NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Northern Limits of Magnetic Compass Usefulness
From: Tony Oz
Date: 2019 Feb 6, 12:34 -0800
From: Tony Oz
Date: 2019 Feb 6, 12:34 -0800
Frank, there is no need to tilt the gnomon at all - far more important is to have a good shape of the shadow. The accuracy - provided it is not LAN±1hour is better than ±5°. Having the scale not too small - ±1° is very possible. May I repeat: the key is the quality of the shadow - not just a tip of a rod, one needs something symmetrical and round so that the center could be estimated more clearly.
The only drawback is you need to print a new scale each couple of days (near equinoxes). Near solstices - less frequent than that. And make it for your latitude, of course!
Regards,
Tony
60°N 30°E
