How much do I need to concern myself about this? The result seems reasonably ok, but could be better. Yet, with my current setup I don't see what I can adjust.
The Feathertouch focuser has a helical clamping 2" opening, as does the Baader. I cannot feel any free play at all, nor do I see anything adjustable by me in any way. Is there anything internal to the focuser that might be adjustable? I'd thnk not because that might mess up the scope for visual work. (I assume it was properly collimated leaving the factory.)
Yes, I realize I focused on a star off center. Would that invalidate the readings from CCDInspector?
Think you need to try again but focus on a star in the centre, not the edge, that way you can measure curvature which I think is whay you are seeing at the moment.