Hi mstram,
Your "rule of 60" is only an approximation.
The magnetic declination (variation to us in UK) changes all over the world, so you must take account of that change when you move to a different position.
See:
https://www.google.co.uk/search?q=ma...FNsdjb326aw%3D
Last edited by Goldenrivett; 7th Sep 2015 at 08:28.
Reason: declination / variation terms