Hello Robert,
I assume that it is not your tool that is to incriminate. Maybe I would have to open a new thread for this topic.
For the test I evoke I just used simulators. And all looks fine, I have the good focal and aperture.
But for this object HD198149 the solver never converge and doesn't move the simulator mount. The object is 61° DE which is far from the North Pole.
I tried to do the same for Alderamin in Cepheus and the result was identical.
I have set the telescope focal and aperture to respectively 777 and 111mm. The camera simulator is 1280x960 pixels of 3,75µm. And all the index files covering the computed field (41.3' x 30.9') are presents (index-4208.fits 2Mass and index-4108.fits Tycho2).

Hum, maybe I am silly or Alzheimer. I guess the CCD simulator cannot change the view of the targeted field. So, the process can enter in infinite loop never finding the good solution. If I am right, I am sorry, this topic is not a good one.
But now I understand the philosophy of your tool and YES the automatic mount model is a great improvement and a really good use of astrometry. I hope to test it very soon. Maybe tonight if the weather remain clement.

From your screenshot, it looks like it did solve the image, but you have told it to "slew to target" and you have the accuracy required to be 15. I think its a simulator issue. I have found that the simulator always has a certain amount of error and a sync does not correct it. I would recommend requiring 30 arcsec instead or setting the align module l to sync only and not "slew to target" so that it can actually complete if you want to test the modeling tool with the simulators. The error in the simulator is nice for testing purposes, but you cannot expect its accuracy to improve like a real mount with a pointing model would (unless the simulator is rewritten).

It shouldn't start the capture until it arrives at the star. do you know the circumstances under which this happens or is it random?

Tested it an hour ago. It works fine on 3 stars in Leo. But as for the first iterations the error is huge the colored target becomes very very tiny. So we have to rescale and pan. It would be better to rescale the target while the points are drawn. Maybe it could exists better solutions.

As far as I see it seems to be random, probably a race condition, but quite easy to reproduce.

The target size is determined by the requested accuracy in the solver at the moment, which you can change whenever you like.

The target appears very tiny because you are very far off target. You can delete any points that you don't want to see anymore.

patdut,

here is a demonstration of what I meant about the built in error in the telescope simulator, a series of 20 solutions spread across the sky using the simulator and the mount modeling tool using a wizard generated grid pattern. I just ran this a few minutes ago. Interestingly, the pattern is slightly different than one I ran the other day. and one point is even outside of my circle, which is interesting too. Since I made this tool, I have run several variations of patterns like this with the simulator and it produces interesting patterns. What I don't actually know is whether the error I am seeing is error in the simulators, error in the astrometry.net files, or if it is a periodic error simulation in INDI CCD, which Jasem suggested it may be.

here's a couple from two days ago

If you see any pattern to when it happens, please let me know. So far, I haven't seen it and I have been running it quite a bit. I have only been using the simulators recently due to a lack of good weather.

Oh, I forgot to post the more scientific and interesting ones I did. Keeping a constant DEC and changing the RA and then keeping a constant RA and changing the DEC. The patterns are much more clear. Note that the wizard cannot generate these points. I had to enter them manually. The reason is because for the constant RA version, you would not really want that because I think most mounts want a change in RA for building their pointing models. For the constant DEC version, you could do part of the circle but not the whole thing due to the fact that most of these points are below the horizon. The simulator is the only thing I know that can image below the horizon.

Now it seems to happen pretty much every time after the first star, log shows rows like this:
2017-03-16T09:32:11 Capturing image...
2017-03-16T09:32:09 Slew complete. Solving Alignment Point. . .
2017-03-16T09:32:09 Slewing to target coordinates: RA (01h 20m 22s) DEC ( 27° 21' 09").

ie. it starts slewing and immediately thinks it's complete even though the telescope simulator has just started slewing taking a few seconds to complete. All I did was connect simulators (telescope and ccd), go to mount model dialog and press generate and start.

For the first star it works correctly:

2017-03-16T09:32:02 Capturing image...
2017-03-16T09:32:00 Slew complete. Solving Alignment Point. . .
2017-03-16T09:31:24 Slewing to target coordinates: RA (15h 43m 27s) DEC ( 26° 14' 36").
2017-03-16T09:31:24 The Mount Model Tool is Starting.

This is Intel i5-6500 quad core machine with indi and kstars compiled from current git, running Ubuntu 16.04.

Edit: I also tried with EQMod simulator instead of telescope simulator and the behavior is the same except EQMod also complains as the mount model is trying to sync the mount while it's still slewing:
2017-03-16T09:48:08 Solver aborted after 4 seconds
2017-03-16T09:48:08 Syncing failed!
2017-03-16T09:48:08 Syncing to RA (17h 38m 51s) DEC ( 16° 54' 19")
2017-03-16T09:48:08 Syncing failed!
2017-03-16T09:48:08 Syncing to RA (17h 38m 51s) DEC ( 16° 54' 19")
2017-03-16T09:48:08 Slewing failed!
2017-03-16T09:48:08 Slewing to target coordinates: RA (15h 43m 27s) DEC ( 26° 14' 36").
2017-03-16T09:48:08 Syncing to RA (17h 38m 51s) DEC ( 16° 54' 19")
2017-03-16T09:48:08 Solution coordinates: RA (17h 38m 51s) DEC ( 16° 54' 19") Telescope Coordinates: RA (00h 38m 16s) DEC ( 87° 55' 37")
2017-03-16T09:48:08 Solver completed in 4 seconds.
2017-03-16T09:48:04 Starting solver...
2017-03-16T09:48:04 Image received.
2017-03-16T09:48:01 Capturing image...
2017-03-16T09:48:00 Slew complete. Solving Alignment Point. . .
2017-03-16T09:48:00 Slewing to target coordinates: RA (00h 00m 09s) DEC ( 6° 57' 28").