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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

New strange issue with focus position lowering during autofocus run.

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I've been encountering a new issue that I can't explain with focusing. Let's say I start a focus run and I'm at position 5,000. I have a max step size of 300 (which I've now lowered to 150). It will take a focus check at 5,000, then go out to 5300, then start making it's sweep down until I get in focus say around 4500. It then makes one max focus move to the far inside to finalize the curve at say 4200. It says optimal focus is at 4,500, and it says moving back 300 to check focus at what it thinks is the recommended focus. Only, even though it shows it sending a move command, the focuser doesn't move. So the program thinks it back to 4500, but it's actually still at 4200. It checks focus and sees that it's way out of focus (still positioned at 4200. So focus fails eventually after a bunch more focus checks, or it stays out of focus and says autofocus complete even though its not in focus.

At this point, it either restarts, or I restart it. Now it's checking focus starting at what it thinks is position 4200. Finally it will settle with the same issues after another auto focus run somewhere around 3800. After you run this a few times over night, the system finally runs out of focus travel programmatically. It eventually reaches position 0. Even though there is still travel left.

I had been using full frame focusing, and switched to single star because the full frame constantly picks up noise, and struggles with my ASI2600's 55mb file sizes for bin 1x1. Bin 2x2 on my refractor makes the stars as small as a single pixel and can't be used. Here's my focus settings. Also Hy's new method never works for me. It just keeps trying to go smaller and smaller and never stops, and it seems the focuser doesn't move anymore after a while despite commands being sent to move.





Here's a bunch of logs, hopefully showing this issue. I don't remember what log settings I had, but I think focus is on since I've had issues with the Pegasus UPB Driver that moves my Moonlite focuser.

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File Name: log_20-41-49.txt.zip
File Size:284 KB

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File Name: log_21-57-04.txt.zip
File Size:393 KB

File Attachment:

File Name: log_00-00-04.txt.zip
File Size:1,855 KB
3 years 10 months ago #53755

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I've had quite similar issues in the past. For me, the cause has always been mechanical. Either the stepper motor stalls, or the focuser slips. Since you're using a Moonlite focuser (as am I), I had a problem where if I didn't tighten the clutch enough, it would slip. If I tightened it too much, that was bad too. Could it be something like that?
3 years 10 months ago #53758

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I did have it tightened down pretty tight. I had a bit of a tough time making it loose again to check to see it was still working correctly. Slipping was the first thing I thought was happening. But if I try to turn the knob manually while the clutch is engaged, the focuser doesn't move at all. I even tugged and pushed a bit on the camera side of things to see if I could get it to slip, and nothing would move. So it seems it's rock solid.

I could definitely try making the clutch looser, but of course, then it "could" slip. It's strange to me that this happens always at the very last move of the focuser when it attempts to move the focuser back into focus from the last inward travel position. Despite moving it fine all throughout the rest of the curve analysis.
3 years 10 months ago #53759

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It is possible the motor is stalling at this point. But what would cause that? I believe the clutch is just two plastic rings that are pressed together. It shouldn't have an effect mechanically on the motor in any way. I'm also wondering what the life expectancy of these focus motors are. This is my oldest one at almost 3 years old. But I've certainly not used it full time as I have 4 other scopes. So in all, I doubt it's had a full years worth of use.
3 years 10 months ago #53761

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I also have multiple scopes, and only have a Moonlite focuser on one, which is currently not setup on the mount. I'm only going by memory. I seem to remember if it was tightened too much, autofocus would give erratic results like you're getting. I might go plug it in and give it a try again, just to see if I was remembering things wrong.
3 years 10 months ago #53766

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Good to know. I'll keep that in mind next time I get it out. We've got a week of rain and clouds here right now.
3 years 10 months ago #53768

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