Polar alignment error increasing by itself at somewhat constant rate?: Page 2

Polar alignment error increasing by itself at somewhat constant rate?

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.

w7ay

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

May not be a hemisphere error then.

Chen

Corsair

arakasi Oh. I forgot to test this out last night. Dang it.

I was able to use the normal PA routine this time around (not ASPA as I usually do) and didn't bother trying to refine too much once I got into the acceptable range with the smiley face. My aim was to get set up and going to share viewing my son before he went off to bed - school night and all.

That being said when I have used ASPA I have managed to achieve PA success as well. Although I have to say it feel like it did take longer with ASPA than without (although that could be purely subjective as I'm better at the process now than before).

w7ay

@Tech@ZWO

Why are you guys ignoring this problem?

Chen

arakasi

Corsair good to hear people have gotten ASPA to work! At least some people is getting use out of it 🙂

I have shared my videos with Simon from ZWO and he has passed the video the development team. That was 4 days ago, I haven't heard back since.

@Tech@ZWO if there are any updates we would love to hear it either here or via zendesk 🙂

Corsair

@Tech@ZWO So... any response at all? Did you look at @arakasi videos from their post above?

lucasdanda

Guys, check this out:

I was happily using my old Asiair V1 with app version 1.9.1, but then I purchased a new Asiair Mini. This Mini naturally came with the newest app version (2.1), and, as I was afraid of, the ASPA is not working anymore. Same issue, the error keeps accumulating by itself.

Now I don't know if I will be able to downgrade to 1.9.1 again with the Mini, since its firmware is updated past the 1.9.1 app version. I actually tried to install 1.9.1, but then when the app is Iaunch, it says the firmware and app versions are not synced. Despite that I'm given the option to ignore this and enter the app, the problem still persists (polar alignmenr error changing at each refresh, no mount/wedge touched). Maybe this is an indication that the problem might lie within the firmware...? Ps.: when downgrading both firmware & app to 1.9.1, my Asiair V1 works as a charm.

Well, at least for me, it's pretty obvious it's an app-firmware-related issue, since downgrading to 1.9.1 + matching firmware instantaneously solves the issue with ASPA.

Now I'm pretty sad I most likely won't be able to use my new asiair mini... ASPA is a must for me.

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).

Tech@ZWO

bambi851

lucasdanda

We optimated something on ASPA from the V2.0, tracking must to be turned on during ASPA. Some mounts auto stop tracking after meridian,in this case, it will cause some error like you said. So you need to make sure the mount will not cross the meridian during ASPA. AM5 should be done like this as well.

bambi851

I'm having what I think is the same issue.

Just purchased an AM5 and an ASIAIR, 2600MC, EAF, 120mm guidescope (so all ZWO).
I'm in the northern hemisphere (UK).

Unfortunately there is a big tree behind my house exactly where polaris sits, so I was looking forward to trying the ASIair alignment.

Last night was the first night without clouds and I wasted it chasing PA. I would get to about 00,02,50 and then the next refresh it would be 00,07,00 again. This happened in RA and Dec and I was messing with it for about an hour before I finally gave up.

I'm on latest app 2.1

w7ay

bambi851 Unfortunately there is a big tree behind my house exactly where polaris sits, so I was looking forward to trying the ASIair alignment.

You do not need to see Polaris -- FWIW, Polaris is not even at the North Celestial pole, and not used for Polar Alignemnt because of that.

Does the tree create an obstruction more than about 30º away from the pole ? I.e., can you at times see the star Caph, or the Heart Nebula, or Kochab?

If you can see those stars at certain times of the night, you can use the pole-base Polar Aignment by placing the starting declination to something other than 90º.

The equations will work out, althought you will get less precision because of a secant of an angle close to 0.

Take a look at:
https://bbs.astronomy-imaging-camera.com/d/11580-polar-alignment-without-polaris/11

https://bbs.astronomy-imaging-camera.com/d/11643-asiair-polar-alignment-without-visibility-of-the-pole

https://www.cloudynights.com/topic/666852-rainbowastro-rst-135-review-the-ideal-imaging-mount/?p=10253290

In your case, replace the horizontal roof obstruction by the vertical tree obstruction and start the mount at an hour angle not at Meridian, but at some angle on the side of the tree. You also do not need visibility of the sky while the polar alignment process is moving that 60 degrees, You just need for the frame to be clear (to plate solve) at the start and at the end of 60º slew.

Just draw out your horizon carefully and you should be able to find the devlination angle and hour angles that will work. 30º a a large distance in the sky.

Chen

bambi851

w7ay
Hey,
Thanks for taking the time to write.
The tree blocks out about 30º either side of the pole and about 80º up, so I miss a large part of the sky to the north. I saw a video that showed the ASIair PA working if pointing to the south (which is clear for me), so tried that. It seems like the AM5/ASIair crossed the meridian when it selected the 2nd or 3rd star and turned off tracking.

Thanks for the links, I think it will be cloudy tonight so I have lots of time to read 🙂

lucasdanda

Tech@ZWO

Yeah, you guys mentioned this via e-mail. The thing is that I'm not crossing the meridian during the ASPA routine...

I always slew my mount about 80 deg so it can perform the 2 ASPA slews without crossing the meridian, in the direction of the zero position. I have to do this since I don't have a view of the celestial pole (low latitude) (But don't get attached to this, as others have encountered the same issue at higher latitudes). The error still keps changing by itself at every Refresh...

I sincerely don't know what to do. My Mini simply has no use for ASPA. I can only run ASPA with the old V1 with app 1.9.1. Does this give you a hint of what it could be inside the newer app versions?

bambi851

@Tech@ZWO Thanks for the info. Are you planning on updating the app so it looks for other stars and doesn't cross the meridian? I didn't know if I could control this.

Tech@ZWO

bambi851 Currently does not have a plan on it.
Try to find a position that won't cross the meridian after 2 times rotation, then run ASPA.

Tech@ZWO

lucasdanda Could you reproduce the problem and submit the log in the ASIAIR app?
We will analyze it as soon as possible. thanks.

lucasdanda

Tech@ZWO

After a long period, I was finally able to perform the test and report through the Bug Report feature. Can you guys check it, as it is still a problem? Still can't polar align with my ASIAir Mini... It's useless at this point since I have no view of the celestial pole (nor does anyone in the southern hemisphere/low latitude anyways...).

RoscoeD

As a disinterested observer of this thread, you've sorely missed "as soon as possible". This thread is 10 months old.

Tech@ZWO

RoscoeD We will release a new public test version soon, could you test it in that version after release?
Thanks.

SFQbME0I

I have this exact same problem as well. Based in Sydney, Australia, I only have a north facing view of the sky from my balcony (my apartment building obscures to whole south facing aspect) and ASPA would be super useful (in fact I had clear skies and a great view of Andromeda last night but couldn't PA!). Same symptoms - if I just refresh the screen without adjust RA or DEC at all, the values just keep increasing in both directions. Trying to adjust for DEC and RA is a fool's errand.

I have my fingers crossed this issue will be fixed in the beta release - @Tech@ZWO, do you know when this is scheduled to be released?

Thanks.

Tech@ZWO

SFQbME0I Should be released this week.

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