On 2012-05-17, Artemus wrote:

"Existential Angst" wrote in message
...
"mike" wrote in message ...
I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.

[ ... ]

Arc welding puts out lot's of UV. Why wouldn't a helmet already
have UV filters in it?

It does -- and the auto-darkening ones block the UV even when
they aren't dark.

But -- I suspect that the problem with viewing the sun is more a
matter of IR than UV -- something which can boil the back of your
eyeball. Gas welding glasses have good IR blocking. Arc welding hoods
have good UV blocking. Probably you want both at the same time for
viewing an eclipse -- if you don't go with the pinhole camera approach,
which strikes me as the best -- especially since you can have more than
one person viewing the image at once, instead of fighting over the
filters. :-)

Enjoy,
DoN.

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