Michael Bakich
Oh, it's absolutely crucial. The partial phases of an eclipse are essentially as strong as looking at the Sun when there's no eclipse going on. So you need approved solar glasses. And Ralph Chou is the one who set the standard, and that's the standard that must be on the glasses - so, eclipse glasses from American Paper Optics, or Rainbow Symphony, or Thousand Oaks Optical - those are the three that carry the approval certificate number right on the glasses. And those are the three that I would recommend.
Kelly Beatty
Invariably, people come and they are NOT prepared. I don't know, maybe they think the tour group is gonna hold their hand through the whole thing. In any case, one of the things that's really useful to have during an eclipse is filters for your camera, your binoculars, that you can view the partial phases of the eclipse up to and after totality. Well, we announced that we would be ready to make filters for people if they didn't have filters - of course, we had told people to get filters ahead of time, but - who read all that information? And Dan, as you know, in the couple of days leading up to the eclipse, we had long lines of people waiting to have filters made for their equipment, and it took you and me, we were cranking out filters as fast as we possibly can. And I think I brought, like, a square meter of eclipse filter material, and it got to the end and we were like, figuring out where the scraps were that would be big enough to fit this particular lens or this particular pair of binoculars. And it was pretty comical, and we went through a lot of filter material that day, putting filters together.
Yes, Kelly - that's a great memory for me - that you would put forth that effort for all the people who had come on your tour! It says a lot for the product that you - as a representative of Sky & Telescope - delivered!
Let's now talk to our eye safety experts - Dr. Ralph Chou, who wrote the ISO standards for safe solar viewing filter material, and Mark Margolis who implements those standards in all the glasses his company [Rainbow Symphony] produces!
Ralph Chou
It is so important to make sure nobody gets hurt.
Ralph Chou
And that's why it's so important to have the safety message out there, to make sure people know when it's safe to actually use the proper protection.
Ralph Chou
The problem is that there's so much misinformation out there, especially on the Internet. A lot of the time, people are very well intentioned, but they edit things because they need to keep space down. But [when] they do that, they tend to lose vital parts of the safety message. You know, this is really the big problem, because there's a lot of misunderstanding about when it's safe and when it's not safe to look at the eclipsed Sun, and also a lot of misunderstanding about where it is unsafe to look at.
Ralph Chou
The important thing is that people need to make sure that they're getting the information from good, reliable sources - that the information is not being chopped up and made unusable by an indiscriminant editor. That is bound to happen - we just know it does, because it's happened at every eclipse that I've been involved with the publicity for since the early 70s. And it is a constant problem. It's really not the editor's fault, because they just don't understand - they haven't got the background.
Ralph Chou
Unfortunately, when you have editors who don't understand the science, and need to chop the space in two to accommodate everything else, the message gets lost in the cutting-room floor.
Ralph Chou
It's every bit as dangerous to look at a partial eclipse as [it is] when the Sun isn't in eclipse at all.
Ralph Chou
If you were to take a look at the retina that has been exposed to [a] very very high level of sunlight, the first damage that you notice is a disruption of the parts of the light-sensitive cells - the rods and cones - where the light is turned into a visual signal. We call them rods and cones because of the shape of the photo-sensitive parts of those light receptors in the human retina. In a very very high-magnification image of those cells, what you see is that those light-sensitive parts of the light receptors contain stacks of photo pigment. And the actual damage that's done by short-wavelength light is to disrupt those pigment disks. It totally disrupts them, and that's why you lose vision - because the parts of those cells that would take the light and convert it into an electrical signal that travels through the optic nerve to the brain is basically disrupted.
Ralph Chou
That's exactly what it is - it's an overloading of those pigment disks. Now if the damage is not too severe, those pigment disks can be regenerated - but it takes a lot of time. And so, if the light receptor has not been lethally injured in the process of being overloaded by the sunlight, it will eventually reconstruct its pigment disks, and start functioning again. So the result is that if you're lucky enough to have that happen, your vision will eventually recover. There's a small group of people, unfortunately, who for one reason or another will end up with that type of damage being irreversible; what happens in those cases is that the photoreceptors are destroyed.
Ralph Chou
Actually, you know, it's interesting, because if we were talking sunglass exposure, I'd be talking about Ultraviolet. But in the case of looking at a solar eclipse, the problem really isn't Ultraviolet radiation per se. It really centers around the blue part of the visible spectrum, which causes something we call retinal phototoxicity.
Ralph Chou
That tends to happen if they've looked for a long time without protection, or if they've used an unprotected or unfiltered piece of optical equipment to look at the Sun.
Ralph Chou
We're very fortunate that, in fact, that kind of eclipse injury is extremely rare.
