Hi El Corazon (or the OP vtanguay or anyone else reading ), do you ever find the FCUSB tries to end up with the focuser trying to keep going in or out (if for examples clouds are in)? If not, how do you stop that from happening. Or is the driver such that if it sees focus is getting worse, it goes one way, and then the other way and so just oscillates around a position. I'm in the UK so clouds can come in and if I'm asleep I don't really want to wake up to burned out motors!
I routinely let FCUSB do unsupervised repeated autofocusing during night. You have to tune the parameters to make sure the focus does not deviate too much for it to recover.
Unfortunately, clouds are a huge problem and if they interfere with an autofocus run, focus may get too far out of whack to recover. The principle of all the algorithms is that you have to start out close to good focus, then let the algorithm optimize it. If focus is too far off to start with, the focuser may not know in which direction to move, making matters progressively worse.
Theoretically it should be possible to return to the start point when using a stepper motor, but I am not sure any of the algorithms accommodate that yet. So let's say, the focuser is unable to achieve an HFR <2 it will move the focuser back to the start position (defined by the user after initial focus optimization at the beginning of the evening) and then start over. That would not be possible with an analog focuser driven by FCUSB.
Perhaps Hy can weigh in on options for improving the focus algorithm and perhaps adding a feature as I just laid out?
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Thanks El Corazon. Yes I normally get it to focus (based on my eyes) so it should be there or thereabouts for further optimisation.
Have you ever had an instance where the FCUSB ends up trying to take the focuser all the way in or all the way out?
I was wondering whether it might be possible to tweak the code so that if HFR is above a user-set threshold value after more than a user-set number of attempts, the driver just assumes the clouds have come in & stops trying to refocus and leaves it where it is. (That way images may be out of focus but that's erasable whereas if the motors burnt out that's more rpblematic). Sorry I'm not a programmer so I don't know whether that's a stupid or undoable idea.