I think from reading your telescope specs, and using 2 arcsecs seeing and 7% focus tolerance, you actually have 62.4um CFZ size (full width). Now, using your 1600 motor steps/rev divided by 2000 um/rev focuser travel, you have 0.8 steps/um or 1.25 um per step. So, you have 50 steps through your CFZ (+/- 25). This is fine. Read those mount instructions carefully. I suspect you'll be using the slow knob, not the 1/10 fine focus. You're sampled sufficiently. You will enjoy the motorized autofocus that Ekos provides. If you have access to a temperature sensor, you may even benefit down the road from automatic focus adjustments between exposures via AFC, but that's a topic addressed by a different thread. Good luck, Cheers, Doug

Read More...