NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Navigation News book review on Earth's magnetism.
From: Frank Reed CT
Date: 2005 Oct 10, 02:31 EDT
From: Frank Reed CT
Date: 2005 Oct 10, 02:31 EDT
"Jonkers has taken magnetic information from many European logbooks and sailing directions between 1500 and 1800. One of his observations is that there's a scatter in measurements of magnetic variation, with a standard deviation of about 2.5 degrees." A problem with this sort of analysis, of course, is that it's dependent on knowing the vessel's actual position. Before 1800, that's usually only possible at known landfalls. And for those who haven't seen it: http://www.HstoricalAtlas.com/mag/ -FER 42.0N 87.7W, or 41.4N 72.1W. www.HistoricalAtlas.com/lunars
