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Subject: Re: Annual Increase of Variation
daveweilacher@XXX.XXX
Date: Wed Feb 13 2002 - 07:40:53 EST
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 fat 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.
Original Message:
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From: Richard Pinkowitz richpink@XXX.XXX
Date: Tue, 12 Feb 2002 07:41:57 -0500
To: NAVIGATION-L@XXX.XXX
Subject: [NAV-L] Annual Increase of Variation
Everyone:
What is the cause of the "annual" portion of the magnetic variation on
the compass rose?
Although this "annual variation" is listed for my area of the US,
Massachusetts, as about 1' - 3' this has not been recognized in the
"total magnetic variation" in the charts we have used over the past 20
years. At 3' per year we would have seen a 1 degree change in variation
over the past 20 years.
Is this annual variation in a constant direction or does it oscillate?
Answers would be appreciated so that I could respond to the navigation
class.
Rich Pinkowitz
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