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Asiair polar alignment

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#1 SubaruB4

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Posted 05 February 2025 - 12:11 AM

I just got back from a 3 week vacation so I havn'et had time to mess with it after this screen shot but using it with the SAGTI I used a Nikon D700 as the camera however after 2 hours on a beach with temps in the low 20's I gave up.. Not one point did I even get in the center and one tiny adjustment, and I do mean tiny caused the target to shoot off left or right.. I'm not sure if it's the settings causing issues with the Asiair on the camera but it was a bit disappointing.

 

Screenshot-2025-01-09-21-54-20-954-com-z


Edited by SubaruB4, 05 February 2025 - 12:19 AM.


#2 exsomet

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Posted 05 February 2025 - 09:43 AM

I have experienced the same thing with the inconsistent movement when turning the alignment knobs (EQ6-R Pro). I don’t think this is an issue caused by the ASIAir, but rather the mount itself.

The best I can figure out is that it probably comes down to the fact that the alignment mechanism itself (meaning the threads on the knobs, the mechanical parts inside the mount that facilitate adjustment, etc) are imprecise at a certain granularity.

When I align using the polar scope, it isn’t perfect left/right and up/down movement; there is some diagonal motion and there is (for lack of a better term) backlash when changing the direction of adjustment. There’s also very minor, but present, inconsistency between each turn of the knobs sometimes.

All of this works out to mean that absolute perfection is probably more of a headache than it’s worth on polar alignment, especially via the air where you have to adjust blind and then refresh to see how close it got (at least, unless you’re doing longer sub exposures).
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#3 SubaruB4

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Posted 05 February 2025 - 01:14 PM

I have experienced the same thing with the inconsistent movement when turning the alignment knobs (EQ6-R Pro). I don’t think this is an issue caused by the ASIAir, but rather the mount itself.

The best I can figure out is that it probably comes down to the fact that the alignment mechanism itself (meaning the threads on the knobs, the mechanical parts inside the mount that facilitate adjustment, etc) are imprecise at a certain granularity.

When I align using the polar scope, it isn’t perfect left/right and up/down movement; there is some diagonal motion and there is (for lack of a better term) backlash when changing the direction of adjustment. There’s also very minor, but present, inconsistency between each turn of the knobs sometimes.

All of this works out to mean that absolute perfection is probably more of a headache than it’s worth on polar alignment, especially via the air where you have to adjust blind and then refresh to see how close it got (at least, unless you’re doing longer sub exposures).

What did you end up doing to get it to work? I wont even bother to try again anytime soon since the weather is going to be bad for the next few days it seems (snow) but even moving half a millimeter was enough to show the RA axis circle off the whole circle. the numbers and arrows above the total error I assume means the directions I need to move the tracker? To be somewhat close I faced the tracker true north and did the polar alignment, I'm not sure why the Az axis they didn't make it geared maybe it's not something that can be done? I'd like to make it worth my money for the tracker it just feels like a let down at the moment :(



#4 exsomet

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Posted 05 February 2025 - 02:37 PM

What did you end up doing to get it to work? I wont even bother to try again anytime soon since the weather is going to be bad for the next few days it seems (snow) but even moving half a millimeter was enough to show the RA axis circle off the whole circle. the numbers and arrows above the total error I assume means the directions I need to move the tracker? To be somewhat close I faced the tracker true north and did the polar alignment, I'm not sure why the Az axis they didn't make it geared maybe it's not something that can be done? I'd like to make it worth my money for the tracker it just feels like a let down at the moment frown.gif

The technically correct answer is probably that what "works"/"is good enough" depends on what and how you're doing. If the thing you're shooting is closer to the celestial pole, star movement is minimized and so accurate alignment is less important. If you're pointing farther away from the pole, star movement will be greater and so you'll want to get a more accurate polar alignment. The telescope, whether you're auto-guiding, and the mount (in your case, tracker) itself will factor in too.

 

The answer that will keep you from losing all your hair is that there's a point where it's best to just accept the alignment you've got. The ASIAir interface doesn't do a great job of conveying when alignment is bad, good, or great (beyond the smiley face) or when you have gotten as good as is reasonable and should stop trying to improve.

 

The total error I accept depends on how long my sub-exposures are that night. If I'm shooting 120 seconds or less, I can usually get my total error down below 3' within about 2 minutes of starting polar alignment, which is almost always good enough (and better than I would do visually by a wide margin). I'll then spend another 3-4 minutes trying to get it under 1' of error, and if I can great. If not, I just accept it and move on. If I'm doing longer exposures those numbers change to 1' and 30", respectively.

 

As to the arrows - those show how far you'll want to move the tracker, yes. In my experience with the ASIAir, they're a little finicky; there's some diagonal movement that occurs and can nudge one axis when moving the other. That's just the nature of trackers/mounts, and I don't think it represents anything "wrong". 

 

If you're looking for suggestions on how to get past PA and start shooting, here is what I would do:

  1. Set up and get a rough polar alignment visually through the polar scope of the tracker. Use the polar scope illuminator that came with it, and an app on your phone like PS Align Pro to do this part.
  2. Once you're happy with it, shoot a couple of frames and see if you've got streaking. If not, life is good and you can move on to funner things knowing your PA is good enough.
  3. If you want to tinker, use the ASIAir's polar alignment process to check your alignment and see what it says your total error is. Use this to establish a mental baseline and map a number to what you felt was good enough based on your images.
  4. If in the future you want to use the ASIAir, start by getting it within your acceptable range that you found in step #3.
  5. Set a timer and spend 3-4 minutes trying to get it as good as you can, then stop.

I'm very very far from what would be considered an expert in this hobby, so I have no doubt other folks can provide some tips on getting more perfect alignment (and hopefully, correct me if anything I've said here is wrong). But this approach has produced a consistently "good enough" polar alignment for me to shoot up to 300 second sub-exposures with no streaking!

 

Here's another thread with probably much smarter and more experienced people than me talking about polar alignment, if it helps: https://www.cloudyni...star-alignment/




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