Re: Annual Increase of Variation
Subject: Re: Annual Increase of Variation
From: Brian Whatcott (inet@XXX.XXX)
Date: Wed Feb 13 2002 - 08:12:47 EST
At 06:40 AM 2/13/02, Dave Weilacher wrote:
>It is my understanding that the magnetic north pole lives at somewhere
>around 75 north by 95 west; this being the area that most compasses point
>to. (except french ones I'm told).
>
>The "pole" is moving west approx 1 degree of longitude per
>year. Longitude where we are is pretty far compared to 75 north plus a 1
>degree change in longitude that far away makes for a very small great
>circle correction to us.
>
>I would still like to know if there is a geographical position of the pole
>that I could use to reduce a variation.
I have seen a chart showing the irregular loops that describe the long term
locus of the north magnetic pole. I understand the US mapping authority
provides a new chart of isogonals each ten years. I suppose that if you
look at the northern confluence of the isogonals on a current chart of this
kind, you have the best estimate of the magnetic pole as of the date of
publication.
Brian Whatcott
Altus OK Eureka!