Ralph Chou
One of the earliest papers I ever wrote was on the demographics of solar eclipse eye injuries. This was based on a survey we did of Canadian eye injuries following the February 1979 eclipse. And it was basically seen in partial phases through most of the US and Canada, and there was just that narrow band of totality as well, across the US and Canada. We got some really interesting demographics out of that, about who gets hurt. And it's mainly young males, adults, of age from about 15 to 30. When we asked the question about whether these folks had heard the warnings, or read anything about how to view the eclipse, almost all of them said that they were aware that there had some kind of announcement - [that] they chose to ignore.
Ralph Chou
That's right, you know - they were curious, but they figured the warnings didn't apply to them.
Ralph Chou
Yeah, you know the fact is that it's pretty hard to really hurt your eyes when you look at a solar eclipse, but unfortunately every time we do have a total eclipse of the Sun, or even a partial eclipse of the Sun, somebody does get hurt - despite our best intentions of providing information.
Ralph Chou
You end up with a very very focused part of the retina that is essentially blinded by the damage to these cells.
Ralph Chou
[In] one or two cases that I've seen over the years, you can almost tell from the shape of the scar that's left in the back of the eye, when they actually looked at the sun. Burned right in...
Ralph Chou
Yeah!
Ralph Chou
Yeah. It's entirely preventable. And that's the sad part about it.
Jay Pasachoff
We've had examples in both the United States and Australia, where kids have been locked in basements, on the side of the school building away from the Sun, lest they go blind.
Ralph Chou
That one actually happened in Western Australia, around Perth, with the 2005 solar eclipse. That was a real black eye, because the Western Australian government in fact ignored all of the expert opinion. We were much more fortunate that the folks in Queensland listened to the local astronomical experts, and they brought me in to help out with that effort. And we managed to get some official sanction for the solar eclipse glasses products, and got the certifications in place. A lot of the eclipse path was, in fact, clear - so people did see it quite happily.
Michael Bakich
[it's] very, very easy to safely protect anybody who's going to be viewing the eclipse.
Ralph Chou
The thing is that you can get welding filters from a lot of places. They're very inexpensive, but you've gotta make sure that you use at least a shade #12, and preferably a shade 14, in order to really have enough radiation protection for the eyes.
[ed: Please make sure that if you do this, do NOT use the "instant-darkening" kind of welder's glass - they don't get dark enough, fast enough!]Ralph Chou
The solar eclipse glasses - the dark plastic or aluminized polyester type solar eclipse glasses, are probably the best bet, because unlike a lot of welding filters which are made out of heat-hardened glass, if you drop the solar eclipse glasses, onto a concrete or other hard surface, they don't break - which is one thing that happens with welding filters.
Ralph Chou
You know, we're really trying to steer people away from welding filters if at all possible, [and] to use the eclipse glasses.
Michael Bakich
[Those] glasses are really cheap...
Ralph Chou
They look like sunglasses.
Ralph Chou
The European Union produced a special standard a number of years ago, which covered sunglasses as well as what they called, filters for direct observation of the Sun. And many countries have signed onto the idea that regional standards like the EN standard should be replaced by ISO standards - which are worldwide in scope. For the last, almost a decade, I've been involved with a variety of ISO standards being developed, and one of them happens to be a specific standard for the solar filter technology that will replace the EN standard eventually. it's [as of 2014] in its final stages of production - in fact, we're hoping that the next committee meeting which happens in June [2014] in London, England, will see the final approval of that standard. Which means it'll be out in time to be enforced for the manufacture of filters for the 2017 eclipse, over the USA. [ed: As of 2017, the ISO standard has been adopted worldwide, and has replaced the EN standard that Dr. Chou spoke of in this interview. All of Rainbow Symphony's glasses meet this new ISO standard.]
Ralph Chou
Pretty much every one of the major solar filter manufacturers has sent their stuff through my lab for assessment over the years.
Ralph Chou
I worked with some of the people who really started with the manufacturing of these products, going back to the late 70s.
Ralph Chou
Yes. Mark and I go back a long, long way - I think from when he first started to sell the glasses.
Glenn Schneider
Mark, of course, does a great service by providing his eclipse glasses - they're a great product, they're very inexpensive, and he's made them available in huge quantities all over the globe for people. They're safe, they're easy to use - and of course, that's for the partial phases of the eclipse - not for totality. But for people who haven't seen an eclipse before, they're essential to the run-up for the big show. Mark has done yeoman's service for providing those for people.
OK - That's a great introduction! Let's right now go over to Mark Margolis of Rainbow Symphony - the manufacturer of these eclipse glasses!
Mark Margolis
I mean, there's not a lot of things you can do in your life, you know what I mean, that make a difference? This is one of the things that we can do, right? It's one of our areas of interest, and, yeah - it's something we can do, so… we do it! It's a heck of a lot of fun, Dan, I gotta tell ya!
Mark Margolis
Since '91, and before that - yeah! We've literally been involved in every eclipse in one way or another - whether it's an annular, a partial, or a total - somewhere in the world, since 1990!
