In my August Reporter
article on viewing the August 21 solar eclipse and again in a blog post, I quoted
information I had read that dark glasses for
viewing the eclipse of the sun should be safe if they were CE-ISO
certified with an "ISO 12312-2" or an "ISO 12312-2:2015" marking. NOT
NECESSARILY SO, now says Amazon.com.
I ordered sets of eight, five and four such pairs of glasses for
relatives and friends, and now, one by one, Amazon has sent me warnings to not use them. This applies to looking
at the sun at ANY time. The glasses I ordered were manufactured by different
companies but ordered from Amazon, and all had BOTH of the above certifications.
Amazon is giving me a credit for these purchases and says I do not need to
return the merchandise.
This is a bummer for those wanting a convenient way to watch
the partial eclipse, but there are other ways one can safely view it. One is
the "pinhole" method described in my article (just do it right).
Another is using a fully developed film negative to look through, but you need
to know how to do this. There are other methods as well.
I wonder how many millions of these "questionable"
glasses have been sold and how many people are going to be very inconvenienced.
Some have made plans to travel long distances to see "totality."
During the 2+ minutes of totality, they say it is safe to look without eye protection, but ONLY then
and not at all before or after, when
the slightest bit of the sun can be seen. We won't see totality here.
Further information can be obtained from the NASA Eclipse website: Copy and paste into your http box: https://eclipse.gsfc.nasa.gov/ SEhelp/safety.html
ReplyDeleteFrom the NASA bulletin:
1. The safest and most inexpensive of these methods is by projection, in which a pinhole or small opening is used to cast the image of the Sun on a screen placed a half-meter or more beyond the opening. Projected images of the Sun may even be seen on the ground in the small openings created by interlacing fingers, or in the dappled sunlight beneath a leafy tree.
2. One of the most widely available filters for safe solar viewing is a number 14 welder's glass, available through welding supply outlets. [Be sure it is No. 14.]
3. Experienced amateur and professional astronomers may also use one or two layers of completely exposed and fully developed black-and-white film, provided the film contains a silver emulsion. Since all developed color films lack silver, they are always unsafe for use in solar viewing.
4. Damage to the eyes comes predominantly from invisible infrared wavelengths. The fact that the Sun appears dark in a filter or that you feel no discomfort does not guarantee that your eyes are safe.