Polar alignment error increasing by itself at somewhat constant rate?

lucasdanda

Hey guys,

For some reason, I've been having lots of trouble polar aligning my Az-GTi mount with the All Sky Polar Alignment (ASPA). I'm using the old white ASIAir version, coupled to a Sky Watcher AZ-GTi mount in EQ mode through an EQDirect cable. I've never had trouble polar aligning with the ASPA feature in the ASIAir app, since I don't have a clear view of the south pole (Recife, Brazil). However, ever since the ASIAir app updated to the 2.0 version, I never managed to achieve accurate polar alignment again, although I'm not sure this has to do with the update. I'll describe the problem below.

After a normal ASPA routine, while in the "polar alignment correction screen", the error keeps accumulating by itself each time I press Refresh, at a somewhat constant rate, say, ₃' per Refresh every ₅ sec. For instance, if I just let the mount alone and wait a couple of minutes, the error sum reaches up 2-3°. The curious thing though is that if I just restart the ASPA routine, the error returns to the same initial values, and starts increasing again at each refresh I press. It's almost like the mount is not tracking while the ASPA is being executed.

I experimented using my mount in Alt/Az mode with the SynScan App, just to see if it can still track, and it can. I also tried turning the tracking Off and used the normal non-ASPA routine. Also tried to run the mount with different batteries, power source, and the ASIAir through Wi-Fi. No luck... Don't know what to do anymore 🙁

Corsair

lucasdanda I've been having lots of trouble polar aligning my Az-GTi mount with the All Sky Polar Alignment (ASPA). I'm using the old white ASIAir version, coupled to a Sky Watcher AZ-GTi mount in EQ mode through an EQDirect cable.

Just curious:

Is everyone here who has commented they have this issue using the original ASIAIR?
What mount are you using?
What camera are you uinsg?

Walf@ZWO

Please try this one.
Android： https://www.pgyer.com/9UZT
Password：zwo123456
iOS： https://testflight.apple.com/join/27t20sF7

lucasdanda

Dear Walf,

After a long cloudy period, I finally got an opportunity to test your ASIAir app version. During this time, I managed to exchange my AzGTi mount for a brand new one, just to eliminate an error source. The problem was not solved though...

Here is a video that shows exactly how it goes.

whatsapp-video-2023-01-22-at-92422-am.mp4

10MB

Really don't know what to do anymore, almost quitting the whole thing hahah. Maybe I'm just doing something wrong?!

Ps.: the video shows the error after a normal ASPA routine, with my mount pointing south (latitude ₈), telescope pointing _SE.

w7ay

lucasdanda Really don't know what to do anymore

Ignore the graphics; it is misleading and useless.

Instead, look at the green numbers on the right hand side of the Polar Alignment window. The top set of numbers include up/down arrows and left/right arrows.

Adjust the altitude adjustment knob of the equatorial wedge that mount is placed on to reduce the error of the number with the up or down arrow. Adjust the azimuth adjustment of the wedge to reduce the error of the number with the left or right arrow.

Work on the number with the larger error first before working on the one with the smaller error. You may have to repeat a number of times to get the total error to come down. Just get the total error number below 1 or 2 arc minutes, and it would reduce the field rotation of a 2-minute exposure to an acceptable value (unless you have really long focal lengths).

When you are done, your polar axis should be pointed close to the celestial pole.

Again, do not even look at the graphics on the top-center of that window. It is yet another of a myriad of things on ASIAIR that is confusing and misleading (another you will find is the scale of the small guide window also changes by itself).

Use the numbers on the upper right of that window to make your adjustments.

Chen

lucasdanda

Dear Chen,

Thank you for your reply! Yes, I understand I can completely ignore the top-center graphic. I'm already only paying attention to the error values you mentioned. What my exemple video shows (which is the issue of this topic) is that my error values are increasing by itself, without me making any adjusments to the Alt/Az knobs. You see, each time I press refresh, the altitude error increases a lot, while the azimuth error increses a bit, as if I were messing the the knobs, even though I'm not.

w7ay

lucasdanda What my exemple video shows (which is the issue of this topic) is that my error values are increasing by itself

I don't use ASIAIR's "all-sky" polar alignment. But you might check to see if it requires tracking to be turned on, and if so, check to see if it is on in Mount Settings > Tracking.

