I had to laugh at this serious research study, which was looking at human ability to detect magnetic lines of force. While some humans can subconsciously detect shifts in magnetic fields, it was the statement about dogs which was fascinating. It seems the family pet orients itself along the north/south lines of force when it does a poo!
So if you have lost your compass just setup your mount to align with the direction your Dog faces when doing it's business (allowing for doggy declination of course).
https://www.gizmodo.com.au/2019/03/f...etic-field/amp