Auto focus out

Hi All,

Wondering if I could get some advice, please.

I am using SGP ver 4.00.676 with my GT81 and Pegasus focus cube. I have been trying to get the autofocus working.I followed the guidelines as per instructions and UTube clips working out my step etc.I get good v curves with 96-99%.But for some reason, the focus is slightly out by about 100 steps.I put the Mask back on and it is pretty out.Test images show the difference as well between autofocus and manual focus.So I refocus as close as I can and retry and the same thing happens its out about 100 steps.I have tried for hours to change the setting to see if I can get it closer but no luck.

I think I am doing something wrong here can anyone give me some tips please.I have tried 2 different cameras with the same results.Zwo ASI2600MM ASI2600MC.

I have used a different setup with different focuser and get much closer.

Any ideas here please as I am unable to automate the nights imaging if the autofocus gives me soft stars

Thanks in advance

Stu