Eye protection while watching a total solar eclipse

[FactChecker]

Here is a video from B&H Photo Video about photographing the total eclipse. It's not clear to me if it is only for the minute or two of totality.

 

[Sagittarius A-Star]

A danger is, if the moon blocks only 99.9 % of the sun, that the eyes can be destroyed for the rest of your live without proper filter, as the video states.

• In such a situation, the sharp borderline between moon and sun triggers, that the eyes auto-focus to infinity, which destroys the retina in the eye.
• Also the eyes widen and let more light in while an eclipse, because the overall luminous flux is small. But the luminous flux per unit area is the danger in this case.

That's even more dangerous than looking into the normal sun without eclipse. But also this can destroy the eyes.

I choose the safe way and look never directly into the sun or other light sources. Also, I don't trust "ISO-certified" filters. Who knows.

 

[FactChecker]

Also, I don't trust "ISO-certified" filters. Who knows.

Get the glasses from a trusted supplier on this list.

 

[Sagittarius A-Star]

Get the glasses from a trusted supplier on this list.

That may reduce the risk.

Unfortunately, you can't check whether a filter meets the ISO standard yourself — doing so requires a specialized and expensive piece of laboratory equipment called a spectrophotometer that shines intense UV, visible, and IR light through the filter and measures how much gets through at each wavelength. Solar filter manufacturers send their products to specialized labs that are accredited to perform the tests necessary to verify compliance with the ISO 12312-2 safety specifications. Once they have the paperwork that documents their products as ISO-compliant, they can legitimately claim to meet the standard on their products and packaging.

Even more unfortunately, unscrupulous vendors can grab the ISO logo off the internet and put it on their products and packaging even if their eclipse glasses or viewers haven't been properly tested. This means that just seeing the ISO logo or a label claiming ISO 12312-2 compliance isn't good enough. You need to know that the product comes from a reputable manufacturer or one of their authorized dealers.

Source:
https://eclipse.aas.org/eye-safety/iso-certification

 

[Andy Resnick]

But that is the problem. Totality ends so fast and suddenly that with binoculars you'd have eye damage before you can blink.

That is empirically not true, as I can attest. Furthermore, using a stopwatch to measure elapsed time is an additional safety check.

 

[FactChecker]

That is empirically not true, as I can attest.

We should be careful here. This thread has mixed discussions of viewing with the naked eye, binoculars, and telescopes. There can be orders of magnitude difference in the amount of light gathered by these.

Furthermore, using a stopwatch to measure elapsed time is an additional safety check.

But the exact time varies quite a bit with the distance from the center path of totality. I would not count on knowing the time without accounting for that.

I would not give advice in this forum that could easily lead to permanent eye damage.

 

[Vanadium 50]

Apart from not knowing the exact duration in the place you will be standing, and not knowing exactly when totality starts, do you really think people will be looking at the stopwatch instead of the sky?

 

[Vanadium 50]

I have a problem with the advice "I did something risky and got away with it. You can too," (Not just for an eclipse)

Further, if something is 99.9% safe, that works out to thousands with eye damage.

I lost my vision (for a different reason), and after a year, I have not fully recovered, I would not wish this on anybody. I think the "how far can we push the envelope" discussions are dangerous, and misguided, and the consequences of miscalculating are sufficiently severe that we should not go down this path. Especially on a public forum.

 

[Stavros Kiri]

There's also this safe idea:
https://www.physicsforums.com/threa...nnular-apr-08-2024-total.1051127/post-7070075

 

[Orodruin]

Found this randomly:

Put protection on when the outro starts …

It is in jest obviously, but if you are going to view the totality with the naked eye - make damn sure you know how long totality will last at your location and that you start a timer that will go off well before totality ends so you have ample time to look away and/or put protection back on.

 

[berkeman]

Rhut-rho...

https://www.cnn.com/2024/03/29/world/fake-real-glasses-solar-eclipse-wellness-scn/index.html

Counterfeit eclipse glasses with black lenses that have straight left and right edges from China (top) are printed with text copied from real eclipse glasses, but the counterfeit glasses are missing the company address. Meanwhile, real eclipse glasses from American Paper Optics (bottom) have reflective lenses with curved left and right edges.
American Astronomical Society

“Until recently, the only counterfeit products we knew of were cardboard-frame eclipse glasses made by an unidentified factory in China but printed with ‘Mfg. by: American Paper Optics’ (APO) on them,” the AAS shared in a news release. “APO is one of the major U.S. manufacturers of safe solar viewers and prints its name and address on its eclipse glasses, whereas the Chinese copycat products have APO’s name but not its address. Thankfully, these particular counterfeits appear to be safe.”

 

[Vanadium 50]

Counterfeit products from China? Who'd have thunk it?

The US should get even. Send them some 737's.