Chen

lucasdanda

Wow, can you believe I still have not managed to solve this issue?

It is just impossible to polar align my mount. The problem persists after 2.1 update (I was hopeful that 2.1 could solve the problem).

I'm now pretty sure it has something to do with the way the mount tracks during PA. It kinda looks like it's tracking to the wrong direction... does that make any sense?

w7ay

lucasdanda It kinda looks like it's tracking to the wrong direction... does that make any sense?

Tracking, or the 60º rotation is in the wrong direction?

Tracking is done by the mount, and not the ASIAIR, so, as long as the RA axis of the mount is pointed at the pole (not the OTA, but the polar axis itself), the rotation direction should always be correct. The RA axis needs to point towards north, close to Polaris if you are in the northern hemisphere.

As to the 60º slew, assuming you are in the northern hemisphere, and standing behind the mount, so that the mount is between you are the north celestial pole, ASIAIR does what looks like a 60º counter clockwise rotation.

If the 60º slew is in the wrong direction, check to see if your latitude is correctly set (check the hand controller -- don't believe ASIAIR).

Chen

lucasdanda

Dear Chen & users,

Thank you very much for your assistance. I finally solved the issue by downgrading the App to version 1.9.1. I had to use a 3rd party app store (Aptoide) to install the previous app version. Also, I had to reset the Asiair firmware to match 1.9.1's. This completely solves the issue of the polar alignment. The error was constant every Refresh, and I was able to achieve great guiding results after a 00:00:10 PA error.

Now, with that said, I must say I'm a bit concerned since I'm now stuck at 1.9.1 app version, and am not able to benefit from updates.

How can I report this to ZWO, so that they can investigate and maybe prevent this from happening again (@walf@ZWO) ? I have a friend in the same situation using a Cem25p mount. He also had success with the same procedure I took.

Thank you very much @w7ay!

w7ay

lucasdanda How can I report this to ZWO, so that they can investigate and maybe prevent this from happening again (@walf@ZWO) ?

Try email directly to asiair@zwoptical.com, or if you want to contact Walf; walf.wu@zwoptical.com was the address that I last exchanged email with him.

Good luck,
Chen

Pariah

I have exactly the same issue, trying to use All sky alignment just results in chasing an error that increases the longer it goes on. I posted about this earlier

jpimohr

Yes, it seems to be a softwarebug in V2.0. Tracking is disabled in allsky PA and you cannot turn it on. In V1.9.1 allsky PA ist ok

lucasdanda

jpimohr

Yes, that seems to really be the problem. Tracking shows "On", but in fact is not. It doesn't matter if you manually try to turn it on, it's probably always Off while in All Sky. Downgrading to 1.9.1 solved the issue. I don't know if it's something specific with some mounts; I have information of an AZGti (mine) and a Cem25p. However, if the problem were to manifest with ALL mounts, then shouldn't we have more people reporting the problem? Well, that's something Zwo has to investigate. I'm concerned to be stuck in 1.9.1 now!

@Walf@ZWO could you take note of this and address us any info about it?

jpimohr

lucasdanda I think of is not a mountproblem. Tracking ist turned Off for my AM5-Mount also with asiair V2.0

arakasi

I am also experiencing this issue in Sydney, NSW. The calculated error just changes on its own without any change to the mount. Turning tracking on or off on the mount has no effect on the rate of error accumulation.

Very unfortunate as I had purchased the ASIAir specifically for the all sky alignment capabilities.

arakasi

Corsair

ASIAir Mini
SmartEQ Pro+
Canon 800D

When I have a clear view of the southern sky, the above works great, no complaints.

w7ay

around 5 arc-minute every 5-7 seconds, mostly affects RA but I also notice some change in DEC. I won't trust these numbers too much as I am trying to recall what happened a few nights ago. I will take a video when I can to get more definitive numbers
yes, I am in NSW, approx -34 south

FYI I am currently in contact with Simon from ZWO and will aim to capture a video of the issue tonight.

w7ay

Additionally,

. how much was the reported pole location changing per second of time? And is the change in mostly in altitude or azimuth?

