I don't think the image circle comes into play. The resulting FOV is 3436 X D / L where D is the size of the sensor and L is your focal length. So yes, the 120 is a very small sensor and that can result in a small FOV but at short focal lengths like my guide scope, the FOV is really quite nice (about 90 arc-minutes).
I am guessing your CDK has a much longer FL so the FOV will be very small and smaller FOV's take alot longer to plate solve. It is a balance for sure. But actually most people that use ASTAP say they plate solve in literally a few seconds so maybe that doesn't matter. I tried ASTAP and was never able to get it to work. So I use ASPS and it works well but it is slow and a smaller FOV would make it pretty difficult to use.
Thanks for the followup, it helped. We use Planewave's own pointing model software which is pretty much automatic except for picking the number of targets wanted. It's just waiting while it does it's thing. The FL on the CDK14 is 2563mm, so a bit longer than your guidescope. I think a larger chip might be beneficial.
The 120 on the CDK will yield a 6.4 arc min FOV,
the 290 7.5 arc min and
the 174 a whopping 15 arc min°.
The ATIK that I use now provides about 13.7 arc min.
I may have to see if I have the budget for the $500 174 model.
Edited by rockethead26, 06 July 2020 - 06:59 PM.