U-M astronomer Richard G. Teske emphasizes that it is dangerous to look directly at the sun and moon while observing the eclipse. The sun’s surface is so bright that even a brief glance might permanently impair vision. “Even if you observe through something dark like multiple sunglasses or stacked photographic negatives, you are taking a chance with your eyes,” he warns.
“The safest way to view the eclipse is to do it indirectly. Punch a hole about half the size of a dime in a large sheet of cardboard. Even though the hole is small, be sure to use a sheet of cardboard big enough to cast a large shadow on the ground. Lay a white pillowcase or sheet of paper on the ground at your feet. Move the cardboard around until an image of the sun appears on the pillowcase on the ground. This way, you can safely watch the progression of the solar eclipse without risking damage to your eyes.”
