Re: Re: [APML] Achromats?

["Jim Janusz" <jjanusz@dc.rr.com>]

Steve, you jogged my memory.  My old notes indicate a 60nm bandpass from 640
to 700nm amazingly wide compared to the CS filters if I'm correct.  Still
not too bad considering the cost.

That compares with the 29 red at 610nm and 25 red at 590nm.

Can anyone confirm that sky glow is at 630nm as Lumicon once noted?

Jim

----- Original Message -----
From: "steve banbury" <banburys@sonic.net>
To: <astro-photo@seds.org>
Sent: Monday, July 08, 2002 1:30 PM
Subject: Re: Re: [APML] Achromats?


> I have their catalog at home with plots for transmissibility.
> Will look it up tonight if noone else has one handy.
>
> Steve
>
> At 04:18 PM 7/8/02 -0400, you wrote:
> >
> >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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