Why must DEC backlash be off in the ASCOM driver when guiding?

Tom Blahovici

I was browsing some forums and looking at the latest ASCOM driver for the AP mounts and I noticed in the documentation that the DEC backlash should be set to 0 when using autoguiders.   The question is why?
My current setup is an AP600e with a TAK FSQ106 and an STL11000 using the autoguider chip with TheSkyX. So 3.6 arc sec/pixel.  Now I find that when guiding (rate is 1 using pulse guide) the mount does a good job with an RMS value under .5arc sec, but I need to keep the aggressiveness down to one.  Any higher and the corrections tend to shoot over the target.
So I am wondering if the dec backlash has anything to do with this.



See what PHD2 says about why it is best to disable backlash compensation settings in the mount.



Tom Blahovici

Thanks. Full explanation.