The focussing tool is brilliant - thanks to John and the team for continuing to improve and add functions and options. However, - I have only had consistent auto focussing success with my Celestron 9.25HD SCT and Celestron focuser if I select sub-frame and manually select the star - which means that I can’t set up regular autofocus updates during the night while I’m asleep.

I find that if I select Full Field I get very inconsistent HFR, and large error bars, with flat or no hyperbolic response on the V-plot.

If I choose sub field and auto select, the single star selected is usually very faint - resulting in the same large error bars and flat or weak V-curve

If I choose sub field and manually select a reasonably bright star then everything works perfectly - it is critical to choose a reasonably bright star - not too bright because it may be clipped, and not too weak because hfr will vary randomly between focus frames

I may have missed a tick box or parameter, but the auto-focuser’s choice of the single SubFrame star seems to always be faint, with low signal/noise. Could the auto focuser be coded to select a brighter star from the field? This would result in successful auto focus outcomes every time.

Thanks for your thoughts.

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