Auto focus on SCT?


#1

Hi folks, trying the 2.5.1.17 auto focus with an 8" Celestron Edge HD and Starizona MicroTouch Autofocuser.

Although I get a nice inverted V with step size = 30, it doesn’t focus when set back to the tip of the V. I think when you go past the V and then back, some sort of backlash/hysteresis effect is occurring.

I also see this when focusing with a Bahtinov mask. If I overshoot, I often have to step back many extra steps to focus.

Not sure what to do, other than stop auto focus when it looks like it’s at the minimum point? But then it’s a manual process.


#2

You’re right. You have to setup backlash compensation with an SCT.


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