With regard to guiding I have experienced significant differences between mounts (or their respective drivers). A Losmandy G-11 works perfectly here with dithering set to 10 pixels whereas an LX200basic-driven Alt-5+FS2 (with all other equipment the same) regularly fails to even calibrate. The FS-2 + Alt-5 combination is of high quality and doesn't suffer from backlash or other imperfections that could explain the difficulties. The G-11 however never lost a guide star (neither at 2,8 pixels nor 10 pixels) and that's why I believe the root cause of your problem could possibly be found outside of the "dither code".

Yes, it is certainly possible that the code told the mount to move a certain distance in this direction, and then the code is then looking for the guide star in that new position. However, maybe the mount didn't actually move as far as was instructed (or too far), hence ekos reports it has lost track of the star.

However, it does reacquire the guide star after reporting that it lost it, and it happily resumes guiding. Unfortunately, the capture module is stuck, waiting for dithering to complete, since it was never informed that dithering has, in fact, completed. This only happens when the guiding code loses and reacquires a guide star in the process of dithering.

Ok, so it is my understanding that we're confronted with two distinct problems. 1. The guide module losing the guide star during dithering which should not happen in the first place and 2. the capture module not being informed that guiding has resumed so it should continue taking pictures.

Ok, I see. My frame size is much smaller than yours since I'm using a ccd with a couple thousand less pixels on a side. For a DSLR I could see a larger dither distance since you do have many more pixels, especially if it helps in another way. Are you guiding with PHD2 or Ekos Guide Module?

Using ekos internal guiding

Exactly

Yes, I wrote the algorithm for KStars to continue guiding if PHD2 loses a star and then reacquires it, but not for the Internal Guider. That's a question for Jasem.

I will send him a message.

Thanks,

Rob

Thanks. Yes, this was indeed a corner case which should be fixed in the next version. The fix landed in GIT if anyone wants to test it out.

I'll try it out tomorrow night, thanks!

This issue happened to me last night.
After losing the star the guider module stalls. Even after identifying and reacquiring the star (it puts a circle on it), it keeps saying the star is lost and the capture module hangs in the dithering process. I will test it too, thanks!

This is with the nightly KStars build of yesterday?

Not sure but I think it's the previous version, tonight I will update again and see if there is any change.