On Apr 6, 8:56 am, "Peter Dohm" wrote:
"RomeoMike" wrote in message

...





wrote:

Astro navigation, but it's still an angle away from a standard
vector. So different sciences are using the same word with different
meanings.

However, you're of course correct that for magnetic navigation,
declination and variation are the same thing.

http://www.ngdc.noaa.gov/seg/geomag/faqgeom.shtml

Kev

Thanks to you, farr1220, and Peter. I always wondered in the back of my
mind how the term declination came to mean variation. Now I'm ready to
navigate the outer space :-)

Hmmmm. I see that what I have been calling declination is called
inclination on the NOAA site, so I will correct as appropriate.

In view of my recollections of ground school, I believe that it might be
least confusing to continue using the term deviation for the instrument
error as installed, variation for the difference between true and magnetic
north, and inclination for the angle between the lines of force and the
horizontal--leaving the term declination unused.


Yes and then aviators would be in perfect alignment with ocean
naavigators who use variation and deviation. The conversion from true
to compass heading makes a nice nemonic:

timid virgins make dull company

for TRUE (variation) MAGNETIC (deviation) COMPASS

Cheers MC