EAF using ASIAIR with Edge HD8 SCT focus knob

vschneck

Previously I had the Celestron focuser on my Edge HD8 and could specify a number of steps to go past the desired focus when the mirror was moving with gravity (down) and then come back to the desired focus against gravity (up) to prevent mirror flop. NINA allowed you to specify this number and it worked quite well.

I switched to the ASIAIR and now use the ZWO EAF. I know you can specify a backlash up to 255 steps. But I don't see how the ASIAIR knows how to do this when the mirror is moving with gravity and therefore needs to go past the desired focus setting and come back against gravity.

Of course if I am manually doing focus I can go past and come back (if I need to turn the knob clockwise I'll go past and then turn counter-clockwise to finish. However I've read the Auto-focus, always goes in the same direction so slack is taken up automatically. This would be true for a Crawford focuser. But that's not the same thing as mirror shift.

Does anyone know if this is a problem with the ZWO EAF And ASIAIR?

Tech@ZWO

vschneck
The backlash setting on ASIAIR is used to add the backlash steps when changing the rotation directions.

Also, the EAF shaft is fixed if you don't run it. so even the gravity affects the focus, the step value should not be changed, so It is not helpful to remember the number of steps in focus.
And Gravity shouldn't have much effect on the focus of Edge HD8 SCT telescope.

vschneck

Thank you for your reply. I think you are saying that for the auto focus the backlash setting of 255 which I currently use will allow the focus to be approached from both the with gravity and against gravity directions which is great. What makes you say the Edge HD8 does not have problems with mirror flop?