NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Variation of compass
From: Dave Weilacher
Date: 2002 Oct 3, 10:38 -0700
From: Dave Weilacher
Date: 2002 Oct 3, 10:38 -0700
Actually it was intuitively obvious to the most casual observer; right after I'd pressed the send button. On Thu, 3 Oct 2002 13:25:22 -0400 Michael Wescottwrote: > daveweilacher@EARTHLINK.NET said: > > One thing I attempted was to compute compass > variation by assuming a > > GP for the mag north pole of 82N x 108W then > doing a sight reduction > > to obtain azimuth (Zn). > > > Ended up deciding there were two problems > with this; both biggies. > > > First, it ignores the earths own magnetic > anomolies. No help for this. > > > Second, it gives me an initial great circle > bearing when I suspect > > what I'm really after is a rhumbline bearing. > > Great circle is what you want, much the same as > a fix on a radio beacon. > > -- > Mike Wescott > Wescott_Mike@EMC.COM > Dave Weilacher .US Coast Guard licensed captain . #889968 .ASA certified sailing and celestial . navigation instructor #990800 .IBM AS400 RPG contract programmer