Compass terminology

[AJB]

Hi,

I feel I’ve done this to death, but Stuart (the Mod), suggested I post this thread.

I was asking some questions about Tru-Nord compasses. Then I bought a couple, which were wrongly set and then I opened a whole can of worms regarding terminology, hence Stuart’s suggestion.

I thought:-

Declination was the variance between magnetic north and true/grid north
Inclination was the angle at which the magnetic field subtends the earth’s surface
and
Deviation was local error due to other magnetic fields

However, it appears I’m a Muppet, or a Boffin depending on your point of view. Could someone please make a definitive statement about this terminology.

Ta ever so.

 

[Goose]

http://home.att.net/~agligani/navigation/magnetic.htm

http://www.wide-screen.com/support/FAQsuunto.shtml

I would call declination, variation, but i think the two terms are interchangable.
The two sites above explain it pretty well I think.

 

[Stuart]

declination seems to be one of those incorrect terms that has been used for so long that it is generally excepted.

declination infers a vertical angle, not a horizontal one so Variation wound be a more accurate term.

either way it is really only an academic argument.

both declination and variation are accepted terms for the variance between magnetic north and true/grid north