Re: Tesco Value Compasses

On 16 Feb, 17:34, GAGS <gags...@xxxxxxxxxxx> wrote:

In the
UK magnetic variation is 3 deg W and I can use this for navigating in
Snowdonia and on the North York Moors.

Many are going to say it makes little differance, but I would
recommend using a variation that is the nearest whole degree for the
area you are in.

In N.Wales I have been using 2 deg W for a couple of years, currently
the variation is circa 2 deg 18 min.

In NorthYorkshire current declination is 3 deg 47 min, so I would use
4 deg.

In Cornwall I would use 1 deg.

If I had to plum for a single UK wide figure, I would use 2 deg.

You can get a prediction of the declination for a date from here;

http://www.ngdc.noaa.gov/seg/geomag/jsp/struts/calcDeclination

These calculations are in relation to true north, and you will need to
account for convergance, the differance between grid north and true
north.

And here you can get the declination for locations in the UK by post
code or Grid ref based on July 2007 figures.

http://www.geomag.bgs.ac.uk/gifs/gma_calc.html
.

Relevant Pages

  • Re: Tesco Value Compasses
    ... Snowdonia and on the North York Moors. ... recommend using a variation that is the nearest whole degree for the ... In NorthYorkshire current declination is 3 deg 47 min, ... This depends on the way in which the map is constructed, that is, ...
    (uk.rec.scouting)
  • Re: Grid North vs True North? Calculating difference?
    ... grid north has nothing to do with magnetic ... True north points towards the geographic north pole. ... Magnetic north points towards the magnetic north pole. ... Here is a link for calculation of magnetic declination at your location: ...
    (sci.geo.satellite-nav)
  • Re: Icy claim that water has memory
    ... The difference between the two is known as compass variation. ... The amount of variation changes by as much as 20 degrees as one circumnavigates the earth. ... There is magnetic variation almost everywhere, because the planetary magnet isn't aligned with the spin axis. ... anywhere near the agonic line you can navigate *without* having to correct for the difference between compass and true north. ...
    (sci.physics)