UA Astronomer Offers Safety Tips for Viewing Solar Eclipse

TUSCALOOSA, Ala. — Although the state of Alabama will not be under a total solar eclipse Aug. 21, there is still the opportunity to view a partial solar eclipse.

Astronomers at The University of Alabama urge people to view the phases of the eclipse safely by not looking directly at the sun.

“The sun light is just as dangerous during an eclipse as any other day, but we tend not to want to look directly at the sun normally,” said Dr. William C. Keel, UA professor of physics and astronomy.

For the first time in 99 years, a total solar eclipse will move from coast to coast across the continental United States Aug. 21, and all of North America will experience a partial eclipse.

Alabama, though, will be in a partial eclipse with ranges from 80 percent of the sun covered by the moon near Mobile to 98 percent coverage in the northeast corner of the state, Keel said.

The best way to view the partial solar eclipse over Alabama that day are pinhole projections, solar filters and projections from telescopes or binoculars, he said.

• Pinhole projection – In this method, sunlight passing through a small hole makes an image of the sun on whatever surface is used as a screen. The image of the sun gets larger the further the screen is from the hole, and only small holes will work, Keel said. A puncture in cardboard or aluminum foil works well, but any material works, and even gaps in tree leaves can project the eclipse onto the ground, he said.

• Solar filters – Solar filters are thin films in a cardboard or plastic mount. Only special-purpose solar filters, such as eclipse glasses or handheld solar viewers, are sufficient to look at the sun. Several vendors can provide safe solar filters, Keel said.

• Projections through lenses – Most telescopes and binoculars can focus enough to project a sharp image of the sun onto a sheet behind the eyepiece. Telescopes with eyepieces at a 90-degree angle from the tube offer easy ways to shade the image for clearer views, Keel said. Those choosing this method need to be careful to keep anyone from looking directly through the eyepiece to avoid severe damage to the eye.

For a partial eclipse, Keel said it takes about 80 percent coverage for people on the ground to notice the eclipse without one of the other three methods, Keel said.

“A partial eclipse will look like the moon is taking a bite out of the sun,” he said.

Keel, along with most of the astronomers on campus, will travel into the 70-mile wide swath of the total eclipse that will extend from Oregon to South Carolina, with parts of Tennessee the closest to Alabama. The eclipse is an opportunity to experience a rare event, he said.

“It’s just a spectacle that anyone can witness,” Keel said. “This adds to the mystique because you can go so long between events.”

The next solar eclipse across North America will be April 8, 2024, and will cross from Mexico to New England, but a total eclipse will not pass over Alabama. That will not happen in Alabama until Aug. 12, 2045, as a total eclipse encompasses Tuscaloosa, Montgomery, Dothan and all points in between, Keel said.