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

[Chuck Vaughn <aa6g@aa6g.org>]

Philip,
> 
> Firstly you have to obtain a set of
> filters with the correct spectral response.  Then you have to calculate
> exactly how long each exposure needs to be, dependent on the spectral
> response and the transmission of the filter.

Fortunately this is not as hard as it was a couple of years ago. Custom
Scientific is selling a set that looks good and I saw a set made by True
Technology in the UK that looked good too.

http://www.users.dircon.co.uk/~truetech/ccds.html

Here's another set from Germany that wasn't too bad except that the blue
filter has a nasty little spike at 656nm which would end up recording
H-a in the blue channel. :-(

http://www.astro-shop.com/Top/Filter.html

Chuck <aa6g@aa6g.org>

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