Electronic focuser options

[Peter Ward]

Originally Posted by joshman

my understanding is that the critical focus zone is a function of the physical parameters of the scope, and nothing to do with the manufacturers quality.......

Disagree. Dick Suiter's book on star testing 'scope optics ponders this at length. Excellent optics "snap" into focus.

Those with SA or some other fault never really reach focus...they sort of endlessly mush through it.

Thats said, sure, faster optics have tighter zones and are more sensitive to focal plane tilt etc., but it's often the case that a whole lot more needs to be on the money first.

[joshman (Josh)]

Originally Posted by Peter Ward

Disagree. Dick Suiter's book on star testing 'scope optics ponders this at length. Excellent optics "snap" into focus.

Those with SA or some other fault never really reach focus...they sort of endlessly mush through it.

Thats said, sure, faster optics have tighter zones and are more sensitive to focal plane tilt etc., but it's often the case that a whole lot more needs to be on the money first.

Interesting, I'd be keen to see the quality of AP scopes. I've only ever heard good things about them.

[DavidTrap (David)]

I recall reading something about focus motors attaching to the coarse knob being better because it removed another 10:1 gearbox that introduces slop/backlash. Nonetheless, my focus motor attaches to the fine shaft of my AP scope. Random checks of autofocus with a bahtinov mask have usually been satisfying.

DT

[lazjen (Chris)]

I got the Posi Drive for the Feathertouch on my scope. I control it via the Pegasus UPB.

It seems to work very well, but I can't really recommend it, because they're basically out of stock and difficult to get.

[gregbradley]

Originally Posted by lazjen

I got the Posi Drive for the Feathertouch on my scope. I control it via the Pegasus UPB.

It seems to work very well, but I can't really recommend it, because they're basically out of stock and difficult to get.

I have a POSI focuser but Starlight sent me the wrong model. I am hoping they will take it back and swap it out for the correct model.

Greg.