A solar eclipse can be an event to remember, especially if you are fortunate enough to be present for a total eclipse. It is important to take care of your eyes when you watch a solar eclipse, however, as the sunlight can cause serious retinal damage. Fortunately, there are a number of safe ways to view one, ranging from wearing special glasses to using indirect observation through a so-called pinhole camera.
Most people are aware that looking directly at the sun is dangerous, since the light can cause retinal burns. If someone looks at the sun long enough, these burns can actually cause blindness. During a partial or annular eclipse, the light from the sun is still bright enough to hurt your eyes, even though the world is darker than usual. During a total eclipse, it is technically safe to look at the sun directly, but as soon as the eclipse moves out of totality, you can damage your eyes.
If you want to be able to look directly at the sun during an eclipse, you will need special glasses. Unlike sunglasses, eclipse glasses filter out more of the sun's rays, making it safe to look at the sun directly for several minutes. Heavy duty welding glasses can also be used as eclipse glasses, if you have access to a set. Many science stores sell eclipse glasses, and observatories sometimes hand them out to groups who gather to watch the event.
You can also use a mirror to project the image of the eclipse onto a surface such as the side of a house. Be careful when doing this, as you do not want to flash light into someone's face or eyes. To use a mirror, use heavy tape to mask out most of the surface of a hand mirror, leaving around 1 inch (2.54 cm) of the mirror clear. Point the mirror at the sun and then angle it at a surface so that you can watch the eclipse in projected form.
A pinhole camera will also allow you to watch a solar eclipse safely. To do this, cut a small hole in a piece of heavy paper or cardboard. Stand with your back to the sun and hold the piece of paper with the pinhole over a white sheet of paper. With some adjustment, a small image of the sun will appear. You can change the focus by moving the top sheet of paper around until the picture becomes crisp, and then you can enjoy the solar eclipse without the risk of eye damage.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.