AM5 guiding issue, random RA instabilities: Page 2

AM5 guiding issue, random RA instabilities

Rudy-uit-Dordt

Just to add to this thread (I already made a support ticket), I have the same situation.
I bought my AM5N in february this year and since recently I got periodical spikes in my RA. I got it running through my ASIair plus and using all of the regular settings which worked fine in the past. As an additional remark; it only happens facing east, after the flip facing west all is just fine an no spikes are appearing.

KHj89YaN

Rudy-uit-Dordt

Indeed, as has been relayed to me by ZWO USA, this how all the affected mounts progress. They are only usable tracking setting objects to the West.

KHj89YaN

Herost

I would submit a RMA ticket if you haven’t done so already and post back your information here. Are you in the United States? I’ve received some interesting information from ZWO USA repairs regarding the prevalence of this issue, but I’m sure those numbers are for use purchases only.

Rudy-uit-Dordt

KHj89YaN I'll keep you updated on the status of my ticket. But as it stands now I can't use the mount and is my hobby standing still :-(

kaelig

Tech@ZWO
Good Morning, I have not done the modification belt for the moment. I want to characterize the mount behavior before and after the modification. Under Windows, with PHD2, I could disconnect the guiding orders send to the mount in order to characterize the mount. Could I characterise my mount with the Asiair? I see two possible solutions;

1) disconnect the USB cable between the Asiair & the mount
2) set the RA & DEC agressivity to zero in order to avoid guiding command towards the mount

I have verified my mount. In June, I have update the firmware of the mount because I receive a request message.
I have the 1.5.6 version, could you post the 1.5.1 firmware version in order to come back before the update.

I try to make a "report" in order to help you in your investigations & solutions.

Thank you for your help

Mxc89ZQV

I am experiencing the same problems. They started slowly about 10 days ago and have gotten progressively worse, to the point that the AM5 is no longer useful as an AP mount. I will try adjusting the belts to see if that helps, but this does seem to be a mechanical problem.

kaelig

Mxc89ZQV
I understand what you live. I wait answers, I continue investigations. As you, I have tried to adjust the belts. I wait clear sky in order to test my changes. In parallel, I have build a solution with mini-computer & NINA in order to see if it is a mount issue or a soft issue.

My opinion for the moment: a conflict between the mount firmware & the multi-guiding soft.

What I could not explain, it's why it becomes worst and worst after each session. Is an internal reference value change after the issues that generate a bad slope? I have tested a lot configurations with the Asiair & without sucess. I am very annoyed by this situation.

Mxc89ZQV

kaelig
I think my problem is resolved, the symptoms were:
Guiding started to deteriorate shortly after updating to the latest ASIAIR v2.4.2
Over a period of about 10 days, the symptoms progressed from slight comet tails on the stars to crazy high guiding numbers such as 150 (yes, 150!) on RA and 15 on DEC which rendered the mount unusable.
If I turned guiding off and attempted to track a target, there was a lot of linear movement in the image in just a 30 second exposure.
If I tried to guide on a target in the west that was close to the horizon, total guidance was at about 2.0. Guiding in the east yielded a total of 50 or more.

I checked the tightness of the RA and DEC belts and they seemed good, but I tightened them anyway.
I updated the firmware in the mount to the latest (v1.7).
While poking around in ASIAIR I found it contained almost 600Mb of cache data, so I cleared it.
I reassembled the system, polar aligned, and did a full guiding calibration.
I then set up a live image plan on M31 and let it run for 3 hours using 180 second exposures. The image looked great with a guiding total of .5

I think you were correct when you suggested that the problem appeared to be software. I think the fix was updating everything to the latest versions of firmware, clearing the cache, and calibrating guidance.

So, my 3 year old AM5 is back in service, but this issue is just a continuance of other issues caused by ZWO's software. I can't enjoy my hobby like this. I have purchased a Sky Watcher EQ8-R Pro and a MELE 4c that I am going to load up with NINA. Time to move on.

Support@Seestar

kaelig If you can't resolve it, could you please contact technical support through this link https://support.zwoastro.com/ ?

F5146666

Try to give the RA-axis a couple of turns in both directions in full speed. This could probably help.

kaelig

F5146666

What do you mean? could you explain for me and for the other readers,

Thank you

F5146666

kaelig

Turn your RA-axis/harmonic drive without equipment attached to the saddle with the maximum slew rate possible fully in both directions (a couple of times). This distributes lubrication and reduces static friction (at least a bit) and consequently reduced the occurrence of RA-spikes/issues for some people at least temporary.

I am curious if this improves the situation also with your error patterns.

Andreas

o82KUdLn

Just for the records, I am affected as well.
I own 2 AM5N mounts and I can confirm that one mount suffers from the issue, the second one is fine. For me the spikes occur rather irregular:

after meridian flip, tracking is fine:

As I have 2 different rigs (all ZWO stuff, ASIAIR, EAF, EFW, scopes are Takahashi Epsilons), I exchanged equipment with no effect, The bad mount keeps showing the spikes. I tried all kinds of guiding settings. Lowering max RA duration could reduce the size of the spikes, but not avoid them. Reducing guiding exposure to 0.5 or even 0.2 sec also could not avoid the spikes.
Curious to see if there will be an RCA from ZWO.

