@Alfred re asymmetric RA motion:

No expert here, but here's a theory.
The mount is tracking in RA, so, RA has no backlash (it's constantly pushing against the gears).
When you give it RA+ pulses, you get the full push.
When you give it RA- pulses, you will go against the normal RA motion and so reverse motion and realize some backlash.
This backlash will cause the system to lose some "push" as compared to the other direction.

The DEC calibration (assuming you have the DEC backlash box checked) removes backlash on the way out, but not on the way back in (where no measurements are made). Dec isn't constantly pushing the way RA is, though, so DEC will eventually overcome the backlash on the way in, but because of the constant tracking RA motion you may always fight backlash in the RA- direction.

Haven't thought deeply about this, does that make sense?
Hy

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