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INDI Library v1.8.5 Released (19 Apr 2020)

April 2020 release of INDI Library v1.8.5 introduces new drivers while providing fixes and improvements to existing devices and core framework.

Improving guiding performance

1 year 9 months ago
PK
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Improving guiding performance #29795
Can anyone share a link or explains how I can use the data revealed during auto-guiding, to adjust the guiding settings to improve performance?

Thanks!

PK


iOptron CEM25P
William Optics Star71
ASI 1600Mm Pro
Moonlight motorfocus
LodeStar X2 and ZWO OAG
DewBuster
NANO PC-T4

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1 year 9 months ago
kengs
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Improving guiding performance #29799
Its a bit of a dark art. The aim of guiding is to correct the periodic error in RA and any drift on both axes. The problem is that it is obfuscated by the seeing which is broad spectrum. What you want to avoid is "chasing the seeing". This is basically when you correct for deviations in the guide star caused by seeing. It doesn't help your images because the seeing is not correlated across the field of view. So correcting seeing deviations on the guide star could lead to worse results on other parts of the image.
Adjusting the guiding parameters should be done mainly to differentiate between the long period mount and drift errors from the shorter period seeing.
Now lets say you can perfectly guide out all the drift and PE and your mount is otherwise free of issues like cable drag, sinking tripod, random vibrations, backlash etc.. What you see then on the guide graph is the seeing which can vary rapidly and randomly and cannot be guided out.
But of course no mount is perfect and you can get much better improvements from addressing those mechanical issues which are also difficult/impossible to guide out due to their randomness. For this you can use the guiding data to help diagnose your mechanical issues.

Ubuntu 16.04 AMD64 VM, RPi3 Ubuntu Mate 16.04, Windows 10 AMD64, Ubuntu 16.04 AAEON UP Core
Avalon M-Uno, EQ6 Pro, Atik420, ASI1600MM-C, ASI120MM-S, DBK21AU04, ZWO EFW, Optec TCFSi
Vixen R150S, GSO RC8, ST80
The following user(s) said Thank You Herrhausen, Blueshawk

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1 year 9 months ago
wvreeven
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Improving guiding performance #29800
Added to this excellent reply: in order to try and minimise seeing effects you at least would want to use 2x2 binning for the guide images. This also helps Ekos to find the center of the star PSF since the light will be more concentrated. Next don't use too short exposure times. If you use 1 sec or less then you'll be chasing the seeing. You'll need to experiment to see what works best for you but I'd advise to use at least 2 sec exposures.

FYI I use 2x2 binning and 2 sec exposures and leave all other settings to their defaults and I get 1" RMS or better on my belt-modded HEQ5-Pro using a 50 mm guide scope with F=160 mm and an ASI120MC-S guide cam. Using the same settings I get 0.7" or better on the same mount or on my EQ6-R using a 60 mm guide scope with F=280 mm and an ASI120MC-S. I tried longer exposures but that showed no improvement and often even a degradation.

Just my $0.02 :)

ASI6200 and filter wheel with a SkyWatcher Esprit 80 ED on a SkyWatcher HEQ5-Pro
ASI1600MM-Pro Cooled and filter wheel with an 8" TS Ritchey-Chrétien on a SkyWatcher EQ6-R
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1 year 9 months ago
PK
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Improving guiding performance #29801
Thanks, good info.
Can someone explain the definition of the various data numbers and how adjusting the proportional and integral gains effect the guiding?
PK


iOptron CEM25P
William Optics Star71
ASI 1600Mm Pro
Moonlight motorfocus
LodeStar X2 and ZWO OAG
DewBuster
NANO PC-T4

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1 year 9 months ago
fenriques
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Improving guiding performance #29802
there was a post by Jasem that pointed to some documentation and give a brief description of the theory behind it:
www.indilib.org/forum/ekos/3083-internal...ment-parameters.html

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1 year 9 months ago 1 year 9 months ago by ElevatedG.
ElevatedG
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Improving guiding performance #29821
The 2s exposure is a good start as mentioned above. Also, experiment with adjusting the min pulse. It seems with my EQ6-R, there are those smaller pulses that were ignored and the mount would continue to be off in a random direction, and finally it would deviate enough that a larger pulse would send the plot closer to center. I ended up adjusting the minimum pulse to 50ms, and have been very satisfied with the outcome. Another problem I was having was a longer recovery on dithers (never had this problem before 2.9.4 update). Increasing the gain has helped, I've left it at 1.0 for now. I may increase this if the issue gets worse. This seems to be a more aggressive way to get the mount back to center if smaller pulses aren't effective enough over a period of time. (someone correct me if I'm wrong) I have the Stellarvue F50 guidescope along with an ASI290mini camera (50mm, 210mm focal length, 2.85"/pixel) My guiding has gone from 0.7 to the 0.4-0.5 range since changing default settings.

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