Bug 496975

SUMMARY
Set Up : Using a OnStep mount 
In INDI control panel, mount is configured like this : Autoflip : OFF (defaut); Preferred Pier side : EAST (tested with WEST also, same problem); Minutes past meridian E/W: 10/10.
Those settings works fine for Meridian Flip (MF) south of north pole (NP).

Although MF works fine when crossing meridian south of NP, it does not happen when crossing meridian in between North horizon and NP.

STEPS TO REPRODUCE
1.  Start Kstars/Ekos and connect your devices.
2. setup MF in Ekos mount tab ( exemple: MF if HA>0 degre)
3. Point to an object that is north, below NP and close to meridian, in *west* hemisphere (in this area meridian is crossed from west to east)
4. Wait for countdown until MF to reach zero.

OBSERVED RESULT

First, before even reaching time for MF, we can highligh two little inconsistencies in Ekos Guide Tab:
1 - It says "Pier Side : East (pointing West). But actually, in this specific region of the sky, mount pier is West to point West and East to point East...
2 - for this area, it's not "Flip if HA>x degre", It should rather be "Flip if HA > 12 hours - 4x
(Like if you set Flip if HA>1 degree. In this north section of meridian, you want "Flip if HA > 11h 56m 00s" 
But I notice that when i put 1 degree, count down target 4 minutes east of meridian ( HA = -11h 56m 00s). 
It seem to try MF at HA = -12h 00m 00s + 4x =  -11h 56m 00s ( for x=1 degree). But as we come from WEST instead of EAST, reversing the sign may fix the problem : So that condition become "Flip at HA > 12h 00 00 - 4X" )

Then, when count comes to zero, console says "Meridian flip running"..., but nothing happen, and the mount get stuck with tracking stopped.

Note : when we try the same experiment with a Mount Simulator, the simulated mount does perform the flip. Is it a bug specific to OnStep mout and it's parameter ? Or would it occur in any real mount ? I don't know.


EXPECTED RESULT
Perform MF and track circumpolar object in east hemisphere.

SOFTWARE/OS VERSIONS
Windows: 
macOS: Big Sur
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 
KDE Plasma Version: 
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.13 

ADDITIONAL INFORMATION
- The same issue arized in NIMA years ago and is discussed here:
https://www.cloudynights.com/topic/746613-nina-meridian-flips-fail-north-of-polaris/
Seems they have fixed it since then.

- It is not critical at all for me. I don't even see this sky zone from my BY... ;-) Just trying to help to improve this great piece of software. Maybe it is more a burden for people living north of Finland...