It seems you have to be careful what kind of "case" you have on your Ipad if you expect to use the Compass mode in Skysafari or any app.
I struggled for a number of days trying to get Skysafari 6 pro working properly on my new Ipad Pro in the Compass mode.
Never had any issues with my old Ipad.
Problem is my new Ipad case has a magnet in it. NOT GOOD.
This plays havoc with any app that tries to use a magnetic compass.
So do not use a Ipad case with a magnet in it.
regards
Steve