How to safely watch a solar eclipse
For about two minutes on Aug. 21, millions of Americans will see stars shine, birds return to their roosts and nocturnal insects buzz to life in the middle of the afternoon as the moon briefly eclipses the sun and its shadow is cast over the Earth.
For the first time since 1918, the “path of totality,” a 70-mile wide track where the sun will be perfectly blocked by the moon, will stretch coast-to-coast – from Oregon to South Carolina, including the southwestern tip of North Carolina.
The Triangle is close enough to the path of totality that residents will see a partial eclipse, where up to 93 percent of the sun will be blocked. Sounds impressive, but those who think they can stay home and still have most of the eclipse experience will likely be disappointed.
“Bottom line for anyone planning on staying in the Triangle to observe the eclipse: Lower your expectations. Don’t stay here because you think it’ll be almost as good as totality,” said Amy Sayle, astronomy educator at Morehead Planetarium and Science Center. “Ninety-three percent eclipsed will not be 93 percent of the full experience.”
In fact, many Triangle residents may not even realize that the eclipse is happening. So much light will pour around the moon as it passes in front of the sun that the mid-day darkness that people associate with an eclipse simply won’t happen here.
“Because the sun is so bright, you really won’t see anything,” said Rachel Smith, an astronomy professor at Appalachian State University in Boone. “It won’t get very dark at all. It won’t even be perceptible.”
Still, a partial eclipse is an uncommon occurrence and worth observing, if you know to look for it. In the Triangle, the partial eclipse will begin at 1:16 p.m. on Aug. 21, but the best time to look will be around 2:44 p.m., when it reaches its maximum for several minutes.
But don’t expect to simply glance up at the sun. The only time it is safe to look at the eclipse without eye protection is during the brief period of totality, which won’t happen here. It is not safe to look directly at the sun any other time, including any partial eclipse, because the intense brightness can cause permanent damage to the retinas of the eyes.
One option is to look through certified solar filters, such as eclipse glasses or hand-held viewers. Certified solar glasses can be purchased for a few dollars and block out a large portion of brightness from the sun. Regular sunglasses are NOT safe for looking directly at the sun.
An equally safe method is to build a pinhole projector that will project a small shadow of the eclipse onto the ground below. Plans to build several different styles can be downloaded for free from the NASA eclipse website, eclipse2017.nasa.gov. Smith said that this is an “easy to do” option if you forget to plan ahead.
For those who can’t make it outdoors or travel to the path of totality, NASA will be live-streaming the eclipse on its website and broadcast live television coverage from 1 to 4 p.m. with NASA experts stationed along the path of totality.
First in 38 years
Total solar eclipses occur about every year and a half on Earth, but they are often only seen in remote places with few inhabitants.
“Total eclipses of the sun happen every year all over the world,” Smith said. “It’s just that they don’t happen where you are all the time.”
The last time a total solar eclipse was visible from the continental U.S., Jimmy Carter was president and Le Freak by CHIC was spinning at discos. Every solar eclipse seen from the continental U.S. since then has only been a partial one. That is one reason for the extra hype surrounding this year’s event.
But how can the moon, which is so much smaller than the sun, block all of its solar rays? The answer has to do with perspective.
The sun is indeed 400 times larger than the moon, but it is also 400 times farther away. When standing on Earth, this provides the illusion that both are equal in size, making a total eclipse possible.
Other planets also experience solar eclipses; NASA’s Curiosity and Opportunity rovers have photographed them from the surface of Mars. But due to the small size of the Martian moons, these eclipses – called annular eclipses – “look like little eyeballs,” according to Smith, and lack the environmental effects seen and felt on Earth.
According to NASA, 12.2 million Americans live within the 2017 path of totality, and many more plan on traveling to witness the complete celestial phenomenon.
“Many people want to travel to be in the path of totality because the skies will get dark, and then you can see the environmental phenomenon like birds going to roost, flowers closing, and all those cool things,” said Smith, who also heads the Astronomy and Astrophysics Research Lab at the N.C. Museum of Natural Sciences in Raleigh.
Smith and her colleagues from the museum are traveling to Sylva in far western North Carolina where they will provide a feed for a live-stream of the total solar eclipse at the museum’s theater in Raleigh. She says it is rare for so much of the country to have the opportunity to experience such a special celestial event with the naked – but protected – eye.
As an astronomer, Smith has seen all sorts of celestial events, but she’s never experienced a total eclipse in person.
“Having the chance to be immersed in the surrounding environment in the path of totality should be really amazing,” said Smith. “The sky going to twilight, the planets becoming visible, animals and plants changing behaviors, rings of light around the Moon – I can’t wait to see it, and hope for clear weather!”
The next total solar eclipse visible from the U.S. will be in 2024, but the next coast-to-coast one will not occur until 2045.
Jeremy Frieling: 919-829-4826