Polar alignment produces absurd correction angles

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Christoph B avatar
Hi,

I am using an ASIAir Mini with a Skywatcher EQ AL55i mount connected via the serial cable (could not get any other connection to work properly). I can control the mount from the ASIAir app and I got my camera and focus set up. Plate solving works and produces correct results as far as I can tell.

I do not have visibility on Polaris although I am on the northern hemisphere. I am working from my balcony where my viewing angles are highly restricted. So I enabled the new polar alignment functionality. I set up my mount so that it faces roughly northward and the inclination matches my geographic latitude. I am pretty confident that I am not absurdly far off.

I set up the telescope to look in such a way that the rotation performed by the polar alignment function will always look at the sky. Then I went into polar alignment mode. The system took the three images and plate solved them. I have to assume reasonably correct.

Then I get the targeting diagram and it tells me I am way off. Like 90 degree horizontally and 50 degree vertically. Something that is completely unreasonable. So, something must be wrong. Any ideas what it could be?

I am coming from a smart telescope background where I just point the device somewhere in the sky, it does a few shots and then tells me how to rotate it. That always works without any problems. I was assuming kind of the same to be the case here.

Thanks for any ideas.
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Quinn Groessl avatar

Ensure your latitude and longitude are correct in the app. And by enabling the new polar alignment functionality, I’m assuming that means you enabled all sky polar alignment? I don’t have an ASIAIR anymore, but it used to be in the experimental features section.

Ethan Sweet avatar
This sounds a lot like arecent forum post.

I can't post links for some reason… Forum->Equipment Forums->ZWO ASIAIR->Inverted World After Polar Alignment

No definitive answer but it seems to be an issue with Sky Watcher mounts connected to the ASIAir.

I have the SA GTi and have a similar issue. I have to release the clutches and manually (by hand) point the scope back to 'home'. Shutdown the ASIAir, fully close the app on my phone. Restart the ASIAir and reopen the app. It then defaults to thinking (correctly) that it's pointed at Polaris. 

It will then slew correctly anywhere in the sky.

Might give that a try.

CS!
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Christoph B avatar
Thank you for the suggestions. Yes, I am referring to the All Sky Polar Alignment feature. I think I checked my location and synced everything to the mount. Looking at the weather, it will unfortunately take some time before I can try anything out now.
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Christoph B avatar
There is one other thing that I noticed after thinking about it and trying again. During the procedure, ASIAir slews the declination axis of the mount. I would expect it to slew the right ascension axis (the one pointing to the pole) instead. Can there be an axis swap? Is there a way to fix that?
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Aloke Palsikar avatar

There was a similar post earlier in this group. If you do not have a view of Polaris it is fine. However pls ensure that your Scope is not pointing full East or West direction at the start of PA process. Anywhere in between is fine.

Hope this works !

Regards

Christoph B avatar
Thanks. I am aware of the limitation. Thing is, I have set up my scope to look into a southerly direction and the All Sky Alignment slews it to the north, rather than east/west as I would expect.
lilian Zhu avatar
Thank you for sharing your experience with the all-sky polar alignment feature. I’ve already passed your feedback to our product manager.

Since you are located in the Northern Hemisphere, we recommend starting the alignment with your initial position pointing toward the northern sky.
If you encounter sudden error jumps during polar alignment, please try returning the mount to zero position and then running the PA process again. This often helps reduce the error fluctuation.

We plan to continue optimizing the all-sky polar alignment algorithm in the next version. Would you be interested in taking the test for the upcoming release? We’d be happy to keep in touch with you.
Christoph B:
Thanks. I am aware of the limitation. Thing is, I have set up my scope to look into a southerly direction and the All Sky Alignment slews it to the north, rather than east/west as I would expect.

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Christoph B avatar
Thanks for your response. Sure, would be interesting to test any updates.
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