I've been battling with focus in Ekos recently. I'm using the linear algorithm (my focuser has some backlash so this should help out) and that seems to be behaving. But i'm having problems with the star detection algorithm picking up stars that are not stars, getting crazy low HFR values and it keeps going, finding "stars" when I can see the actual star is way out of focus. I've tried this both full field (when it detects the fake stars theres way fewer of them) as well as subframe. Subframe you can clearly see the star is defocused yet its picking up things.

I'm using the SEP algorithm with the default profile, I've tried averaging it over 2 frames, it does the same thing on Lum or Ha or any filter. I'm running 1600mm on an 8" f/3.9, lum I use 1s exposures and Ha 3-5s. I'm more or less sure i've done something wrong but I'm not sure how to fix it properly. Any ideas what I could tweak to help it only pick up the proper stars?
 

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