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INDI Library v1.9.7 Released (29 Jul 2022)

Bi-monthly INDI Library released with new drivers and bug fixes.

How to fix that weird calibration process on my iOptron CEM60 ?

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I have a problem that didn't occurs in previous versions of INDI
On my iOptron CEM60 the calibration on the RA axes barely moves the mount. I set the impulsion and the result is the same. And unfortunately the DE axes does larger movements due to this value that I set to 5000.
I wonder if :
1/ This is a problem with the mount that by accident appears at same time as the update of libindi.
2/ There is some issue on the impulse of the RA for this mount.

Seems that the consequence is that there is a very weird guiding with some periodic drift that is compensated by the algorithm afterwards (Proving that this algorithm is very robust.)
Last edit: 1 month 2 weeks ago by Patrick.
1 month 2 weeks ago #85113

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Hi Patrick,

I have a CEM40 and have not noticed any calibration problems like you mention (I have been using the latest indi upgrade with modification to the ASI driver :) . A quick experiment to see if it is related to indi updates is to see if PhD2 shows the same problem. I suspect that it may be mount related. I have had some recent guiding issues related to sudden and repeated loss of guide star SNR. This was related to loss if image from the guide camera which was being routed through the mount USB. Routing through the main camera USB hub resolved the problem.

Cheers
Mike
iOptron CEM40G, SharpStar CF90IIApo with Moonlight focuser, ASI294MCpro, ASI120MM-S, DIY MyFocuserPro2, RPi4 8Gb 480SSD running KStars/Ekos/Indi under Ubuntu Mate 22.04, DIY flat box
Skywatcher Flextube 12" Dob, Meade LX75 8SCT, Skywatcher NEQ6Pro

1 month 2 weeks ago #85115

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Where are you calibrating? It should be meridian, close to DEC zero. If you try to calibrate close to the pole, RA move gets reduced by cosine(DEC).

I'm not calibrating often, as I have a permanent pier and a fixed setup that I just put on it when observing (I think the calibration I use is from last year... :whistle; ) I might re-do it for a test, but ATM I've started imaging already. But guiding has no issues (CEM60EC).
openSUSE Tumbleweed KStars git INDI git
GPDX+EQMOD, CEM60EC, ASI2600/1600/290mini+EFW+EAF
1 month 2 weeks ago #85116

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Peter, I calibrate every session , yesterday I was on Perseus double cluster.
Maybe I am wrong doing calibration each session.
1 month 2 weeks ago #85123

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Hej Patrick,
it's not really 'wrong', and of course depends on your setup. In some cases this is needed.
But if you have your mount controlled by INDI (and thus get the pointing information) it is highly recommended to not calibrate the guider on the target, but (as I noted) somewhere close to meridian/celestial equator. And if your OTA setup including guider is fixed, to re-use the calibration.
In your case, the Perseus double cluster is at roughly 60⁰ declination, so a RA pulse will effectively move only half (cos(60)=0.5) the distance that it would move with the same pulse at celestial equator.
If you prefer to keep calibrating each time at target, you should at least increase the pulse length based on the target declination (at 70 degrees it is already a factor of 1/3)....
openSUSE Tumbleweed KStars git INDI git
GPDX+EQMOD, CEM60EC, ASI2600/1600/290mini+EFW+EAF
1 month 2 weeks ago #85124

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Before describing my problem let says that I have corrected 2 days ago the polar alignment and have now 14" polar alignment error on both axis.
New test last this night.
I selected as target Theta Aquilae close to the celestial equator to maximize calibration movement in RA.
Unfortunately, there is no more improvement. With 5000 as pulse the calibration process moves just a fraction of pixels in RA (on display) and/or does some erratic moves forward/backward in both X and Y. The spot doesn't come back to the origin before starting DEC process.
In autoguiding session the RMS error on RA is between 0,25" to 0,5". Two months ago, calibration process worked differently, my RMS error on RA was between 0,10" to 0,25".
I am not sure that the guiding correction is working while autoguiding.
I tested PHD2 using INDI server for mount and camera autoguider. The calibration always failed on "not enough move on East/West axle".
I am not sure this is a INDI problem, but the only change in 2 months is an update of INDI/Ekos/Kstars and my setup didn't change.
As the movements of the mount on both axles and tracking looks fine I don't understand what the problem is.
Another issue is that the mount parking position is lost between 2 sessions. But this is another problem.
I have 2 guidelogs available separated by 3 months but have some difficulties to interpret them. But guiding process seems to act differently.
Something that seems weird is the focal length displayed in the calibration header.
Last edit: 1 month 2 weeks ago by Patrick.
1 month 2 weeks ago #85150
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This really looks weird. Can you check in the INDI tab of the mount (under Motion Control) what the Guide Rate is set to? It should be 0.5 for both RA and DEC, which would be 7.5"/sec. You seem to only get something in the 0.3"/sec area with your calibration, that would be 0.02 or so. In doubt, verify numbers also with the hand controller.
Also, if you do a calibration, in the same tab do you see the guide pulses as numbers in the Guide N/S and Guide E/W sections?

