RE: [APML] Tech Pan/Ha filter focusing

["Scott Hammonds" <capella@creatorsview.com>]

Jim, Chris,
Thanks for the reply. I was afraid of this. In my attempt to try
something that might help reduce the affects of light pollution here at
my house I forgot about this discussion from several months ago. My
scope is an f5.4, not nearly as fast as your Schmidt. Nothing like dark
skies!!!

Scott Hammonds

 

-----Original Message-----
From: astro-photo-bounces@seds.org [mailto:astro-photo-bounces@seds.org]
On Behalf Of Jim Janusz
Sent: Wednesday, June 04, 2003 4:57 PM
To: Discussion of Film Astrophotography
Subject: Re: [APML] Tech Pan/Ha filter focusing

Hi Scott,

I would say no.  The Ha filter will shift focus towards the Ir as well
as
the glass thickness.  Focusing for Ha is best done photographically
using
some type of scale on the instrument.  See John Mirtle's page for a
great
article on this.

http://members.shaw.ca/jmirtle/ha.htm?

Sorry.

Jim
----- Original Message ----- 
From: "Scott Hammonds" <capella@creatorsview.com>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Wednesday, June 04, 2003 11:47 AM
Subject: [APML] Tech Pan/Ha filter focusing


> Hey Tech Pan Junkies,
> This question may have been addressed before, forgive me if it has and
> for being too lazy to search the archives.
>
> I assume one day the weather will actually be clear again and I'll be
> able to shoot some film. I just ordered a 48mm Ha filter to use prime
> focus with my 4" scope. Can I use my IDAS filter to focus and then
just
> replace it with the Ha filter and achieve accurate focus?
>
> Any help would be greatly appreciated.
>
> Thanks,
>
> Scott Hammonds
>
>
>
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> Astro-Photo mailing list
> Astro-Photo@seds.org
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>


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