Quote:
Originally Posted by JohnA
so to answer my own question, it would seem the duo will not play well with the non edge c925 so OAG is really my only choice.
I was then torn between the ZWO oag-l and the celestron.
I like that the zwo was slimmer but can only work with filter wheels and not the filter draw and i also didnt like that its all bolt on, so cant rotate camera without an added electronic rotator.
So i opted for the celestron with the 174.
They arrived yesterday and i know everyone says focus them during hte day first, but i though, ill give it a shot at night.
I was dreading trying to focus them all at night, but i got it within half an hour and had both cameras in focus.
What i did find though is bugger this whole 55mm backfocus.
If i was to use the full 105 from reducer to camera, i was struggling to achieve focus on the main camera.
I ended up with 79mm which worked a treat and after plate solving it gave me a focal length of 1475 which is very close to the theoretical 1480mm
So im no buying this whole 55mm back focus hocus pocus stuff
Anyways, it all seemed to work well, managed to polar align and have it tracking.
I'll set it up on the next clear night for a full session and see how it all goes and report back
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The 55mm back stuff as you call it is more for the refractors. Each scope has different backspacing requirements but most are the generic 55mm. An SCT has different backspacing requirements as opposed to a refractor. Also it's dependent on the scope, the reducer etc. Always look at their requirements not the camera's