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North (nevermore)

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Subject: North (nevermore)
From: (John Brosnahan)
Date: Wed, 08 Jan 1997 18:03:48 -0600
Hi, Stu--

You have declination defined in the astronomical sense as is used
with right ascension.  This OPTICAL use is for astronomers and 

But declination is also used in the MAGNETIC field sense and is and
was used to mean the offset between true north and magnetic north 
by physicists and surveyors for centuries before aviators defined it 
differently!  (And astronomers also use declination in the magnetic 
sense for true/magnetic offset as well.)

The science community and the surveyors (and surveying is what we
are talking about--not air navigation) has always used declination 
to mean what the aviators now call variation.  

Too many sources to quote--but look in any physics text, any 
astronomy text, any physical geology text or any surveyors text--
everybody agrees except for the pilots!  (And, again, we are 
talking surveying!)

73  John  W0UN

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