Here's some important advice you've probably heard before: During Monday's solar eclipse, do not fry your eyeballs.
It can happen. Serious eye damage.
But along with learning safe practices, you probably should unlearn a few myths and misconceptions.
First and foremost, there are no special "evil rays" coming from the sun during an eclipse. In fact, an eclipse emits nothing unusual at all.
"The sun is not more dangerous during the eclipse," said Seth Jarvis, director of the Clark Planetarium. "It's just that during the eclipse, people are tempted to look at the sun."
The truth is the sun for the past few billion years has been continuously emitting ultraviolet and infrared rays. You do not want to look into those rays.
"That will literally burn your optic nerve and the retina at the back of the eye," Jarvis said.
To protect your eyes from blindness, Jarvis has a couple of safety devices to recommend, starting with cardboard glasses you can get for a dollar or two.
"These are designed to protect your eyes so that you can look safely at the sun without damaging them," Jarvis said as he slapped on a pair of eclipse glasses. "You can't see anything else, though, other than the sun."
Mike Taylor of Eastern Idaho Public Health said consumers should check the labeling to be sure a pair of eclipse glasses is up to snuff.
"Just make sure that it's certified ISO," Taylor said. "That means it will be safe to view the eclipse through that eyewear."
There have been concerns in recent days about counterfeit or defective eclipse glasses, some with ISO labeling. Amazon issued a recall, and Moran Eye Center followed suit.
Best advice: Buy from a reputable seller, and check for reliability online. NASA and other organizations have lists of approved brands.
There are also advanced options like Jarvis' favorite: welder's glass. But they're only safe if sold as No. 14 welder's glass. Other densities are not dark enough to protect the eyes.
Demonstrating the technique for peering through welder's glass, Jarvis said they are more comfortable than cardboard eclipse glasses.
"These are like $10," he said. "You can pick them up at welder's stores, but we have them here at the planetarium also."
Jarvis warns eclipse enthusiasts not to fall for other safety myths and misconceptions. Don't use sunglasses or smoked glass. Do not look at the sun through an old CD, a DVD or a beer bottle.
"They don't filter out the infrared," he said. "They don't filter out the UV and, honestly, they're not dark enough."
The eclipse can also be safely observed by projecting it onto a viewing surface, something that can be easily done by punching a pinhole in a piece of cardboard.
For those lucky enough to be in the right place — the zone where a total eclipse can be seen — viewers can take the safety glasses off as soon as the totality phase begins. They can enjoy those magical two minutes only as long as the eclipse remains total "because the moon is completely blocking the light from the sun," said Samuel Singer, executive director of Wyoming Stargazing.
"The only thing you're going to see then is what everybody wants to see, which is the sun's outer atmosphere, the solar corona, the crown of the sun," Singer said.
"You have about two minutes," Jarvis said. "And then as soon as the sun peeks out again, back (on) go the glasses."
That brief unprotected look is only possible in the 14 states where the eclipse will actually be total.
"The totality is up north in Idaho and Wyoming," Jarvis said. "Here on the Wasatch Front, we're only going to see only about 91 percent of the sun covered by the moon. And even that little 9 percent left over is enough to hurt your eyes."
Safety glasses shoot down the biggest eclipse myth of all. A belief persisted for thousands of years that an eclipse is something to fear. It's actually a wonder to behold, if you do it right.
"Get the protection," Jarvis said, "and then enjoy the eclipse."