Hi all, I've got a ZWO EAF connected up to my Skywatcher Esprit 100 and after some mucking about with the bracket etc think I have it all rigid now. Since it's been (of course) cloudy for ages here I've used SharpCap's contrast-edge-detection autofocus routines to test it out in the daytime pointed at distant stuff.
I noticed that if I scanned for focus in the OUT direction vs IN direction, the "Best Position" value found was different by large amounts (~1000 steps) between the directions even though the actual position on the focus tube was the same. So obviously some backlash there and quite a lot of it! I've since re-tightened everything, changed how the bracket is fixed, and remeasured the backlash and now have a value of around 65-70 (still needs some fine tuning measurement). When this is entered into the EAF ASCOM settings, the focus point found is more or less the same in the IN and OUT directions (within ~20 steps), which implies to me that the backlash is now being pretty much compensated for.
My question is, is this a reasonable expected value for the backlash to end up at? What kinds of backlash values have other people ended up needing in the EAF ASCOM settings in order to get repeatable focus positions in both directions? Do I need to revisit again the fixings or the possibility that the EAF itself has too much "wobble" internally and needs exchanging?