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September 2010



  Observing the Sun Safely

Safe Viewing | Observing the Sun | The Sun today | Sun Activities

When most people think of astronomers observing the sky, they picture it at night. Many astronomers, both professional and amateur, also turn their telescopes to the Sun. While this should only be attempted under the safest of circumstances, solar observing can be quite rewarding. By practicing safe viewing techniques, one can even see sunspots on the Sun - dark, cool areas often several times the size of the Earth!

It is extremely dangerous to look at the sun through unprotected binoculars, telescope or even with the naked eye. Doing so can lead to permanent damage of the eyes, and perhaps even blindness. Here are some guidelines for observing the Sun safely:

Safe Viewing
Unsafe Viewing
1. Pinhole Projection Method 1. Naked eyes
2. Solar Filters 2. Standard or polarized sunglasses
3. Welder's Glass (No. 14) 3. Improperly filtered binoculars or telescope

Students using a solar filter to safely view the Sun and draw sunspots.

One alternative available to teachers is to project an image of the sun from binoculars or telescope onto a screen or a piece of white bristol board. When attempting this, only use a refracting telescope, and not a reflecting telescope, as a reflecting telescope will heat up too quickly.

Another method especially suitable for teachers is the "pinhole-mirror projection." Using a small pocket mirror, cover up the entire mirror with masking tape except for a small (say, 6mm by 6mm) square.

Position the mirror against a wall or ledge, and turn it so that it can reflect incoming sunlight onto a viewing screen, a wall or the ceiling. The larger the distance from the mirror to the viewing screen, the larger the image of the sun, but the dimmer the image will be.

Solar eclipses, especially, can be viewed in complete safety by a class of students in a darkened room. BE CAREFUL, however, to NOT shine the reflected sunlight into anyone's eyes!

Some stores which specialize in selling telescopes and accessories, also carry solar viewing glasses. These are often a less expensive alternative, at less than $5.00 per pair. Visit your local telescope supplier for more details.


Solar viewing glasses are often a less expensive option.

For more details on how to observe the Sun safely, visit the following websites:

If you do not have the resources available to observe the sun directly, it can be observed online:

Looking for activities involving the Sun?

created by the CASCA education Webteam, (2009)


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