Recently I tried some more night shots pointing as far south as I could.

I didn't know exactly where the south celestial pole is/was, but I tried.

Alas I still got a lot of problems focusing on those little blighters!

Even putting it on live view so the screen at the back of the camera was the display and setting MANUAL FOCUS, the lens's focusing system is touchy to say the least.
Only a SLIGHT touch and the star goes in/out of focus like that!

Is there a way to "cheat" with this?

My only thought was to build a "venere" thingy which gives me a thing to turn and it is geared down to turn the focus ring so SLIGHT adjustments are possible.

How you people with "normal" lenses manage such fine focusing on stars?

(Maybe I've just got a dicky lens with a fickle focus ring?)