Re: Re: [APML] Achromats?

[lkt <tan@cox.net>]

I recall seeing an old issue of S&T reviewing the various filters offered by Lumicon, Orion and Meade. I also remember seeing the filter shapes on this review. 

Loke



> 
> From: "Jim Janusz" <jjanusz@dc.rr.com>
> Date: 2002/07/08 Mon PM 03:51:37 EDT
> To: <astro-photo@seds.org>
> Subject: Re: [APML] Achromats?
> 
> Does anyone know the bandwidth of the Lumicon h-alpha filters?
> 
> Just curious.
> 
> Jim
> 
> 
> snip 
> > One good use for an achromat is for h-alpha imaging. The Custom
> > Scientific h-alpha filters are 3-4nm in width and so the color within
> > this range has pretty much the same focus. 3-4nm is much narrower than
> > say a red tricolor filter which might be a 100nm wide. 
> snip
> 
> 
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