Like many, we bought solar glasses to view the eclipse, and are now in a strange place where we can't tell if they're safe or not. The big fuss seems to be about ISO 12312-2 compliance. Apparently there are some glasses which are claiming to be certified and putting the logo in the glasses when they are, in fact, not up to spec.

Now the only "solution" that has been given is to buy from one of the "reputable" vendors documented by the AAS. Many smaller vendors are crying foul, saying the big guys are just trying to push out competition.

So my question is this: if I had a pair of glasses, what would be the proper way of determining if they met ISO 12312-2 standards? Is there supposed to be a way for a customer to trace their purchase back and verify that the company that made them at least has their paperwork in order? (A company that has their paperwork and is still counterfeiting anyway is a different challenge).

Obviously the astronomy community is interested in ensuring their products are safe. How were they supposed to do that in the ideal circumstances? If I can't confirm their certification as a small-time buyer, how would a large-scale buyer of, say, 100,000 glasses or viewers determine that the product they are buying is genuine before someone burns their eyeballs? Surely when there are hundreds of thousands of dollars on the line, there would be a process to demonstrate compliance.

EDIT: I am specifically looking for how one is supposed to verify these glasses without relying on a whitelist provided by a single group such as the AAS (other than perhaps the ISO community itself). Surely there is a way to verify claims of ISO compliance without relying on the good intentions of a professional society. Otherwise, what is the point of having certifications in the first place?

  • 1
    $\begingroup$ Possible duplicate of How to test direct sun viewing glasses $\endgroup$ Commented Aug 13, 2017 at 23:14
  • $\begingroup$ @pacoverflow I added an edit. I'm looking for the process that would be in place if you didn't have a society like the AAS creating their own whitelist of companies. Surely there is a solution for problems like this when you don't have the AAS trying to step in and solve it. $\endgroup$
    – Cort Ammon
    Commented Aug 14, 2017 at 1:09
  • $\begingroup$ I'm also not looking to test them. I'm looking for a way that someone with the proper equipment has done the testing. $\endgroup$
    – Cort Ammon
    Commented Aug 14, 2017 at 2:10
  • $\begingroup$ You might be out of luck on this. Testing it yourself is going to require equipment you likely don't have just lying around (but could probably buy if you're up for fronting the cost) and I doubt anyone out there is systematically testing every pair of glasses from every vendor to ensure they actually meet the standards like they say they do. $\endgroup$
    – zephyr
    Commented Aug 14, 2017 at 12:52
  • $\begingroup$ @zephyr I don't expect systematic testing. But it does seem like if I was a supplier that was undergoing proper testing of my products (testing samples, of course), there would be some meaningful way for me to advertise that I underwent this testing in a verifiable way (such as "here's the lab that gave me this certificate. Go call them and confirm that they actually issued me this certificate."). I'm finding it hard to believe that there's no way to follow a chain of certifications, but it indeed seems impossible to follow. $\endgroup$
    – Cort Ammon
    Commented Aug 14, 2017 at 14:23

1 Answer 1


if I had a pair of glasses, what would be the proper way of determining if they met ISO 12312-2 standards?

The process involves a lot of lab equipment, calibrated sources of infrared, visible light, and ultraviolet, and calibrated detectors. Extremely unlikely you'll be able to whip something up in your garage.

Buy from vendors with good reputation; these are online stores that sell nothing but astronomy equipment, and they know what they're dealing with. If you're an astronomer, you know who those are. If you aren't, go on various astronomy forums and see which vendors people are recommending. Or see the AAS page for a list of vendors.

Amazon is now cracking down on bad eclipse glasses, but realistically speaking they are not an online store specializing in astronomy, so their product vetting may or may not be perfect.

It's getting a little late now, so better hurry up and get your eclipse glasses already.

You can always dash to the local welding supplies store and get a #14 welding glass. It's completely safe and passes the ISO standard. Maybe get the whole mask to go with it, so your face won't get sunburned.


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