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Subject: Annual Increase of Variation
From: Richard Pinkowitz (richpink@XXX.XXX)
Date: Tue Feb 12 2002 - 07:41:57 EST
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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