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On Apr 5, 5:33 pm, RomeoMike wrote:
DR wrote:

Declination in navigation is actually

something else but I'll let you googgle for it.

I'm not sure that's really true. In aviation we talk about variation,
but when I'm using 7.5' topo maps on the ground, declination is the term
used for the difference
between magnetic and true north. (See the bottom left of a US DOI
Geologic Survey 7.5' topo.)
Variation and declination are defined the same
If there's a more sophisticated use of the word declination in
navigation, I'm willing to be enlightened.

OK, it's celestial Nav. Stars are located by declination (angle from
the celestial equator) and RA. The geographical use of declination to
describe variation is the result of bad education propagating a
specilaized technical term into incorrect use IMHO. As I think about
it, how could a word derived from "decline" be related to horizontal
angle...?

Cheers MC

Declination also applies to the earth's magnetic field, and can be measured
and charted. However, its use generally involves an earth inductor compass.
(BTW, Lindberg apparently had one installed on the Spirit of St Louis; but I
don't know whether he ever commented on the ease of use in what obviously
qualified as a light aircraft.)

Peter