If you are in the path of the total solar eclipse, you might well be planning on taking a look. Who wouldn’t want to see this spooky sky situation? So how do we do it safely?
The only safe way to look directly at the sun is through a special type of eye protecting goggles/face shield. These include
- Shade No. 14 Welder’s glasses
- Eye coverings made from aluminized Mylar filters. These must be pristine, any scratches or damage can let the light through and seriously hurt your eyes. These are what eclipse glasses or hand-held viewers are made from.
You can find safe sources of eclipse glasses here. Be wary of counterfeits.
If you are using eclipse glasses, etc., make sure that they are made from the right materials before you put them on. The American Astronomical Society advises that you check the label on the inside for a safety mark. If the glasses are safe, they will state that they comply with the ISO 12312-2 international standard for safe viewing.
If you don’t have welding goggles or safety certified eclipse glasses, you can catch the eclipse indirectly with a pinhole viewer. This is actually a pretty cool trick that dates way back in history.
Turn your back to the sun, place a piece of white paper or cloth on the ground or a flat surface. With your back to the sun, hold something with a small hole (a piece of cardboard, a straw hat, even a colander) over the paper. Still facing away from the sun, let it shine through the tiny hole. Keeping the pin hole in place, look at the piece of paper on the ground. In the middle of the shadow, you will be able to see a projection of the sun! Nice huh? Do not look towards the sun through the tiny hole. Look at the paper on the ground or on a surface.
Do not look at the sun with your naked eyes, with ordinary eye glasses, spectacles, sunglasses, binoculars, telescope, camera view finder or a phone camera. We all like to think our reflexes are that of a trained acrobat or the like. In reality, you will not be able to look away fast enough.
The sun is so bright that the intensity of the light can overwhelm the delicate light detecting cells in your retina. This will permanently damage them. Think about how your eyes feel when you get dazzled from reflections off sand, glass or pavement. A direct hit from the sun is not going to do your photoreceptors any good. In fact, often when ophthalmologists examine somebody’s retina after looking at the sun, they can see patches of damage.
For more information we suggest the following:
Writing in the Journal of the American Medical Association (JAMA) ophthalmologists Neil Bressler, Jun Kong and Fernando Arévalo suggest some vision-safe ways to see the sun.
NASA FAQ on what happens during an eclipse and some safety tips.
The American Astronomical Society has a great resource for how to view the eclipse.