Other things that irritate me: The mount seems to not report Pier side. Mine does. What driver are you using? Do you guide with an OAG? The log says focal length 800mm, is that correct?
openSUSE Tumbleweed KStars git INDI git
GPDX+EQMOD, CEM60EC, ASI2600/1600/290mini+EFW+EAF
1 month 2 weeks ago #85154

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You are right Peter.
1/ on the hand controller the values of guiding rate were 0.05 and 0.5.
2/ On the motion control tab the values (that were not in the set place values) were 0.01 and 0.10
In both cases, handle controller or INDI, the values ratio are the same.
Once I use together the hand controller and Ekos/INDI maybe there was an unexpected interaction between hand controller and INDI.
Is it a coincidence ?
Unfortunately the guiding rate disappeared from the guiding tab of Ekos, so it is difficult to see that the value is set or no.
On the other hand , maybe the mods of Ekos guiding tab to move them to control panel made an unexpected reset of them.
For the park position lost each time I shut off power, this might have something to do with pier side, but this info doesn't appears neither in the control panel or hand controller.
I am using the Legacy driver. I didn't made a firmware update so I don't use a recent specific driver for CEM60. I am afraid of doing this because of the freeze risk. Maybe I will have to do it very soon.
Thank you Peter your advice was of great value.
Test will be done if the sky is with me.
Last edit: 1 month 2 weeks ago by Patrick.
1 month 2 weeks ago #85163

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Hi Patrick, that is great news I think. I'm quite confident with guide rates set back to 0.5 calibration will work as expected again :)
As you are using the legacy driver w/o pier side info, it might be a good idea to stay with your habit of calibrating the guider at target, and after each slew, as I'm not sure how the 're-use calibration' option works in that case...
Good luck and clear skies for tonight!
openSUSE Tumbleweed KStars git INDI git
GPDX+EQMOD, CEM60EC, ASI2600/1600/290mini+EFW+EAF
1 month 2 weeks ago #85166

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All worked fine. Calibration is perfect using 2500 pulse value and a 0,5x sidereal rate. The result is a RMS error od 0,5 arc seconds which means that the movements around the zero axle are greater than + or - 0,5s. I don't know if the instrument specification in the guiding tab is used by guiding process or only used to compute the error on main instrument level.
1 month 2 weeks ago #85203

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I opened a new topic because the calibration issue I met is not fixed. Seems that this is linked to weird phenomena taking in account and storing the guiding rates for the ioptron legacy.
For the moment I can't guide and my last session failed and I closed my telescope shelter for a while until I find a solution.
www.indilib.org/forum/mounts/12215-recur...acy-driver-ekos.html
4 weeks 5 hours ago #85819

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Hello all,
Desperate by the issues I met with the Legacy driver I have done an upgrade of the firmware on the CEM60. I must admit that I was close to heart attack doing this process. I have done it on many devices but never on a mount. So I was afraid to brick my mount. Hopefully all went good. All seems to work fine and the guiding rates are same on handpad and in mount config.
Two nights ago I have done a session. For the calibration I still have to set the pulse to 4000 to have a significant displacement in RA (I was on Cephee Iris Nebula). That makes me doubtful. On the other hand the pulse value seems to be huge for calibration on DEC axle.
Whatever, the calibration went to finish. I haven't change any parameters on guiding process.
The guiding session have been ugly. In the past, before issues with Legacy driver I was guiding between -0.25 to 0.25 arc sec RMS with low values of plus or minus 0.11 arc second RMS.
Now, the RMS values are pic to pic between -1.5 to 1.5 arc sec and RMS around plus or minus 0,75 arc sec.

Is there some advice concerning the guiding parameters that you can give me to improve the guiding process ?
3 weeks 2 days ago #85993

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