The principles of pinhole projection can also be used with an inverted telescope or binoculars. Direct viewing requires specialized filters and can seriously damage the eye.
As of Saturday, August 19, 2017
The Dalles is among those areas that have reported a shortage of eclipse viewing glasses.
While genuine protective eyewear is the only safe way to directly view the eclipse, one alternative to glasses includes a homemade pinhole projector.
A video on how to make a pinhole projector to view the eclipse is available on OR emergency management websites and directly at https://youtu.be/vWMf5rYDgpc.
Here are the details:
What you need
• Cardboard box (a cereal box is used in the video)
• Sheet of white paper
• Aluminum foil
• Pen or pencil
• Pin or thumbtack
Take your box and trace its bottom on your sheet of paper. Cut out the rectangle you just traced and tape it to the bottom of the inside of your box.
This will be your projection screen.
Close the top of the box and cut two holes, one on right and and another on the left edges of the top panel.
Cut a piece of aluminum foil to cover one of the holes and tape it in place.
Poke a hole in the middle of the piece of foil.
Use your projector
Take your pinhole projector outside and face away from the sun so that its light shines into the pinhole.
Look through the hole you did not cover and you will see the sun projected on the white piece of paper inside the box.
The longer the box, the larger the image will be.
Easier and better for group viewing is skipping the box and punching a pinhole into a sheet of paper and then simply projecting the sunlight through that pinhole onto another sheet of white paper on the ground.
The image of the sun won't be as vivid as it is projected inside a dark box, but it should work just fine if you have clear skies and bright sunshine on Monday.