Polar Alignment using ZWO AM5N /ASI Air Plate Solving - Forums

Topic starter

Apr 15, 2025

Hi

I live in high rise Apartment with access only to Southern and South Eastern skies. With no direct visibility to Polaris or Northern skies, I end up doing using the Polar Alignment using their 3 Image technique using Plate Solving of ASI Air under PA mode. Typical time taken is roughly 10-15 min to achieve RMS error < 5'

I have noticed that many times even if I don't do any adjustment on RA / DEC settings, the RMS error changes after each refresh as if the mount has physically moved

Any idea how this happens and what is the accuracy /reliability of this entire process.

Suggestions welcome to improve this technique.

Thanks

Mount : ZWO AM5N, Scope : Askar SQA55, Main Camera ASI 533MC Pro

Alex Nicholas

Apr 15, 2025

This is a bug in the ASIAIR that has existed since firmware version 1.9, that ZWO seem 100% unwilling to even believe that it exists, let alone consider attempting to fix it..

Essentially, the Error values change without you making changes to the Alt/Azimuth adjusters, because the the mount is not tracking.

It takes its first image, plate solves.
slews to the next location, takes an image, plate solves,
slews to the final location, takes an image, plate solves, disables tracking.

Because tracking is disabled, each time the image refreshes, the earth has rotated a little, so the plate solve is coming back at a slightly different position on every single refresh.

There is no work around for this issue. Unfortunately, your options are to perform a manual drift alignment, or to manually roll back the firmware version on your ASIAIR to v1.9 - though, this can cause issues with newer hardware for which drivers are not implemented in v1.9 (the ASI220MM guide camera l for example will not work on v1.9.

As far as how accurate the system is? Well… when it works, its PERFECTLY accurate. I have used the same method to polar align my mount in NINA, with the ToupTek StellaVita and with the ASIAIR (v1.9 firmware) and always been able to achieve a sub arc-minute polar alignment in less than 5 minutes…

This is, unfortunately for you, one of those times where ZWO's customer service and support has dropped the ball in a spectacular way, that people tend to forget when jumping on every single product ZWO release…

Sorry I don't have better news for you.

Glenn Baxter

Apr 15, 2025

Hi Aloke,

I have similar equipment and balcony problem (AM5/ASIAir and a north facing balcony in the Southern Hemisphere). My field of view is restricted to the northern sky. I have wasted many hours trying to get the ASIAir all sky polar alignment to work under those conditions - it doesn't even come close. Like you, I found adjustments just gave some random result with no trend or consistency. Probably if there was more of our appropriate hemispheres in view, we would have more success.

To overcome this I use NINA for polar alignment and then for the rest of the session put the ASIAir back in control.

To polar align, I plug the mount and main camera from the ASIAir into my laptop running NINA and the ASCOM ASI Mount driver (available from the ZWO website), connect the driver and then the hardware in NINA, and slew the scope, in your case low SE or SW and use the plugin "three point polar alignment." Under imaging, set direction either E or W and yes for start from current position. Make sure tracking is on in the driver window. Click start and it plate solves three different positions then directs the appropriate adjustments similar to the ASIAir. I repeat the process just to make sure.

You'll have to become a little familiar with NINA which isn't a bad thing, and there will be a bit of trial and error but this will give you good polar alignment.

Good luck,

Glenn

Corentin Martine

Apr 15, 2025

Hello, can it be be movement/ flexure on your balcony (if from a balcony) while you are walking around the setup? Depending how high you are maybe even the building itself wobbling slightly but enough to cause this, by design as such construction is not 100% rigid to better endure conditions. That's what comes to mind when I read about where you shoot from, unfortunately if that is the case not much to do about, except during the captures I'd avoid walking around the setup.

Aloke Palsikar

Topic starter

Apr 15, 2025

Alex Nicholas:
This is a bug in the ASIAIR that has existed since firmware version 1.9, that ZWO seem 100% unwilling to even believe that it exists, let alone consider attempting to fix it..

Essentially, the Error values change without you making changes to the Alt/Azimuth adjusters, because the the mount is not tracking.

It takes its first image, plate solves.
slews to the next location, takes an image, plate solves,
slews to the final location, takes an image, plate solves, disables tracking.

Because tracking is disabled, each time the image refreshes, the earth has rotated a little, so the plate solve is coming back at a slightly different position on every single refresh.

There is no work around for this issue. Unfortunately, your options are to perform a manual drift alignment, or to manually roll back the firmware version on your ASIAIR to v1.9 - though, this can cause issues with newer hardware for which drivers are not implemented in v1.9 (the ASI220MM guide camera l for example will not work on v1.9.

As far as how accurate the system is? Well... when it works, its PERFECTLY accurate. I have used the same method to polar align my mount in NINA, with the ToupTek StellaVita and with the ASIAIR (v1.9 firmware) and always been able to achieve a sub arc-minute polar alignment in less than 5 minutes...

This is, unfortunately for you, one of those times where ZWO's customer service and support has dropped the ball in a spectacular way, that people tend to forget when jumping on every single product ZWO release...

Sorry I don't have better news for you.

Thanks. This is probably the cause. The error is more on RA axis as opposed to DEC. After several trial and error steps, have found a temporary fix by marking the floor for tripod legs whenever I have had the best tracking and then not doing PA at all. Has worked well sofar. Will write to ZWO ASI Air team as well

Aloke Palsikar

Topic starter

Apr 15, 2025

Corentin Martine:
Hello, can it be be movement/ flexure on your balcony (if from a balcony) while you are walking around the setup? Depending how high you are maybe even the building itself wobbling slightly but enough to cause this, by design as such construction is not 100% rigid to better endure conditions. That's what comes to mind when I read about where you shoot from, unfortunately if that is the case not much to do about, except during the captures I'd avoid walking around the setup.

Thanks for the reply. But dont think it is the wobble issue as this is a very stable high rise ( I am on 22nd Floor) and I think the reason given by @Alex Nicholas is probably the cause

Aloke Palsikar

Topic starter

Apr 15, 2025

Glenn Baxter:
Hi Aloke,

I have similar equipment and balcony problem (AM5/ASIAir and a north facing balcony in the Southern Hemisphere). My field of view is restricted to the northern sky. I have wasted many hours trying to get the ASIAir all sky polar alignment to work under those conditions - it doesn't even come close. Like you, I found adjustments just gave some random result with no trend or consistency. Probably if there was more of our appropriate hemispheres in view, we would have more success.

To overcome this I use NINA for polar alignment and then for the rest of the session put the ASIAir back in control.

To polar align, I plug the mount and main camera from the ASIAir into my laptop running NINA and the ASCOM ASI Mount driver (available from the ZWO website), connect the driver and then the hardware in NINA, and slew the scope, in your case low SE or SW and use the plugin "three point polar alignment." Under imaging, set direction either E or W and yes for start from current position. Make sure tracking is on in the driver window. Click start and it plate solves three different positions then directs the appropriate adjustments similar to the ASIAir. I repeat the process just to make sure.

You'll have to become a little familiar with NINA which isn't a bad thing, and there will be a bit of trial and error but this will give you good polar alignment.

Good luck,

Glenn

I was keen to shift to NINA. Unfortunately I am on Mac OS and NINA works on Windows as I last saw on their website. Am contemplating a Windows based Laptop in future and will probably use NINA for everything

Michele Campini

Apr 15, 2025

Have u syncronized the right GPS coordinates to the mount ?