Regards, Thorsten

o82KUdLn

o82KUdLn
I did the exercise of removing the payload and then rotating the RA axis of the AM5N mount by up to 360 degrees in both directions several times.
Since then, the spikes are gone and tracking looks ok. I had only few nights since then so I cannot tell if it is a long term solution. Also night temperatures dropped as autum is kicking in. So cannot tell if it is maybe just the lower nighttime temperature or the exercise with RA rotation.

Maritime

I feel for you guys and I’m glad I sold my am5. Zwo support is awful. Endless, useless, frustrating delays and loss of use. I am moving to Nina and moving….

KHj89YaN

Mxc89ZQV

I've continued tracking this issue and I wanted to verify that your issue was resolved by downloading the latest firmware, clearing cache, and calibrating guiding? This would be the first instance that I've tracked that has been resolved with software. For mounts in the USA, it does appear that ZWO USA is now going straight to replacement rather than trying to have users make adjustments.

Totally understand you moving on, the overall blackhole of information from ZWO is unfortunate and not something I expected. Having to learn about AM5N issues from the repair technicians and not ZWO is a problem.

Side note, it appears that an user on Cloudy Nights disassembled their AM5N and found that the LHN gearbox wave shaped washer causes fiction to the wave generator causing the large "snap-back/rubber band" corrections in RA.

kaelig

Support@Seestar

Ni hao,

Since our last exchanges on this post, I have made several actions:

1) I have contacter your technical support, answer: it's the wind !!!

2) I have contacted "Optic Unterlinden" in France (Colmar). I have send the datas, I have made different tests.
For the test, I have removed the Asiair and replace by a mini-computer with Windows, NINA and PHD2.
I have made two tests:

guiding & disconnect the commands towards the mount to see the mount behaviour.
autoguiding without dithering

I have also make the belt tension change ... it is a little better but there are a lot of spikes and the guiding curves are not very regular (as they are in the past).

I have send the datas, OU has identified an issue with 1095s repeat time ... OU has contacted ZWO, I have just received the answer today: make new test on a different place with target in an another part of the sky.

Here is the PHD log of the last night. There is not a lot of period of good guiding due to the clouds.

phd2-guidelog-2025-09-11-231419.txt

2MB

I will make them as soon as the sky would be clear, but ... How many tests I must make before a return for repairing ?

Support@Seestar

kaelig
According to our technical team’s analysis, there doesn’t appear to be an issue with the mount itself. Based on your guiding log, the irregularities are more consistent with environmental factors:

Environmental influence (wind, turbulence, etc.) – this is the most common cause of the spikes you observed.
Guide star jump / sudden displacement – this may happen if the guiding software switches to another star, or if there is a sudden vibration or movement of the guiding camera.
Cable drag or tension – if cables are not well managed, they can pull on the mount during tracking and cause guiding errors.

So from the current data, it does not look like a hardware problem of the mount itself. We suggest checking these factors first before considering further action.

KHj89YaN

o82KUdLn

Glad you have been able to get the spikes under control--at least for now. I find it odd that ZWO keeps suggesting that there is a cable drag and/or atmospheric conditions are the cause when band-aid solutions like rotating the mount on the RA axis seems to temporarily remedy the issue. That would stand to show that there's probably a mechanical issue in the mount that is the root cause of the issue. ZWO USA has stated that all repairs they have made have been band-aids (including suggestions to rotate the RA axis) and the mount eventually return to an abnormal state. ZWO USA has also started to ship out replacement mounts since they can't seem to find a repair solution. Many of these posts regarding the AM5N appeared around June-July 2025 and there is still no definitive answer from ZWO as the root cause.

On a side note, there have been several Cloudy Nights uses whom have disassembled the mount and found that the root cause was the wave shaped washer in the LHN gearbox causing static friction. I am starting to suspect the issue is in this gearbox and probably has to do with how the washer was manufactured by whatever supplier ZWO uses.

F5146666

o82KUdLn

Good to read that this workaround seems to have worked also for you! (even if just temporary) Please keep us posted how this develops over time on your side.

I also did not have any RA-issues for now since I swapped back my RA harmonic drive (<0.9" total RMS). But I had the advantage that I could spin my drive with a power drill when I had it removed from the mount before installing it back again. As I only collected about 10 hours of guiding since then, I will continue testing and keep sending the PHD2-Logs directly to ZWO for review. Let's see, if the RA-spikes are coming back.

Andreas

retman

KHj89YaN i sure hope someone at ZWO is aware of the Cloudy Nights posts regarding "stiction" issues and the wave washer. I apologize as i don't know how to copy them.

Support@Seestar

KHj89YaN
You’ve provided a new perspective that I find very valuable. Our current line of analysis is a bit different, but we’ve already made some progress. We will definitely take your idea into consideration, thank you.

KHj89YaN

retman

That's probably a long shot. The issue is apparently still a very small problem (according to ZWO USA), but I suspect that's due to a lack of reporting and opening of RMA tickets. Users are posting more on here or on other sites which is fine, but RMAs should also be opened so there is a continued flow of cases.

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