Re: [ATM] SUN FILTERS

["Andreas Derwahl" <andreas@duda-derwahl.de>]

Kia Ora Malcolm,

I am not sure if it's any use to you, but a very detailed and informative
webpage is: http://www.sonnen-filter.de/ , the downside being it's in
German.

Peter Hobel has measured transmission spectra of almost every filter used
for sun observation (including the survival blanket and why it's not a good
idea to use it as sun filter).

Most german amateurs use Baader Astro Solar filter screen which looks very
similar to survival blanket, but the thickness is a lot more uniform and the
coating is on both sides, giving much better optical performance and most
importantly real eye safety. Check out their webpage at
http://www.baader-planetarium.de/zubehoer/zubsonne/astrsolar.htm#asolar,
they might ship to NZ. Not sure if ordering is too much of a hassle, though.

Hope this helps.

Andreas

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