>Ed,with respect, I have heard the term declination used all my
>life by those that were in the profession of surveying, navigating,
>etc. I took the time to look it up in Webster's because I was
>puzzled by your (and others) statements that it was not correct.
>Webster's says:
>
>"Angular distance north or south from the celestial equator measured
>along a great circle passing through the celestial poles."
>
>Doesn't that accurately describe what has been talked about?
(No, sorry, but then the deviation is not correct either.)
That is not what is being talked about. The use of declination in
your case is for astronomical purposes--where the position of a
star is defined in terms of declination and right ascension.
This use of declination in the discussed case is for surveying
and navigating and aligning Yagis on Heard Island and is
referenced to the earth's magnetic field, and is the correct term.
The MAGNETIC DECLINATION, called angle D, is the angle between
Geographic North and Magnetic North.
Maybe the flyboys use deviation but the CORRECT term
(Physics and Surveying) IS declination.
BTW The MAGNETIC DIP or INCLINATION, which is the angle I,
measured between the horizontal and the direction taken by a freely
(3D) suspended magnetized needle. At the magnetic N and S poles
the dip is vertical (and at the magnetic equator it is horizontal).
73 John W0UN
ref. Surveying 5th Ed. Bouchard and Moffitt
Principles of Physical Geology 2nd Ed. Holmes
John Brosnahan
La Salle Research Corp.
24115 County Road 40
La Salle, CO 80645 USA
voice 970-284-6602
fax 970-284-0979
email broz@csn.net
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