Center and rotate plate solve

I have the following sequence.

What happens are the following steps. The telescope slews to the location and does a plate solve. If there is an offset it corrects the telescope location but it does not care about the rotation. It takes another frame and verifies the new location with a plate solve, again without looking at the rotation. It then simply tells the rotator to rotate to the desired angle without verifying the correct rotation after the rotator stopped. Why does it not first slew and rotate, and then plate solve verifies the center and the rotation?

You have it set to use the Mechanical Angle of the rotator, which is independent of the sky. If you’re looking for a particular sky angle, tell it to use the Sky Angle instead. Then when you do a slew/center/rotate it will adjust the rotator to whatever mechanical angle gives you the desired sky angle.


If I set it to sky angle the rotator does not rotate at all.This is what I tried before but I had to change it to mechanical for the rotator to rotate. If I change the settings to SLEW to location (without CENTER) then the telescope slews and rotates and after the rotation it checks the rotation but not the center.

I am having a similar issue, in that the plate solve and center is not validating the rotator position.

did you ever get this resolved ?


Nothing has happened and Im desperatly waiting for a fix.

Sorry, I honestly do not understand the issue here. Every iteration of the centering routine considers both location and angle

No it does not.
If you select mechanical angle the centering routine totally ignores rotation. I have sent about a thousand examples to you and Kevin. After the platesolve finished the SGP status line shows rotating to the mechanical angle but does not verify the correct rotation.

You may be right… Tbh, I often just glance at and ignore most of your posts because they are often rude, combative and condescending. I am only human and I just don’t want to deal with them.

That said, I will take a look and see if I can find anything…

Thanks. I am not a native speaker and I apologize.

@dloy, how do you think SGP can validate a mechanical angle? SGP tells the rotator to rotate to, e.g., 0 degrees mechanical. The only thing SGP can do is verify the ASCOM rotation command succeeded. There is no need for SGP to check after each slew, unlike when using Sky angle.

I would like to use “sky angle” in SGP but when I select “sky angle” the rotator does not rotate and plate solve nevers succeeds. I tried to summarize the current behavior of SGP with sky angle and mechanical angle in a setup with the Planewave IRF90 rotator.