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A solar eclipse begs to be seen, but only at the expense of your eyes—looking at one in the wrong way can do long term damage to your vision. It’s ironic (if only completely necessary) that we hype these phenomena as visual spectacles that we must also resist looking at with our naked eyes.
As the Ring of Fire annular eclipse nears later this month, promising to light up the fringes of the moon with the sun’s burning glare, it’s important to know that you can technically look at the eclipse—you just need the right tools and knowhow to do it without risking your eyeballs.
How looking at an eclipse can damage your eyes
This isn’t an old suburban myth like the one about the dangers of swimming unless you’ve waited exactly 30 minutes after eating, but a verifiable medical advisory: You definitely shouldn’t look at an eclipse with your bare eyes. As Dr. Ralph Chou explained for NASA in 1997, looking directly at the sun during an eclipse can cause “‘eclipse blindness’ or retinal burns.”
Chou described just how and why the overwhelming light generated by an eclipse is very bad for your eyes:
Exposure of the retina to intense visible light causes damage to its light-sensitive rod and cone cells. The light triggers a series of complex chemical reactions within the cells which damages their ability to respond to a visual stimulus, and in extreme cases, can destroy them
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The severity of this damage will vary depending upon the length of exposure. It’s entirely possible, god forbid, that you will completely lose your vision from staring directly at an eclipse. This is why, in Chou’s view, “It is never safe to look at a partial or annular eclipse, or the partial phases of a total solar eclipse, without the proper equipment and techniques.” Listen to the medical professionals, folks (and maybe not the disgraced former presidents).
How to safely watch a solar eclipse
The first thing to remember is that regular sunglasses will not protect you from the harmful effects of looking at an eclipse, regardless of how dark they are. This also applies to just staring at the sun when it’s not in an eclipse phase. This giant, ever-burning ball of gas, located 93 million miles away from our planet, has sustained the entirety of all known carbon-based lifeforms for billions of years; it’s not to be trifled with. The only time that it’s largely safe to look at the sun during a solar eclipse is during the phase of “totality,” when the sun is completely blocked by the moon.
Chris Westphal, a photographer who’s captured pictures of more than a few eclipses, tells Lifehacker a bit more about the trickiness of ogling an eclipse at totality:
It is only during a total solar eclipse that it can be okay to look at it, but even then it is highly advisable that you know exactly when totality starts and ends, because if you look at the sun before or after these moments, it can lead to lasting eye damage or even blindness.
Barring the rarity of knowing exactly when totality will take place, you need the proper equipment. Luckily, eclipse glasses are widely available and don’t require much investment, but you need to watch out for counterfeits. One crucial certification to look for is that the glasses are approved by the International Organization for Standardization, which marks certified products with “ISO.”
Per Space.com, here’s what an ISO-approved sunglasses will promise you:
- No more than 0.00032 percent of the sun’s light may be transmitted through the filters.
- The filters must be free of any defects, such as scratches, bubbles, and dents.
- Handheld viewers must be large enough to cover both eyes.
- Labels on the viewers (or packaging) must include the name of the manufacturer, instructions for safe use, and warnings of the dangers of improper use.
There are plenty of companies that manufacture glasses for safely viewing an eclipse. If you’re looking to become something more than a casual viewer, however, Westphal recommends “a white light filter on a telescope or a more technical Hydrogen-Alpha telescope,” the latter of which is used by astronomers to observe the sun’s atmosphere.
Either way, the bottom line is to simultaneously respect the sun and your retinas—which you can do with the right equipment on hand.
from Lifehacker https://ift.tt/3pfqHlJ
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