Re: [APML] Bill Fletcher's Tri-color work(was 23a filter)

[Chuck Vaughn <aa6g@aa6g.org>]

Ulrich,
 
> If I didn't want to have custom-made filters or try finding exotic stuff,
> then the filters I'm to use are 25A, 47 and 58 - are these the filters
> usually used in black&white terrestrial photography to enhance contrast? If
> so, those wouldn't be too hard to get....

I explain the problem with using those filters for astrohphotography in the
"Color Photography of Emission Line Objects" article. This should answer
most of your questions.

Chuck

http://www.aa6g.org/Astronomy/articles.html

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