Here’s what not to do to safely watch the total solar eclipse

We want you to have an excellent eclipse. This requires planning, research, some equipment. A total solar eclipse isn’t the kind of thing where you can just wing it.

The best practices for observing a solar eclipse are really not that complicated, but these events are so rare for most people that it is easy to forget the basics — even after reading the wealth of highly instructive stories we have already published.

In this latest effort, we will be more direct in telling you what not to do Monday.

Do I need to wear eclipse glasses?

You have to wear eclipse glasses at all times when any part of the sun is visible. But there is an exception: Do not wear eclipse glasses during the brief period of “totality,” when the sun’s face is completely blocked by the moon, leaving only the glowing solar corona.

Although the entire Lower 48 will see at least a partial eclipse, most areas will not experience a total eclipse, not even briefly. Everyone outside the path of totality will need to wear eclipse glasses at all times.

During totality, though, you can safely remove your eclipse glasses. If you don’t, you will wonder what the fuss is all about. But totality lasts just a few minutes, so the glasses don’t stay off long. The maximum duration of totality in the United States will be 4 minutes and 27 seconds at the Texas-Mexico border. You need to be prepared to put the eclipse glasses back on as soon as the sun starts to show itself again. Children may need close supervision.

Can I make eclipse glasses at home?

This is a terrible idea, so don’t even try. Eclipse glasses are designed to screen out 99.99 percent of the light, about a thousand times the blockage of standard sunglasses, said Lisa Ostrin, a vision researcher and optometrist at the University of Houston’s College of Optometry.

Some welder’s filters can be employed during an eclipse, but they need to be at the right setting, according to the American Astronomical Society.

There are all kinds of nifty options for observing the effects of the eclipse without looking directly at it. NASA, for example, has suggestions for building a homemade pinhole projector that will allow indirect viewing of the eclipsed sun.

Is it safe to look at the eclipse through a camera?

People take pictures of the total solar eclipse on the Washington Monument grounds in 2017. (John McDonnell/The Washington Post)

It is not safe to look at the partially eclipsed sun through a camera without a specially designed solar filter. The same goes for binoculars or a telescope. Doing so “will instantly cause severe eye injury,” NASA warns.

The exception, again, is during the brief period of totality.

The American Astronomical Society has an additional warning: “Do not look at the Sun through an unfiltered camera, telescope, binoculars, or any other optical device while using your eclipse glasses or handheld solar viewer in front of your eyes — the concentrated solar rays could damage the filter and enter your eyes, causing serious injury.”

Is it okay to glance at the partial eclipse for just a second or two?

Don’t do it. You should avoid looking at the sun even briefly.

The danger is solar retinopathy, or eclipse blindness. Our eyes are not evolved to look directly at the sun, even if it is mostly eclipsed and only a sliver of its usual self, or if the sunlight is dimmed by clouds.

“Any eye-care professional will say it’s not safe even for a second,” Ostrin said. “As soon as that light is focused on your retina, it can begin to damage the cells.”

She added, “During an eclipse, people may not have that natural reaction to look away. We don’t have pain receptors in your retina, so you can’t tell when its starting to damage your retina.”

Can I take a picture of the eclipse with my camera or phone?

Yes, but NASA advises against aiming your camera or phone at the eclipse unless you have a solar filter to protect it in the same way that eclipse glasses protect your eyes. You should also consider using a tripod to reduce motion blur and keep the photo framed the way you want it, so you can avoid having to look toward the sun repeatedly.

Another tip: Don’t try to take a selfie with the partially eclipsed sun over your shoulder, because the ultraviolet radiation can reflect off your screen and damage your eyes.

Can I say the experience is good enough at 99 percent totality?

This is a judgment call, and almost all eclipse aficionados judge the answer to be no.

We recognize that not everyone has the flexibility and resources to get into the path of totality. Some people have day jobs, for example. But to be clear, if the sun is still partly visible, you won’t get the full effect of a total eclipse. Totality is special. Just ask Matt Cappucci, or David Baron, or Bina Venkataraman, or David Von Drehle, or Annie Dillard.

There are maps online showing the path of totality, and the better ones show how many minutes totality will last in any given location along the path. At the very edge of the path of totality, the sun may be fully obscured for only a matter of seconds, while at the center of the path, the sun will be blocked for roughly four minutes. There is no difference in how totality will look, however; only the duration is different.

A final suggestion: Don’t race around like a maniac trying to get in the perfect spot for the immaculate experience. There will be a lot of cars on the road, and some people may have missed the driving tips from AAA. For one, don’t pull over in dangerous spots to witness the eclipse. AAA warns drivers that there could be pedestrians staring at the sky or nocturnal animals emerging onto roadways during totality.

And this AAA dictate seems very wise: “Do not attempt to watch the solar eclipse while driving!”



Joel Achenbach 

Washington Post