Make Pinhole Projector to View Eclipse
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This is probably the most important part of this website. If you ever want to view an eclipse, the first
thing you must know is this:
Never view the sun with the naked eye or with any optical device, such as binoculars or a telescope!
This is more than advice. Why? As a kid, did you ever take a magnifying glass out into the sun and burn
leaves? If so, you probably remember that when the focused sunlight coming through the lens was
refracted and concentrated to a small spot, the energy available there was truly remarkable. Guess
what? You have a lens just like that in your eye. If you look at the sun, your eye-lens will concentrate the
sun's light and focus it to a very small spot on the back of your retina. This can cause permanent eye
damage or blindness. Additionally, there are no pain sensors back there so you won't even know it's
happening! Have I scared the willies out of you? Good!
Pinhole Projector
There are safe ways to view the sun. The simplest requires only a long box (at least 6 feet long), a
piece of aluminum foil, a pin, and a sheet of white paper.
The length of the box is important. The longer the box, the bigger the pinhole image. To find the size of
the image, multiply the length of the box by the number 0.00873. For a box that is 1 meter long, the
image will be 0.00873 meters (or 8.77 mm) in diameter. If your box is 5 feet (60 inches) long, your solar
image will be 60 x 0.00873 = 0.52 inches in diameter. If you want to round things off, the size of the
image is about 1/100th the length of the box.
If you can't find a long box or tube, you can tape together two or more boxes to make a longer one. In the
illustrations below, we found that taping together two triangular UPS shipping tubes works well. Of
course, if you do this, you must cut out the cardboard at the ends of the tube in the middle!
thing you must know is this:
Never view the sun with the naked eye or with any optical device, such as binoculars or a telescope!
This is more than advice. Why? As a kid, did you ever take a magnifying glass out into the sun and burn
leaves? If so, you probably remember that when the focused sunlight coming through the lens was
refracted and concentrated to a small spot, the energy available there was truly remarkable. Guess
what? You have a lens just like that in your eye. If you look at the sun, your eye-lens will concentrate the
sun's light and focus it to a very small spot on the back of your retina. This can cause permanent eye
damage or blindness. Additionally, there are no pain sensors back there so you won't even know it's
happening! Have I scared the willies out of you? Good!
Pinhole Projector
There are safe ways to view the sun. The simplest requires only a long box (at least 6 feet long), a
piece of aluminum foil, a pin, and a sheet of white paper.
The length of the box is important. The longer the box, the bigger the pinhole image. To find the size of
the image, multiply the length of the box by the number 0.00873. For a box that is 1 meter long, the
image will be 0.00873 meters (or 8.77 mm) in diameter. If your box is 5 feet (60 inches) long, your solar
image will be 60 x 0.00873 = 0.52 inches in diameter. If you want to round things off, the size of the
image is about 1/100th the length of the box.
If you can't find a long box or tube, you can tape together two or more boxes to make a longer one. In the
illustrations below, we found that taping together two triangular UPS shipping tubes works well. Of
course, if you do this, you must cut out the cardboard at the ends of the tube in the middle!
1) Find or make a long box or tube
If you can't find a long box or tube, you can tape together two or more boxes to make
a longer one. We found that taping together two triangular UPS shipping tubes
works well. Cut out the cardboard at the ends of the tube and tape them together
with duct tape in the middle.
a longer one. We found that taping together two triangular UPS shipping tubes
works well. Cut out the cardboard at the ends of the tube and tape them together
with duct tape in the middle.
2) Cut a hole in the center of one end of the box.
3) Tape a piece of foil over the hole.
4) Poke a small hole in the foil with a pin.
3) Tape a piece of foil over the hole.
4) Poke a small hole in the foil with a pin.
5) Cut a viewing hole in the side of the box.
Cut a viewing hole in the side of the box near the paper, then put a piece of white
paper inside the end of the box near the viewing portal.
Point the end of the box with the pinhole at the sun so that you see a round
image on the paper at the other end. If you are having trouble pointing, look at
the shadow of the box on the ground. Move the box so that the shadow looks like
the end of the box (so the sides are not casting a shadow). The round spot of
light you see on the paper is a pinhole image of the sun. Do not look through the
pinhole at the sun! Look only at the image on the paper.
paper inside the end of the box near the viewing portal.
Point the end of the box with the pinhole at the sun so that you see a round
image on the paper at the other end. If you are having trouble pointing, look at
the shadow of the box on the ground. Move the box so that the shadow looks like
the end of the box (so the sides are not casting a shadow). The round spot of
light you see on the paper is a pinhole image of the sun. Do not look through the
pinhole at the sun! Look only at the image on the paper.