. are you in the southern hemisphere?

Chen

lucasdanda

w7ay

My hypothesis? The rate of change is somewhat equivalent to the rotation of the earth, i.e., the "non-rotation" of the RA Axis. During ASPA, Tracking is supposed to be on (can anyone confirm this?). However, due to an error that we were not able to figure out by ourselves, the equatorial mount of some users is not tracking during ASPA, and a "fake" polar alignment error is added at each Refresh alone. This hypothesis is strenghned by the fact that, if I reset my progress and start a new instance of the ASPA routine, the PA error value returns to the same starting point as before and begins to sum-up again from there.

To date, I'm not able to draw a common cause. It's not a specific mount, Asiair version, hemisphere or latitude range. The only thing I know is that it works fine with Asiair app 1.9.1 (plus matching firmware), which is only doable with Asiair V1. This is confirmed to solve the issue for at least 3 users (including me).

w7ay

arakasi around 5 arc-minute every 5-7 seconds, mostly affects RA

if it were a hemisphere related bug, I would expect 30 arc-second of error for every passing 1 second of time.

Chen

Corsair

arakasi I'm in NSW, too around S 34°, E 150°

I use this tool - https://www.bintel.com.au/astronomy-weather/ - along with the Clear Outside, Nightshift and Good To Stargaze (free version) apps - along with the BOM weather app - to determine if the night is good to set up my equipment.

Tuesday night might be good. Wednesday night is looking good, too. At this stage anyway.

I haven't noticed this issue myself but, then again, when I do the PA routine I haven't tested to see if just leaving it and hitting refresh would do anything. I use All Sky Polar Alignment (ASPA) as well (don't think I get the best view on the SCP).

During the late afternoon, I set my tripod with the N pointing to True South, load it up with gear, balance it, make sure it is in the Home position (counterweights down), turn on ASIAIR, connect to it with the ASIAIR App, go past initial screen, turn on camera cooling to 0°C, then turn on mount, then enable mount in ASIAIR APP.

I then get a rough, daytime, focus on a distant object. Return everything to Home. Put lens cover on scope. Turn off camera cooling and shut down ASIAIR in App. Wait a couple of minutes. Power off ASIAIR. Power off Mount.

Once night hits - power on everything in the same way as before. Once camera has stabilised at 0°C - improve the focus a bit. The do PA routine with ASPA. When I get the screen which tells me how far off I am I just do the "slight adjust - wait 5-10 seconds - refresh" cycle until I get a smiley face (don't bother with trying to get it 0) then hit Finish. Return mount to Home position. Then Sync Mount (under Mount settings). As far as I can tell - mount tracking isn't on during the PA routine - because mount tracking is only turned on once the PA routine completes (I think).

I can then find a star to track, go into Focus mode, refine my focus, return to Home, then Go To my target(s) for the night.

ASIAIR: ASIAIR Plus (32GB - Raspberry Pi based version AFAIK)
Mount: HEQ5 Pro (no Hand Controller - USB 2.0 port on ASIAIR Plus directly connected to the HC Port on the mount using this EQDIR/EQMOD cable - https://www.bintel.com.au/product/shoestring-usb2-eq5-interface/)
Camera: ASI294MC Pro (cooled to 0°C connected to USB 3.0 port on ASIAIR Plus using ZWO USB 3.0 cable).
Scope/OTA: C8 SCT with a 0.63 Reducer
No guide scope. No guide camera. My main use is EAA.

arakasi

w7ay that rate of change I am seeing is a bit higher.

I have managed to capture a video of all-sky PA and the accumulating error issue

https://youtu.be/QzEsnxASHVc

and a standard PA run showing stable error

https://youtu.be/MtbnrHD57ZM

During both videos the mount was not touched at all.