magnetic deviation

GTB_an_Owl (Geoff) · #1 17-02-2007, 01:37 PM

want to check the magnetic deviation of your location ?

http://www.ngdc.noaa.gov/seg/geomag/...F4EB00BA047312

iceman (Mike) · #2 17-07-2008, 07:12 AM

That page has now moved to:
http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp

They call it Magnetic Declination.

Same thing

gmbfilter (Geoff) · #3 17-07-2008, 07:28 AM

How deviated can an astro owl be?

JimmyH155 · #4 17-07-2008, 05:23 PM

It should be called magnetic VARIATION. Deviation is a term used to find out how the compass is affected by say a ship being made of lots of steel. Before a ship departed on a voyage (I did this on an Aircraft Carrier) the ship would head out to a quiet part of the harbour, and we would "swing the compass" using the services of a couple of tugs. meaning turning the ship round 360 degrees, and noting the magnetic "deviation" This information you would put into the deviation card which would be kept close to the compass. To find your true course, you would use the Magnetic variation (as published on every chart) and then you would consult your deviation card to see what other adjustments you had to make. Easy EH???

gbeal · #5 17-07-2008, 05:30 PM

Yep, I concur, variation, not deviation.

Peter Ward · #6 17-07-2008, 05:55 PM

As I use this every day I go to work, I can concur with JimmyH...magnetic variation is the term....plus the old navigator's maxim:

Variation east, compass least, variation west compass best.

I also had a *very* old compass (now given to my son) that originally was my great great grandfathers (who was a Clipper ship Captain)....inscribed on the back: East or West, home is best

h0ughy (David) · #7 18-07-2008, 10:06 AM

http://www.ga.gov.au/oracle/geomag/agrfform.jsp try this for the real Aussie experience!!

h0ughy (David) · #8 18-07-2008, 10:07 AM

http://www.ga.gov.au/image_cache/GA5826.jpg or this

iceman (Mike) · #9 18-07-2008, 10:15 AM

Nice one Dave!

gbeal · #10 18-07-2008, 11:12 AM

Quote:

Originally Posted by Peter Ward

As I use this every day I go to work, I can concur with JimmyH...magnetic variation is the term....plus the old navigator's maxim:

Variation east, compass least, variation west compass best.

I also had a *very* old compass (now given to my son) that originally was my great great grandfathers (who was a Clipper ship Captain)....inscribed on the back: East or West, home is best

I could be wrong, and don't want to sound like I am teaching some how to suck eggs here, but the way I recalled it was" Variation East Magnetic least" etc.
Deviation relates to the compass, not the actual location on the ground.
Gary