

• Boxes
• Cardboard or white board
• White paper
• Aluminum foil
• Glue stick or rubber cement
• Safety pin
• Scissors or craft knife

Instructions

1. Explain how a solar eclipse happens. If kids understand that the phases (as well as lunar eclipses) of the moon are due to the shadow of the earth traveling across the moon, it's easy to understand that a solar eclipse is due to the moon getting in the way of the sun. The ability to imagine the earth moving through space in relation to the moon and stars is what ancient humans lacked--and what gave rise to all the marvelous folk tales and scary superstitions about this fairly common (in celestial terms) event.

2. Assemble your materials. You'll need two shipping tubes to make an overall length of at least six feet, a bit of tin foil, a sheet of white paper, glue and some packing tape. You can make a smaller viewer with a big cardboard box or an even simpler one with two pieces of whiteboard or cardboard. The shipping tube model is most like a telescope and will be the most adventurous project for children ages eight and up.

3. 

   Establish an aperture, or opening, to view the eclipse on one end of your tube or on one side of your box near the bottom or closed end. Cut a hole and cover it with a bit of tin foil. Then prick the foil with a pin once. This will allow the image of the sun to enter your viewer.

4. Make a view finder. Cut a hole out of the side of the shipping tube on the end opposite the aperture. If you're using a big cardboard box, adjust the box to sit on your shoulders with the aperture above and behind your head. Tape the flaps open and cut "saddles" for your shoulders on facing flaps.

5. Position your "film." Since your viewer is basically a simple camera, admitting light through an aperture, you need a place for the image to register. Tape or glue a piece of white paper opposite the foil aperture, either on the inside base of the shipping tube model or the inside wall of the big box opposite the aperture.

6. 

   Point the foil-covered aperture at the sun. Start watching through the viewer or put the big box on your shoulders.

Tips & Warnings

• If you must use your camera or other optical instrument to view an eclipse, be sure to have the correct filter. Purchase an eclipse filter or welding filter from a camera or optical source that specializes in such instruments.

• Make a simple viewer with two pieces of whiteboard or cardboard. Put a foil aperture on one and hold it above the white surface of the second. Or just put a white paper in dappled shade--you'll see dozens of eclipse images through the apertures formed by the rustling leaves. At totality, the leaves will be still because the temperature will drop like it does at sunset and the wind will drop off.

• Partial eclipses happen every few years in any given locality. Total eclipses are more rare, often as much as fifty years apart. Check NASA's web site for a schedule of future solar eclipses for your city with maps of locations where total eclipses can be viewed.

• Never use sunglasses or "smoked glass" to watch an eclipse. Retinas burn quickly and painlessly.

Resources

• Easy solar eclipse viewers
• NASA's perpetual solar eclipse calendar