Hello,
Please note , that park position and home position on the cem25p are not the same.
I never managed to understand how parking works with the cem25p, but when I click on park in Ekos, it skews to a position that is very well suited for taking flats.
Not that I'm 100% sure of this, but... Using two separate mount controllers i.e. Ekos and hand controller (HC) for park/unpark is asking for problems. Each of them is using own logic to handle parking position. I don't know about HC but Ekos (actually INDI mount driver) writes park position to .indi/ParkData.xml file located in user's home directory. Now, ask yourself a question - how would Ekos know that you parked your mount with HC? The same as - how would Ekos know that you released RA/DEC clutches and set your mount manually to any arbitrary position? It wouldn't! Except the mount uses encoders so the driver is aware of it's actual physical position. To resolve this issue you must be consistent with your approach - if you use Ekos to control your mount, don't play with HC. The same the other way around.
Again, this is just my understanding how these systems work. Test this approach if you find it reasonable.
That is the reasoning I also applied to it. I only control the mount through Ekos, although all those controls are being routed through the HC. Nonetheless, I have these movement where the mount slews East, not West, during polar alignment, and it also slews 120 degrees, not the 60 degrees it is supposed to. When I then tell it to park itself again, sometimes tries to complete a full circle and I have to stop the movement to prevent it from slamming into the tripod, other times it only moves back 60 degrees. I cannot find a common pattern.
The only thing to get out of this is to return it to the home position, reboot and then reset Park and Home position (which are identical for me, and I reset and save them every time I start up the system).
Only happens with iOptron, never with my Orion Atlas, so it is unlikely that I am doing something weird here.
I would expect Ekos to query the HC especially when using a mount-specific driver. Of course I don't know the mechanics of how the driver talks to the mount or what information it would be able to read.
Does the CEM25 have encoders? I know some mounts do, but I don't know about the CEM25.
+ Does it natively support parking?
++ Yes: Set Park AZ and ALT (from Site Settings Tab), then issue a native park command. The mount should now park like in the HC.
++ No: Covert Park AZ and ALT (Site Settings Tab), to RA/DE (cannot issue AZ/ALT GOTO on an equatorial mount), then issue a GOTO command to these coordinates. Now where this position ends up at probably varies from mount to another.
After Parking/GOTO is complete, tracking is turned off (when using GOTO). Most of these issues are already resolved on higher end models where native parking is supported.