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INDI Library v1.9.6 Released (21 May 2022)

Bi-monthly INDI Library released with new drivers and bug fixes.

Tips for Auto-Focus

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Replied by Doug S on topic Tips for Auto-Focus

Hi Peter, this isn't about any specific setup. It's about a general failure to understand basic principles (e.g. averaged sampling, polynomial regression, and flawed reasoning regarding a single seeing affected HFR vs the entire autofocus measurement set). The developer has a fairly long focal ratio instrument (wide CFZ), so is less affected by poor final position than those with short focal ratios (narrow CFZ). As such, getting close was "good enough". Precision was never the goal. This is all-too-often a trademark of amateur / hobby development. All I can say is that it's fruitless to continue this discussion here in the forum. You (and others similarly affected) should send Jasem a PM if you feel strongly about having this finally fixed.
RASA11, Celestron CGX-L, ASI183mc Pro, 60mm guider + ASI290mm mini, ASI EAF focuser, PPB, Rpi4-4Gb+SSD, Powered USB3 hub, hardwire Ethernet.
The following user(s) said Thank You: Sonny Cavazos
9 months 5 days ago #76096

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Replied by Sonny Cavazos on topic Tips for Auto-Focus

I can build on Linux, and I have a GitHub account as well. I cannot build a windows build, I get those from binary-factory (Jenkins).

I use the windows environment on my Home PC connected to my scope via Ethernet to an Ubuntu Build outside.

I have created an issue for this. I will keep you guys updated on its progress.

I would like to get a copy of your fix, I may run ubuntu inside instead of Windows to fix the focus issue for me.

Thanks!
9 months 5 days ago #76124

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Replied by Doug S on topic Tips for Auto-Focus

Hi Sonny, I sent you a PM. We can deal with any questions via PM from here. CS Doug
RASA11, Celestron CGX-L, ASI183mc Pro, 60mm guider + ASI290mm mini, ASI EAF focuser, PPB, Rpi4-4Gb+SSD, Powered USB3 hub, hardwire Ethernet.
9 months 5 days ago #76125

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Replied by hades on topic Tips for Auto-Focus

Can I somehow specify the maximal number of steps during focusing? I am using Linear algorythm and yesterday something goes wrong. The focuser was focusing more thant13 steps during first set of steps (before changing to half step size). The V-curve was no more a V-curve as the HFR after 6th step turns lower. It seems that I have accidentally changed one setting in my DeepSkyDad AF3 focuser driver: step size from 1/8 to 1/2
8 months 3 weeks ago #76509

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Replied by Peter Kennett on topic Tips for Auto-Focus

I always get the same issue - in that EKOS calculates a good curve after 6 or 7 steps, but for some reason it continues to do a dozen or more additional steps that are never needed.  
In this attached screen shot you can see that by step 6 there is a good curve,  But it continues on for 10 more steps in the same direction needlessly.  How do I fix this?  

 

  

iOptron CEM120 EC2 and CEM25P
Celestron C11 EdgeHD
William Optics Star71
ASI 1600Mm Pro, ASI 462MC
Moonlight motorfocus & Esatto focuser
LodeStar X2 and ZWO OAG
DewBuster
NANO PC-T4
Last edit: 8 months 2 weeks ago by Peter Kennett.
8 months 2 weeks ago #76593
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Replied by hades on topic Tips for Auto-Focus

This the same problem I have observed. Thank you for the screenshot Peter
8 months 2 weeks ago #76594

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I think "Out step multiple" set to 2 is too few: you have only two shots on the right-hand side of the V. Have you tried with a value of 3 or 4?
My two cents.
8 months 2 weeks ago #76604

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Replied by hades on topic Tips for Auto-Focus

My setting for "Out step multiple" is 3. But I don't understand why there is 10+ iterations for first right-left cycle? Is it possible to made it more "inteligent" and once there is an obvious curve, the algorithm will do second cycle?
Based on screenshot from Peter, the second cycle could start right after 8th iteration has been done.
7 months 3 weeks ago #77368

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Replied by Jasem Mutlaq on topic Tips for Auto-Focus

That's how Polynomial algorithm behaves. I suppose Linear algorithm needs more data points.
Jasem Mutlaq
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7 months 3 weeks ago #77369

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Replied by hades on topic Tips for Auto-Focus

Thanks Jasem, I will then try to switch the algorithm to Polynomial
7 months 3 weeks ago #77372

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Replied by Giles on topic Tips for Auto-Focus

The linear algorithm was developed to overcome certain issues that people experience. More likely for when there is a certain amount of backlash and perhaps when you're not using a stepper motor. It takes longer to achieve focus, but I think people get better results.

If your AF has a stepper motor, and the backlash is minimal, or able to be compensated for, then I would normally use the Polynomial algorithm (which I use now, and usually get good results).
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I blog my progress: www.coochey.net
7 months 3 weeks ago #77376

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Replied by hades on topic Tips for Auto-Focus

I have DeepSkyDad AF3 focuser with NEMA stepper motor. I will try to test both algorithms tomorrow
7 months 3 weeks ago #77378

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