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

["Bert Katzung" <katzung1@attbi.com>]

Hi Rex:
I've been watching the good advice you've been getting and agreeing with it
all but before you give up on the idea of any serious astro-imaging, I would
throw in one escape valve for the impoverished aspiring astro-imager: the
moon. You can get very nice moon photos with almost any mount because the
exposures are so short, the tracking quality doesn't matter that much. So
while you're honing your visual skills (and saving up for a good quality
mount) you can be getting some nice lunar images for your office wall. If
you're interested in the sun, you can use similar short exposures for
sunspots, etc. You will need a solar filter for the sun, but you can make a
very good filter from the Baader filter material available from
Astro-Physics for about $40. See http://www.astro-physics.com/ and click on
the icon in the lower right corner. Good luck....
Bert

Bert Katzung
katzung1@attbi.com
www.astronomy-images.com

----- Original Message -----
From: "Rex Moore" <RMoore@fool.com>
To: <astro-photo@seds.org>
Sent: Tuesday, March 12, 2002 7:29 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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