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

Bi-monthly release with minor bug fixes and improvements

Issue with ZWO EAF focuser

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I installed the new version of the ZWO EAF focuser (USB) on my Celestron 8HD Edge. I followed the calibration procedure from the INDI site... first I set the zero point using the "Sync" button in the INDI Control Panel. That worked fine. When I tried to set the "Max Position" to a number bigger than about 60,000, it screwed up the absolute position field. My focus point is around 100,000 steps with my 0.7 reducer, so this won't work.

I've got a work-around... I set the "zero" point at 70,000 steps and then set my absolute position at about 30,000 to get me to my desired value. This gives me a range of 70,000 steps to 130,000 steps. However, I will need to change my focus point when I use the native focal length or my HyperStar. Not sure I can get to a proper focus number within my work-around range.

Anyone else experiencing this issue?

Ron
1 year 4 months ago #87810

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Replied by Doug S on topic Issue with ZWO EAF focuser

Hi Ron, from one EAF user to another, why couldn't you just focus (with or without EAF), then disconnect the EAF, run it back to a midpoint count between your two setups either with Ekos or the ASI control software, and then reconnect it to your gear? Wouldn't that be sufficient to allow both setups to get to focus within range (i.e. <60K counts)?
1 year 4 months ago #87820

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Yeah, that's kind of what I've done. My focus point is around 100,000 steps, so I set the "zero" at 70,000... which allows me to range to 130,000.

It will just be an inconvenience when I change to my HyperStar or the native F/10.

Thanks,

Ron
1 year 4 months ago #87821

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Doug,

Just curious... are you experiencing the same issue with your setup?

Ron
1 year 4 months ago #87915

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Replied by Doug S on topic Issue with ZWO EAF focuser

Hi Ron, To be honest, it's been so long since I initialized my EAF, I've sort of forgotten about it. When I read your account, I was wondering how you got to 100K counts. I vaguely recall I only was able to go to 60K counts before the upper limit is triggered. From my work with automated focus (temperature based compensation), my focus has remained in a range of 50K to 55K counts (-10C to 25C) for years. I think the only reason why my range has that specific bias is just a function of where it was in counts when I tightened the setscrew on the drawtube shaft. It could have alternatively been anywhere in the working count range of the EAF depending on both EAF motor position and focuser position.

As I indicated in my earlier post, my recommendation would be to achieve focus on your setup, then djsconnect the EAF from the focuser drawtube shaft and run the EAF motor somewhere near mid-range counts (say 30K or so?). Then reset the EAF setscrew to the focuser drawtube at the focus position. That should hopefully put your EAF counts value somewhere in a sweetspot between your two setups, assuming those setups don't have too much offset counts between them.
1 year 4 months ago #87917

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Doug,

Yes, that's what I've done.

The only problem is that I run the scope in a variety of modes... F/10 (native), F/7 (0.7 reducer) and F/1.9 (HyperStar). Each have a significantly different focus points. So I'll likely have to perform this workaround each time... which is a bit of pain.

The reason the count is so high is that the ZWO EAF has 5,760 steps per revolution, which is much higher than my previously used Celestron motor focuser that has 1,000 steps per revolution.

Thanks!

Ron
1 year 4 months ago #87918

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Replied by Doug S on topic Issue with ZWO EAF focuser

Just a thought.... I'd be tempted to identify the most "inward" focus setup, and bias the EAF motor count close to say 2-5K counts (allows for some slop in seeing, temperature, etc.). The other setups being outward from that point might fall below the max count limit....
1 year 4 months ago #87920

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