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INDI Library v1.9.9 Released (30 Nov 2022)

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What means always for resetting guiding calibration

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When analyzing a recently reported problem with guiding it seems to me that the expectations what should happen when the option “Always reset guiding calibration” and the current implementation diverge.

Currently “always” means after a meridian flip. I’m quite sure that this is wrong, but does it mean
  1. each time the pier side changes
  2. each time when a new target is addressed
  3. each slew of the mount, even during alignment

I personally would prefer option 1 - which is the most complicated to implement. What are your thoughts?

Cheers
Wolfgang
TSA-120 + FSQ-85 + ONTC 10"F4 Newton + epsilon-160 | Avalon Linear + M-zero | ASI 1600mm pro + 6200mm pro | KStars/INDI on Raspberry Pi 4/Intel NUC
Last edit: 3 years 2 months ago by Wolfgang Reissenberger.
3 years 2 months ago #46091

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I would prefer both 1 and 2 because shouldn't the guiding calibration be redone when an object at a different declination is selected? This, at least, is how I understood the "Always reset guiding calibration" is supposed to work.


Wouter
Wouter van Reeven

ASI6200MM and 7 slot 2" filter wheel with a SkyWatcher Esprit 80 ED on a SkyWatcher HEQ5-Pro
ASI1600MM-Pro Cooled and 5 slot 1.25" filter wheel with an 8" TS Ritchey-Chrétien on a SkyWatcher EQ6-R
3 years 2 months ago #46093

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I agree with Wouter.

The combination of 1 and 2 would take care of all variables that could affect optimal guiding.

Better to calibrate one time too many than one time too few.

Jo
Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set
3 years 2 months ago #46094

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Hi
I don't use the EKOS guider because of the number of calibrations that are necessary. So...
...make it like PHD2?
The calibration is flipped after a side_of_pier change and allowances made for different targets according to DEC.
One calibration is reused over and over and can be reloaded between sessions.

If I were using EKOS though, I'd ask for 1 and 2.
HTH and clear skies.
kubuntu 22.04
700d, eq6, 120mm. Yes, the old one.
3 years 2 months ago #46095

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It doesn't really take that long to calibrate. Less than 1 min. I set the number of steps to 3 and I usually expose in 1 s intervals. If you iterate 5 steps and expose for 5s intervals, then, yes, that would indeed take a lot longer.

I prefer the internal guider. Usually, that works like a charm for me, and is far less complicated than patching in PhD2. The less can go wrong when running a multi-target schedule unattended through the night, the better.
Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set
3 years 2 months ago #46097

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Why are so many calibrations needed?

The correction for declination should be able to be calculated.
The correction for pier side can be determined by doing calibrations on both sides of the pier and once the effect of a pier side change has been determined this can be applied to future calibrations. It should be no more than reversing the Ra correction direction, the Dec correction direction, or both.

Even for a portable set up all that should be needed is a calibration at the start of the evening to determine the camera rotation.
3 years 2 months ago #46098

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I agree, in theory. However, in practice guiding often breaks down after switching to another target. I think that might have to do at least partly with changes in weight distribution, inherent frictions in the mount and cable drag. Those parameters cannot be calculated. Recalibrating in that case restores guiding accuracy.

I also don't know how difficult your solution would be to implement given the current code. Wolfgang would be able to weigh in on that.

In the end I don't care one way or the other, as long as guiding works reliably, reproducibly and accurately and there is a way to fix it, short of rebooting everything, if it goes awry.
Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set
Last edit: 3 years 2 months ago by Jose Corazon.
3 years 2 months ago #46099

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Why should I re-calibrate once declination has changed? As far as I understand it, during calibration the orientation of the camera is being detected. Unless the camera has moved there shouldn't be any reason to do it again, no?

Whoops! Your messages were posted while I was typing mine.
Last edit: 3 years 2 months ago by Alfred.
3 years 2 months ago #46100

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Just a small clarification: my question was, what is expected if the option was selected and not whether this behaviour should be mandatory.

I personally have very good experience in the combination of EKOS and PHD2 and never had problems with calibrations once calculated. I even re-use calibrations over several nights as long as I am sure that I did not rotate the camera and changed the scope.

But there are several out there that need such re-calibrations. And for those, I would like to set the option such that it makes most sense for them.
TSA-120 + FSQ-85 + ONTC 10"F4 Newton + epsilon-160 | Avalon Linear + M-zero | ASI 1600mm pro + 6200mm pro | KStars/INDI on Raspberry Pi 4/Intel NUC
3 years 2 months ago #46104

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Hello folks,
I implemented option 2 - which was quite easy. You can test it here .

Thanks for your quick response!

Wolfgang
TSA-120 + FSQ-85 + ONTC 10"F4 Newton + epsilon-160 | Avalon Linear + M-zero | ASI 1600mm pro + 6200mm pro | KStars/INDI on Raspberry Pi 4/Intel NUC
The following user(s) said Thank You: Ray Wells
3 years 2 months ago #46114

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You're right, back to the task at hand. My thoughts:

1) "What is expected"? Well, "always" is pretty clear. The normal expectation would be 3.
2) Would that be reasonable and helpful though? No. I agree with Wouter and Jo, 1+2 would be the proper solution. And "always" should be changed to something that doesn't raise wrong expectations. But then,
3) since I would never use this option, don't pay much attention to my opinion.

P.S.: "2 only" is good enough! IMO it doesn't make sense to put that much effort into implementing something that I deem a negligible detail.
Last edit: 3 years 2 months ago by Alfred.
3 years 2 months ago #46115

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With all due respect, it is not a negligible detail if your imaging is dependent upon the scheduler. I agree, if you sit next to your scope, or rather are awake to control the flip and can manually erase the calibration and restart it if necessary, then this becomes a negligible detail. But for those of us who are putting the scope out in the backyard and letting it acquire images fully automatically, it really is an essential feature.

Thanks Wolfgang for putting in the effort! Will test as soon as there is a clear night again.

Jo
Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set
Last edit: 3 years 2 months ago by Jose Corazon.
3 years 2 months ago #46121

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