If someone is having trouble focusing sct with the primary mirror, the first question I would ask is - Is the focus curve being taken with the knob turning counter-clockwise? This is important for repeatability and it is advice given to people who are new to sct’s and using them visually.
The next question is how much backlash compensation there is in sgp. There is no point in talking about it in terms of steps since the steps can be varying size - but it does make sense in terms of how far the focuser knob turns to remove backlash - and for me it is about 1/2 turn of the knob.
I didn’t look at the focus packs here, but the first curve looks fine except for the very first point (which is on the right since focus always goes right to left with sgp - and that could be clockwise or counter-clockwise in terms of the knob).
There is indeed a need for the system - any system - to settle a bit after a focus change, so sct’s are no different. In my case there is an inherent delay when using my atik 383l+ with autofocus - but with other interline cameras such as sx, there is no delay and the focus image happens too quickly and often shows slight blurring. A delay of even 1/2 second would make the difference between autofocus being useless - and autofocus being excellent.
I placed a request for such a delay during autofocus and was told 1) It should be the job of the focus driver to delay appropriately or 2) The need for such a delay indicates poor equipment that is not worth trying to fix. I find both responses unacceptable since the focus driver has no idea what the overall system settle time is - and it is the job of the system integrator (sgp) to handle that - which it does already with delays throughout. This is just one more delay that is also needed. And - sct’s take excellent images when focused properly with the primary - and there is nothing poor about them for that purpose. My long exposure fwhm’s are now in the low 1" and there are few results with sgp on any system to compare with that.
If you or others find you need a focus delay - I would add to that request if it still exists in the system - or make a new one.
So - in summary make sure the autofocus direction is ccw and you have adequate backlash compensation entered for at least about 1/2 turn of the knob. Make absolutely sure there is no slop in the focus driving mechanics. If you still can’t get consistent curves then try increasing the backlash compensation.
If you get things set right - as I have with C11, EdgeHD8, and EdgeHD11, you should be able to get good focus curves and, after taking one curve and finding focus, doing it again should trace out a well-centered parabola with nearly the same focus value.