Re: [APML] 8" Reflector decent enough for prime focus AP?

["Jim Ives" <flyboy9990@earthlink.net>]

Rex,
    I'm sorry I missed most of this thread. Was it mentioned to consider a
vixen RS200 ? Herm uses one of these and takes great photos! See:
http://www.vixen.co.jp/english/index_e.htm

Jim Ives
----- Original Message -----
From: "Rex Moore" <RMoore@fool.com>
To: <astro-photo@seds.org>
Sent: Tuesday, March 12, 2002 10:29 PM
Subject: RE: [APML] 8" Reflector decent enough for prime focus AP?


> Thank you all so much for your input... extremely helpful (though I am
> disappointed, of course ;)).
>
>
> I'm sort of scratching my head right now because I just can't go over
$600.
> So I may have to buy this Orion anyway. I'll certainly try some
piggybacking
> now and then, and even an occasional prime focus if it's not *totally*
> impossible, but I definitely know not to expect much. Again, this will be
> mainly for visual use.
>
> Thanks again, you guys are great...
>
> Rex
>
>
>
>
>
> -----Original Message-----
> From: Torsten Clay [mailto:tclay@theriver.com]
> Sent: Tuesday, March 12, 2002 1:10 AM
> To: 'astro-photo@seds.org'
> Subject: Re: [APML] 8" Reflector decent enough for prime focus AP?
>
>
> On Mon, 11 Mar 2002, Rex Moore wrote:
>
> > The introductory email said all levels of experience are welcome, so I
> hope
> > you don't mind a question from a rank beginner!
> >
> > This Orion SkyView Deluxe 8 EQ Newtonian is about at the limit of what I
> can
> > afford to purchase right now:
> >
>
http://www.telescope.com/cgi-bin/OrionTel.storefront/3c8d7c3a03724cb02719c0a
> > 80a6506d5/Product/View/A319
> >
>
> I can see a few potential problems:
>
> 1) the focuser is 1.25", which is not big enough to fully illuminate the
> film. You will get a "porthole" in the middle of the frame.
>
> 2) even if you replaced the focuser with a 2" model, the secondary mirror
> is going to be too small to fully illuminate the film
>
> 3) you might need to move the mirror forward to get the camera (especially
> if you use an off-axis guider) to focus. Usually not hard to do
>
> 4) the mount is going to be a little weak for prime-focus work
>
> 5) you will really want a coma corrector at f/4
>
>
> Another option is to forget prime-focus for the time being, and do some
> wide-field piggyback photos...you will likely get much better results and
> many fewer headaches!
>
> Torsten
>
>
>
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