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Re: [APML] 8" Reflector decent enough for prime focus AP?
Hi Rex,
If I may jump in here .One could also build a barndoor tracker for almost
nothing ,off the shelf. Though limited in size of camera and lenses. I have
seen very nice work from BarnDoors. I have built them from hinges and
mounted them on fencepost. A search for BarnDoor Trackers will net you some
great ideas!!
I'm sure there are others out there who started very meagerly and learned as
they went.
Ray Rochelle
----- Original Message -----
From: "Bert Katzung" <katzung1@attbi.com>
To: <astro-photo@seds.org>
Sent: Tuesday, March 12, 2002 7:49 PM
Subject: Re: [APML] 8" Reflector decent enough for prime focus AP?
> 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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> >
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>
>
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