How does Astroart autofocus compensate for backlash?

Cameras, telescopes, focusers and other hardware
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Rudi
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Joined: 08 Jan 2019, 04:47

How does Astroart autofocus compensate for backlash?

Post by Rudi » 05 Nov 2020, 05:15

How does Astroart compensate for backlash when performing autofocus?
Does it use Absolute, Overshoot or another algorithm?

I would like to know, so that I know what to enter as backlash in my setup.
If Astroart is using the Absolute algorithm, then it is important to enter the exact measured backlash.
If Astroart is using the Overshoot algorithm, then one can enter a backlash value some times larger than measures, e.g. 4x, to be on the safe side.
/Rudi

fabdev
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Joined: 03 Dec 2018, 21:43

Re: How does Astroart autofocus compensate for backlash?

Post by fabdev » 05 Nov 2020, 11:09

Hi, if backlash is enabled in the software then all movements are performed in the same direction. This means that a movement may be prepared going back by a certain amount. This amount is quite high (a full autofocus step), so for example 200 steps. This is possible because focusers are quite fast compared to telescopes in DEC. Also, all backlash steps are printed in the LOG panel and can be verified.
Fabio.

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Rudi
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Re: How does Astroart autofocus compensate for backlash?

Post by Rudi » 05 Nov 2020, 11:46

Thanks Fabio - does that mean, that AA uses an Absolute algorithm?
/Rudi

fabdev
Posts: 230
Joined: 03 Dec 2018, 21:43

Re: How does Astroart autofocus compensate for backlash?

Post by fabdev » 05 Nov 2020, 12:01

No it seems to me a different algorithm. I would call it the "same direction" algorithm.
Going in the same direction guarantees that the focuser is returned to the same places where the measurement steps were tried.
The actual numeric position does not matter.
Fabio.

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