I'm in the SGP 3.x camp. Once you get steps and step size correct for your setup it's great. (There is a specific formula in the doco you need to follow).
I'm running at ~F3.9 with a Newt and even 5nm narrow band focusing works reliably.
There is also a great third party tool called "SGP Autofocus Viewer" that allows you to see exactly what is going on, both graphically as well as tabular. See attachments.
SGP 4.x now uses ASTAP to focus (already uses it for plate solving in 3.x) which is supposedly another step up.
The big question though is do you want to spend money heading this direction, or would Nina for free be a better area to dip you toe into?
|