Hundreds of thousands of people are expected to visit eastern Idaho for Monday’s total solar eclipse — the first to to span the coastal United States since 1918.
Though the event’s rarity is a draw, it also means many likely don’t have experience viewing total eclipses safely and effectively.
Normal sunglasses won’t be enough to protect eyes from solar rays, nor will cameras be safe without additional accessories.
Idaho National Laboratory Department Manager Carl Stoots, the lab’s “resident astrophotographer,” has observed celestial events for nearly two decades. He gave an eclipse safety presentation to INL employees, though details also apply to the general eclipse-viewing public.
“It’s a very dynamic event and you need to be well-prepared and organized because it’s a one-shot deal. It won’t happen again for a long time,” Stoots said. “No matter how you look at it, unless you chase them around the world, you’ll probably experience one eclipse in a lifetime.”
Stoots became interested in astrophotography 18 years ago after purchasing a telescope and a book about astronomy.
“I realized I couldn’t see what the pretty pictures in books were displaying, just fuzzy patches, and I was frustrated with that. One thing led to another, and I started taking photos, improving techniques and equipment,” Stoots said.
He built an observatory in his backyard with an elaborate astrophotography rig that allows him to take clean, long-exposure photographs.
Stoots will observe the upcoming eclipse from his backyard with a camera, telephoto lens and another homemade mount, though not everyone needs to go through the trouble.
First, the most important thing is safety, Stoots said.
People who view the eclipse without specific eyewear can endure solar retinopathy, where the front of the eye focuses UV radiation from the sun onto the retina. Sensitive rods and cones are literally cooked.
Pain is usually not immediate, but eyes can become sore and swollen 12 to 24 hours later. High-definition vision and colors can become distorted. Recovery can take six to 12 months, though permanent eye damage occurs to about half of people affected, Stoots said.
“Sometimes after eclipses, patients show up with actual crescents burned into the eye,” he said.
According to the Vision Eye Institute, there have been several mass incidents of solar retinopathy, including after a 1999 solar eclipse in England.
To avoid eye damage, viewers should wear eclipse glasses that are ISO 12312-2-certified. They also should avoid using standard binoculars or telescopes, which will focus the sun’s rays and amplify damage.
Cameras need protection too.
“The lens is actually collecting light and concentrating it into the camera’s chip, so there’s a good chance you can damage your chip if you leave it pointed at the sun for too long,” Stoots said.
Photographers should buy a solar filter, which blocks more than 99 percent of light. Filters also can be secured over binocular and telescope lenses.
There is a procedure for using the filter. It should be removed right before totality, then replaced when the sun begins to peek from behind the moon again.
During totality, flashes of sunlight will still slip past the moon. “Bailey beads” will shoot in unpredictable patterns through the moon’s craters, and the sun’s corona will be visible.
The extreme contrast between light and dark means multiple pictures with different exposure settings should be taken using a static camera on a tripod, Stoots said. “Bracketed” images can be processed during postproduction to compose a single, well-exposed image.
“At various periods of time, think about what you’ll do and the settings you’ll use. If you try to do it in the moment without practice you’ll get confused,” Stoots said.
Stoots will photograph the eclipse with an expensive 450mm lens. And because the earth’s rotation makes celestial objects appear oblong over long exposures, Stoots will use a homemade mount that slightly rotates the camera to compensate.
Still, specialized equipment isn’t obligatory to photograph the eclipse, he said.
Photographers can take wide-angle photos that include their surroundings.
“You don’t need a mount or a tripod. You can take a picture of the partial or total eclipse with an interesting background, including trees or people,” Stoots said.
Or, viewers can put down the camera and focus on the event itself. Stoot’s astrophotographer friends are split on the matter.
“Some say ‘I have to try to take pictures.’ Others say ‘I want to experience it. I just want to look up,’” Stoots said. “Weird things go on. Temperatures drop; animals may act strangely; birds may stop singing. Look at the people around you, you may see some strange behavior from them too.”
Reporter Kevin Trevellyan can be reached at 208-542-6762.