Solar Eclipse How to View an Eclipse


This is probably the most important part of this website. If you ever want to view a solar eclipse—whether itís total, annular, or partial—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!

(Okay, there's one time you can look at the sun: that's during a total eclipse when the moon completely blocks the face of the sun, allowing the magnificent corona to be seen. This is totality, which lasts from a few seconds to a few minutes. The instant the moon begins to move off the sun's face, you must go back to a safe viewing technique.)

Watch this video, How to Build a SunViewer, for a safe way to watch activity on the sun by projecting the sunís image. The video discusses watching transits of Venus and Mercuryóbut the viewer works equally well for solar eclipses.

Exploratorium TV 2 player



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 0.0093. For a box that is 1 meter long, the image will be 0.0093 meters (or 9.3 mm) in diameter. If your box is 5 feet (60 inches) long, your solar image will be 60 x 0.0093 = 0.56 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.

How-to images
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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.

More How-To Images
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5) Cut a viewing hole in the side of the box.

Still More How-›o Images
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6) 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 of the box 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.

Quick and Easy

How-To Images
(Click on the image for expanded instructions)

If you want, you can use only two pieces of cardboard--one piece colored white to project on to, and the other with a pinhole. Hold up the pinhole as far from the screen as you can. Remember, the farther you are from the screen, the bigger your image.

Photo:Tree ShadowsPhoto: Use Your HandsGetting even more basic, you can use your own hands. Just hold up both hands with your fingers overlapping at right angles. The holes between your fingers make pinholes.

If you have some shade trees in your location, try looking at the images of the sun coming through the holes formed by the leaves. A piece of white posterboard is all you may need to have a great viewing session!

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