Re: [APML] 35 mm Camera & Focuser

[George Anderson <georgea@cam.org>]

Hi Serge

I doubt if you could "butcher" an OAG enough to make a difference. You
would have to chop a fair bit out of the body. And even if you could cut
that much out of the body length, the prism would definately infringe on
your photographing area and cause all sorts of grief.
Your only option (short of modifying the OTA) may be to see if
everything is stiff enough, and solid enough to use a guidescope.

George Anderson
Montreal Canada

Clear skies and good health

Serge Theberge wrote:
> 
> John/Bill/George,
> 
> Could the Vixen or Lumicon OAG be tweaked somehow instead of changing the
> scope configuration? It would be nice if I could do off-axis guiding with
> this new scope that I still haven't received yet (although they are
> promising that it will arrive by sleigh before the end of December!)
> 
> Serge
> 
> > -----Original Message-----
> > From: astro-photo-bounces@seds.org
> > [mailto:astro-photo-bounces@seds.org] On Behalf Of John C. Mirtle
> > Sent: Monday, December 01, 2003 11:13 PM
> > To: Discussion of Film Astrophotography
> > Subject: Re: [APML] 35 mm Camera & Focuser
> >
> >
> > Bill,
> >     You are absolutely correct - you could do this. However,
> > this would put the secondary and the bottom end of the
> > focuser 1" further up the optical path. Increased vignetting
> > is the result, hard to say how much exactly but at f4 the
> > light cone is pretty steep. It would also be a bit tough to
> > glue everything together. The OD of the flattener is 60mm,
> > the OD of the Lumicon OAG is 50.8mm. Rube Goldberg  would be
> > proud... :-)
> >
> > John Mirtle
> > Calgary, Ab. Canada
> >
> > ----- Original Message -----
> > From: "William R. Mattil" <wrmattil@ix.netcom.com>
> > To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> > Sent: Monday, December 01, 2003 9:25 PM
> > Subject: Re: [APML] 35 mm Camera & Focuser
> >
> >
> > "John C. Mirtle" wrote:
> >
> > >     Not much has really changed then. Herm Perez can
> > probably confirm
> > > this.... As I understand it, there isn't enough back-focus
> > on the R200
> > > to install an OAG. In other words, if you install one, it
> > won't rack
> > > in far enough for the camera to focus.  :- (
> >
> > Wouldn't it be rather trivial to move the mirror forward to
> > restore the focus point and accomodate the OAG ? Before I got
> > a low profile focuser thats what I did on my 253mm f/6. Moved
> > the mirror 1" forward.
> >
> > Regards
> >
> > Bill
> >
> > --
> > William R. Mattil |
> > wrmattil@ix.netcom.com | http://celestial-images.com
> > (972) 399-4106 | _______________________________________________
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