Help needed, is my mount broken?

Help Needed Troubleshooting
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astro.hamster avatar
astro.hamster avatar

Hi everyone,

I’m looking for some help and advice, I’m currently on La Palma with my travel rig which I’ve previously used on La Palma and Tenerife. I’m using a mini pc to run NINA to control my Umi17Lite harmonic drive mount in combination with a Touptek ATR2600 and SQA85.

For the last few days I’ve ran into some issues which prevents me from using the mount as intended.

  1. Using Three point polar alignment I get inconsistent results every time I rerun TPP, as well as the RA and Dec error changing without me touching the mount. Yesterday I finally had it at least consistent within 3 arc minute I tried to plate solve and tried to point at a target but the mount always pointed in the wrong direction. 📷 wtf.pngwtf.png

  2. In PHD2 I was having issue focusing my guide camera (120mm mini) on the OAG. But once I was in focus then PHD2 did not select a consistent guide star. I’ve remade a dark library multiple time, and tried the guide camera with IR filter and without, but both times PHD2 did not want to play along. https://i.imgur.com/EDunhqO.mp4 PHD2_GuideLog_2026-05-27_192523.txt

  3. After manually slewing the mount from its starting home position the mount no longer returns to the original position once I use the home button.

I’ve updated the gps location in the mount settings during startup with the correct timezone and synced those to NINA. The last PHD log is attached in point 2 and here is a PHD log from the last time everything worked okay. PHD2_GuideLog_2025-09-28_135058.txt

Does anyone have any trick to find the root cause of these issues? Let me know If I need to provide more information.

Well written
Brian Puhl avatar
Brian Puhl avatar

Pointing errors are almost always related to incorrect time and location settings. Verify all this information. I know you said you did, but could you have possibly put a ( - ) negative where it should have been a positive, putting you in the wrong hemisphere? I would verify time and position in NINA, then sync to the mount, personally.

Also, I see in your screenshot you’re trying to plate solve near the pole. This almost never works. Cone error is to blame. Send it somewhere further south in declination and try again.

TPPA is finicky and often will give you different results. Some folks have different experiences, but yours is not uncommon. The rest of us moved to SharpCap’s polar alignment tool. It’s behind a paywall, but very much worth it!

As for your PHD error, you just need to tweak your settings. Initially I’d start with getting rid of star mass detection. Set your min HFD to 1.5, max HFD to like 6 or 7. I think these will work.

I’m not sure why your mount did not return to the home position, it could be possible that because it was out of sync and the mount does not rely on a homing sensor. I dont know much of anything about the Umi. I would troubleshoot this last.

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astro.hamster avatar
astro.hamster avatar

Hi Brian thanks for the suggestion.

So how I see it, the real longitude and latitude are suppose to be this. 📷 real location.pngreal location.pngSo the Western Hemisphere is defined with a -
In NINA it shows up with the minus but if I look into the Onstep settings it says that W is defined with +.

📷 nina and onstep.pngnina and onstep.pngTonight I’ll try to switch this around to see if this has the desired effect. As well as your suggested PHD2 settings.

Brian Puhl avatar
Brian Puhl avatar

According to my research, this information looks correct. Don’t swap. Is your PC clock correct as well?

Also, note the part underneath your coordinates about Onstep not using DST. Verify that your time zone offset is correct, I THINK it should be 0 if Google is giving me the correct info.

astro.hamster avatar
astro.hamster avatar

I will use the 0 UTC time in onstep and see what will happen. My assumption is that the difference in 1 hour of the timezone could not explain the amount of pointing error I saw. I manually slew the mount to Ursa Major and when I plate solved the framing assistent in NINA thought it was pointing at Cassiopeia, so the complete opposite, when I tried to sync the mount tried to correct itself it slowly started correcting towards the ground.

In the last 3 days I’ve had 3 collisions which I think have messed up the encoder offset or something along those lines.

Brian Puhl avatar
Brian Puhl avatar

You know, something I just noticed that I completely overlooked… you have an error at the bottom right that sync is not enabled because the telescope is not tracking.

If the plate solve can’t sync the mount, then it will never find itself. Make sure sidereal is enabled. I know it’s not going to completely fix whatever is going on, but it’s a start.

Whatever this is, it’s something silly and simple.

Helpful
astro.hamster avatar
astro.hamster avatar

When I enable tracking and tried to use the sync from the plate solver then the mount does tries to correct itself which ends up with the scope pointing into the ground. So even when it tries to correct itself based on the plate solve it moves wrongly. This mount has been reliable for the last 3 years when I’ve used it and this issue has never come up before. Based on the behaviour I think you are right that the mount thinks it’s either in the wrong hemisphere or timezone but I’ve rechecked those settings multiple times now and the screenshots show that these settings should be correct.

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TiffsAndAstro avatar
TiffsAndAstro avatar

You said it no longer returns to home.

Just checking if have reset the home position?

Brian Puhl avatar
Brian Puhl avatar

astro.hamster · May 28, 2026, 03:38 PM

When I enable tracking and tried to use the sync from the plate solver then the mount does tries to correct itself which ends up with the scope pointing into the ground. So even when it tries to correct itself based on the plate solve it moves wrongly. This mount has been reliable for the last 3 years when I’ve used it and this issue has never come up before. Based on the behaviour I think you are right that the mount thinks it’s either in the wrong hemisphere or timezone but I’ve rechecked those settings multiple times now and the screenshots show that these settings should be correct.


Understood. I had a feeling that might have been it, but wanted to point it out.

This is almost starting to sound like a NINA to Onstep problem. I really can’t put my finger on it, but it MIGHT be worth starting from scratch with a new NINA profile. From there I’d maybe reset whatever you can with Onstep (I’m not super familiar with OS). As far as I can tell your times and locations are certainly close enough. Like you said, it might be off a bit, but certainly not other side of the world off. I’m about as confused as you are right now.

One thing that i can’t get over is your first screenshot.

You’re showing M51 as the desired target, but you’ve got the wrong RA/DEC input and you’re trying to slew to the NCP, which NEVER works. It will almost always fail due to cone error. I just want to recage here, because I don’t like what you’re doing there.

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