Re: [APML] IDAS LPS filter & Provia 400F

["Alson Wong" <alsonwong@earthlink.net>]

The filter factor depends on the object. I don't have any hard numbers, but
I'd say that for emission nebulae, the filter factor is close to 1, and for
sky fog, around 3.
--
Alson Wong
Riverside Astronomical Society
  http://www.rivastro.org/
Visit my Web site at <http://home.earthlink.net/~alsonwong/index.htm>


----- Original Message -----
From: "Chris & Jennifer Cook" <ccjd@ix.netcom.com>
To: <astro-photo@seds.org>
Sent: Tuesday, July 09, 2002 10:18 PM
Subject: [APML] IDAS LPS filter & Provia 400F


> Hi all -
>
> Has anyone tried this combination?
> Also, for those of you that use the IDAS LPS filter, what is the filter
> factor?  I'll be shooting at f/6.9.
>
> Chris
>
>
> ==================
> Chris Cook
> Astronomical Photography
> www.abmedia.com/astro
>
>
>
> --  APML Archives at <http://astro.umsystem.edu/apml/>  ---
>              Unsubscribe at <majordomo@seds.org>
>



--  APML Archives at <http://astro.umsystem.edu/apml/>  ---
             Unsubscribe at <majordomo@seds.org>