Thanks for the advice.
> with the medium star size option
Wow, I haven't even realized I can choose the star sizes.
Will try to adjust auto-focus settings as you, @nou and @Jerry Black, suggested. It seems that my step size is still much too large.
I've been using KStars with Pegasus FocusCube v2 for 2 nights and I'm fighting KStars a lot.
If I use the scheduler, it forces the option "Auto Select Star" in the "Focuser" tab. Which leads to all the focusing not being able to converge.
The focuser module, moves the focus outward by a few thousands of steps and takes a picture. All stars are obviously blurred. The focuser module then decides that that galaxy or that nebula is the best star in the image. It adjusts the focus, and every other star comes into focus, but the galaxy/nebula remains blurry. The focuser module reports a failure.
Sometimes the initial outward focus is so large that the stars turn into very large circles. The focuser module finds a tiny bit of random noise and decides that this is the best star in the image. The big circles eventually turn into point-like stars, but the focuser module isn't interested, it keeps looking at that tiny bit of random noise in the image. For this specific problem reducing the initial step by 10x helped. However, if this initial step happens to be too small, the focuser module will not ever go further outward than the initial step.
Without the focuser device, I had moderate success in using the scheduler to image DSO unattanded. Now I got the auto-focuser device, and unattended imaging no longer seems feasible, as it requires constant babysitting.
Please tell me what am I doing wrong. How can I make an effective use of the auto-focuser to let the imaging run unattended?