On Thu, Jan 01, 2004 at 07:19:31AM -0500, Herb Chong wrote:
> did you make it yourself or is it designed for photographic use? i know B+W
> makes a 20 stop filter, but i don't know if that alone makes it useful for
> solar work.
I think a 20 stop filter would be dangerous to use for solar photgraphy.
It might block 20 stops of visible light, but let through enough other
wavelengths to fry your eye through the viewfinder. Even if you can't see
the sun at all.
I would strongly discourage anyone from using any filter for solar
photography unless the filter is explicitly designed as a *solar* filter,
not just a very dark filter.
As to the original question on solar filters without colour casts:
I once was given a piece of solar filter that looked just like very thin
aluminium foil. It was a sheet of metal manufactured so thin that it
became transparent enough for solar viewing. The image through this was
noticably whiter than through another Mylar (?) filter, whose image was
more muddy and yellow.
Unfortunately, I do not remember the make. I suggest you ask at a place
that sells telescopes.
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