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Hi Paul,
Unfortunately, until someone writes an X2 driver for the ASA focuser I'm stuck doing manual focus. I'm not sure that I trust @focus anyway.
The tube of the ASA is indeed CF, but I think that the focus shift is from the mirror cooling down, or the Wynn corrector, or the large lumps of aluminium in the focuser. The CFZ for the scope is about 30 microns, I normally focus in 10 micron increments, after initial cool down (i.e. sunset) to stable focus is normally an hour or so and the focus will shift by between 30 and 50 microns. On hot days and cool nights I don't reach stable focus for about 2 hours.
I think I've had a bit of mis-collimation as well, which has had be struggling to get (and keep) round stars. Hopefully that's now fixed.
Cheers
Stuart
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