The August 21 total eclipse of the sun is already a widely-anticipated celestial event, and interest will likely only increase in the next four weeks.
While the effects of the moon passing between the earth and the sun will be noticeable in most of the U.S., its full effects -- with daylight turning to nighttime -- will only be seen in a 70 mile wide strip that runs the entire length of the continent, from Oregon to South Carolina.
No doubt most people with a clear shot at the eclipse will want to observe it, but NASA is cautioning that it needs to be done safely. Looking directly at the sun with the moon's shadow cast across it can cause permanent eye damage.
Already, businesses are hawking special filtered glasses for viewing the eclipse, as well as hand-held viewers. However, NASA recommends investigating to make sure these products meet the following standards:
- The products should have certification information with a designated ISO 12312-2 international standard
- The products should have the manufacturer’s name and address printed somewhere on the product
- The products should not be used if they are three years old or older, or have scratched or wrinkled lenses
NASA says consumers should not view the eclipse with homemade filters or ordinary sunglasses. Viewing products should also be purchased or obtained only from known, reputable souces.
Alex Young, associate director for science in the Heliophysics Science Division at NASA's Goddard Space Flight Center in Greenbelt, Maryland, says the space agency isn't trying to be the eclipse safety police. But the public, he says, needs to be cautioned about the potential dangers.
“It’s important that individuals take the responsibility to check they have the proper solar eclipse viewing glasses. With the eclipse a month away today, it’s prudent to practice ahead of time,” Young said.
NASA says as many as 6,800 libraries across the U.S. are distributing safety-certified glasses. Many of these local institutions are working with scientists to hold viewing events and activities before and during the eclipse.
Viewing it from the sky
Southwest Airlines says it will give away viewing glasses to passengers flying on one of Southwest's flights on August 21 that the airline says will cross through the total eclipse path at the right time.
Southwest has identified the following flights on August 21 that will provide a bird's eye view of the eclipse:
- Southwest flight 1375 departing Seattle-Tacoma at 09:05am PDT for St. Louis
- Southwest flight 1368 departing Portland at 09:05am PDT for St. Louis
- Southwest flight 1577 departing Denver at 10:20am MDT for St. Louis
- Southwest flight 301departing Denver at 10:20am MDT for Nashville
- Southwest flight 1969 departing Denver at 09:50am MDT for Atlanta
In fact, those who plan to view the eclipse from the air are the only ones who pretty much have a guaranteed view. The only thing that could ruin nature's show is a cloudy, overcast day. At 30,000 feet, you'll probably be above any potential cloud cover.