Mark Margolis
What's interesting is, we really have been instrumental in people being able to do this safely.
Mark Margolis
We're talking about safety, we're talking about people's eyes.
Mark Margolis
We take this seriously, and at the same time have a lot of fun with what's going on.
Completely agreed - you've done a great job, Mark!
Ralph Chou
The product that he has been selling has been certified as meeting the EN standard requirements, and in fact I sort of hooked him up with the standards certification laboratory that did that certification work.
Mark Margolis
For years, he's been so helpful with a lot of things that we need to do relative to the safety of Solar Viewers. And, between their facility up in Canada - the University of Waterloo - and another facility down in Australia, these guys have pretty much written the book on the safety of solar viewing.
Mark Margolis
The first certifications that were issued were the CE standard, and that came about in [circa] 1994, and we had to have the CE certification to import into Europe for the 1999 total solar eclipse. So that certification met the transmission requirements of 12-16 EN169/1992.
Mark Margolis
Since then, there have been additional standards like for instance - we call it the "Queensland Directive" - and that was really spearheaded by Terry Cuttle down in Australia. And that was the AS/NZS standard [1338.1:1992] that we had to have, to import into Australia.
Mark Margolis
Then, the follow-up to that is the ISO standard - and there is an ISO number - that ISO number is 12312-2:2015. And, just as a point of information: From all the way back, from the CE forward, as far as the certifications and the standards, a lot of this has been spearheaded by Ralph Chou out of Waterloo University in Canada. He has been absolutely instrumental in finally getting to the ISO standard, or an international standard for eclipse viewers. He really deserves all the credit for getting us here, creating the standard, and making sure that all our materials, glasses, viewers, and filters can meet that standard.
Mark Margolis
It's one of the most fun parts of our business - working with the glasses, solar eclipses, and - and with people like you!
Mark Margolis
It's - it's been great, man!
Ralph Chou
It's so important, because people don't realize how dark these things are. The eclipse filters are just as dark as a shade 14 welder's filter, which means you're only getting 1 part in 250,000 of the light coming through. [It's] perfectly OK to look at the Sun, and see the disk being covered up, but it is far too dark to be able to see anything around you on the surface of the Earth.
Ralph Chou
Because these filters are so dense, you can't walk around. You can't operate a motor vehicle with them.
OK, I see that that's important! - so everyone - PLEASE do NOT walk, or drive any vehicle while you have the glasses on!!
Ralph Chou
You can do that if your neck and back will allow you. You know, a lot of the time, the Sun is so high up that you can't really look at it for more than about ten seconds before something starts to hurt. It actually becomes painful to hold yourself in place, to cock your head back and look at the Sun that way. You know, I know people who have actually looked at the eclipse with the glasses for lengthy periods of time; they've not suffered any damage. But most of the time, they were lying down somehow, so that they didn't have to put their necks back in that awkward position.
Jay Pasachoff
Though for the partial phases you have to look through a filter, you have to be sure that during totality you put that filter away.
Ralph Chou
[As] soon as that's all covered up - so if you're watching the eclipse, you've got the crescent getting smaller and smaller and smaller, and at some point [you] can't see anything any more - that's the beginning of total eclipse. Take the glasses off at that point and look at the corona surrounding the Moon. And, it's perfectly safe to look at that without using any kind of eye protector - in fact, if you tried to use the filters you'd see nothing.
Ralph Chou
Absolutely - because there isn't enough light coming from the sky, from the surrounding corona, to do any damage. The dangerous thing is the uncovered parts of the disk of the Sun.
Jay Pasachoff
Yes. It's safe to look at the eclipse during totality.
Jay Anderson
We're so caught up in eclipses that we don't realize that you actually have to tell people to take them off during totality. We sort of, "Oh, it's obvious you take it off." Well, you know something? It isn't obvious that you take them off during totality.
Ralph Chou
The problem is always, when is it really safe to look at a diamond ring effect? Because, what it is, is the last bits of the glowing disk of the Sun. The light from those parts of the solar disk, streaming through the valleys on the edge of the Moon - and having those isolated bursts of bright light. And it's really tough to say when it's really, really safe to do that. If one really wants to be safe about it, you keep looking at the partially-eclipsed sun through the filters until you can't see anything any more - which really is the end of the diamond ring effect. And then you take the glasses away, and you can see the corona glowing in the sky, and look at that as long as the [totally] eclipsed Sun is visible. But, the first inkling of a bright bead of light on the edge of the sun again, you gotta put the filters back on.
OK - we'll end our discussion on that advice.
Kelly Beatty
For people who might be listening to this, get your filters ahead of time, before you go out ready for the eclipse. And then, it'll be much calmer for you, and for whomever you might be with.
Agreed! And on eclipse day, we all need a little bit less drama! OK, now let's move on to another topic - Why on Earth do people choose to travel the globe chasing eclipses? (This should be interesting!)