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INDI Library v1.9.5 Released (08 Mar 2022)

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

How can this be?

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How can this be? was created by Kurt Lanes

I have a problem that showed up and I suspect my Mount. When commanding a slew to a target the bullseye representing the mount position stops short of the target that is centered and tracked in Kstars. Repeating the command to position the mount causes a motion in Dec only parallel to the target but the RA error does not get reduced. If I do a plate solve with slew and sync the Mount converges not on the target but on the position of the mount as indicated in Kstars.

One question I have is that when you do a plate solve where does EKOS get the desired pointing location from? If it is reading the mount for the desired location then the behavior of the plate solve makes sense.

If the time was wrong then I could understand a fixed error in RA however the Dec moves up and down to either side of the target alternating sides with each point command. If it were a time error the mount shouldn’t move after the initial point.

Kurt
6 months 3 weeks ago #76821

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Replied by Jasem Mutlaq on topic How can this be?

Which mount and which driver? Might be a good idea to put your equipment in the signature as well.
Jasem Mutlaq
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6 months 3 weeks ago #76824

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Replied by Alfred on topic How can this be?

I once had a similar problem and it turned out to be a misconfiguration regarding jnow/j2000. Check whether both your mount and Ekos use the same epoch.
6 months 3 weeks ago #76826

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Replied by Kurt Lanes on topic How can this be?

The Mount is an iOptron CEM70EC using the CEM70 driver. I guess I am most surprised that the plate solve solves to the wrong location and closes to less than 30". That would seem funny if the mount couldn't move in RA. I will add my equipment again.

Kurt
6 months 3 weeks ago #76836

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Replied by Kurt Lanes on topic How can this be?

Alfred

Thanks for your suggestion. As near as I can tell the CEM70EC uses J2000. Do you know where I set this in Kstars/EKOS? I've searched some but cannot find it.

Kurt
6 months 3 weeks ago #76878

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Replied by Kurt Lanes on topic How can this be?

Last night I opened the RA and checked all the cables on the CEM70EC. Everything looks fine so I did a goto to  using Kstars and also using the hand controller. The image below is the result of the hand controller goto command.  I also verified the time on the mount agreed with the time on the computer and Kstars. The polar alignment was within 1 arc-minute. You can see in the image below where the mount is pointed and the aim point is Altair 19h 50m 46.99855 +08° 52′ 05.9563″  I did a seek zero with the hand controller after the polar alignment and also tried the encoder calibration that was in the iCommander window. The FOV is about a degree so you can see the the mount is 3-4 degrees off of the aim point.  I did a solve and the plate solver found a couple of hundred arc-sec error which it was happy to correct however this converged on the current position of the mount and not on the target that was put in via the had controller. You can see that the solved location is not Altair. Sending an additional goto command with Kstars resulted in a telescope move to Altair and the subsequent plate solves place the star in the center of the FOV. I did other points during the night and they all missed but. came close. In each case a second command resulted in convergence. At each point a plate solve converged on the actual mount position and not the target. My uneducated guess is that the EKOS software is getting the desired position from the CEM70 and that this position is representative of the actual pointing position of the CEM70EC  but not that of the desired target. Does anyone know if this is where Kstars is getting the location for the solver?. I was running the latest Kstars 3.5.5.2 as I recall.



 

Kurt
Last edit: 6 months 2 weeks ago by Kurt Lanes.
6 months 2 weeks ago #77082
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Replied by Kurt Lanes on topic How can this be?

The problem is back. Last night I commanded a go to to IC 405 and the mount stopped several degrees away and refused to converge after several repeats. I got out of my recliner and went to the mount and commanded using the hand controller and the mount went right there. Tonight was the same story however it converged after 6 or so repoints.
4 months 1 week ago #79185

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