Christopher, I agree mostly with what you said. I think in my case, the
rings are old and the felt is pretty much crushed so my 155 isn't moving in
the rings like it might if the felt was thicker/newer.
The main difference between what I'm doing and what most people try is that
I'm not using a small refractor with a cheap focuser for a guidescope. I am
using a Borg guidescope that mounts directly into the ST-402ME. It has NO
focuser. The connection is rock solid. I think droopy focusers on
guidescopes are a bigger problem than flexure of the main scope inside the
rings. My 2 cents - worth every penny!
Like I said, I imaged for years with the set-up I described. 100% round
stars. I "just" put this set-up together again while I do some upgrades to
my primary imaging rig. I'm going to see if they remain attached to this
note but I put them here:https://groups.yahoo.com/neo/groups/ap-gto/photos/albums/116213838
they are removed by Yahoo.
BTW - like you I use an off-axis guider on my primary rig. A MMOAG. But I
don't have all the fittings to put it into the train on my AP155 and it was
an "impulsive" decision to put the AP155 back into action.
On Fri, Oct 14, 2016 at 3:48 PM, 'Christopher Erickson'
christopher.k.erickson@... [ap-gto] <ap-gto@...> wrote:
The only scope I have ever owned that didn't suffer from differential
flexure between a piggyback guide scope and the main scope is my AP
130EDF-GT. That is why I ONLY use off-axis/radial guiders any more.
Over in the Meade Yahoo groups that I haunt (I also have a 16" LX200GPS) I
am constantly amazed over how many scope setups I see where there is an
under-mounted SCT combined with a small Chinese refractor and a floppy
focuser riding on its back. And not an OTA counterweight anywhere in sight.
Of course I rarely see any images taken with those scopes...
Waikoloa, HI 96738
*From:* ap-gto@... [mailto:ap-gto@...]
*Sent:* Friday, October 14, 2016 8:44 AM
*Subject:* Re: [ap-gto] Re: AP900 Gto Auto-Guiding woes.
Vince, you want the guide scope/camera to be fixed relative to the back of
your imaging scope. Ideally mounted on the focuser but with your scope that
seems impractical. You could try a second pair of rings that are lower
profile around the big tube and move them back as far as possible.
What is the focal length of your imaging scope? AP makes a very elegant
guider holder that mounts on the focuser. I'd talk to them about that vs.
what you're trying in the photo if that set-up is suffering from flexure.
BTW - I imaged for years with a 350mm focal length Borg 60mm guide scope
mounted to the top plate on my AP155. I was able to stabilize it fine and
never had an oblong star in all the years I did that. You should be able to
do what you're trying but it may need to be more securely attached than
what I see in the photo. In my case, I had the guide camera, an ST-402ME,
sitting firmly on the top plate of the cradle holding the AP155. The rear
ring of the cradle nestled up against the focuser. The front of the Borg 60
was held in a Losmandy 3-point ring and the body of the Borg 60mm was held
in a second Losmandy 3-point ring. The three points were tightened down
I'll try and get a photo of this set-up.
On Fri, Oct 14, 2016 at 2:31 PM, salfranc@... [ap-gto] <
I am not sure how I can better fit the guide scope to the mount. If you
could give me a picture or something to show me the best way I would be
really happy to modify my setup.
The cables are also showing on the image. I cannot get them any closer to
the centre of the imaging scope as they interfere with the CP3 cables when
slewing east and west.
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