Celestial North v Magnetic North ?

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gfletcher
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Celestial North v Magnetic North ?

Post by gfletcher »

Hi Guys

Is there a formula for determining the difference in degrees and minutes between Celestial North and Magnetic North dependant upon where you live ?

Graham
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David Frydman
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Post by David Frydman »

The magnetic pole wanders continually. It is time dependent, although these differences may not be significant, depending what accuracy you need.
I think the runway at Heathrow chenged from 28 to 27, i.e. 280 degrees to 270.
Recently Stansted changed I think from from 05 to 04.
They did not physically move, the magnetic deviation changed, so the compass headings changed just slipping over the mid point of 5 degrees out of ten.
You can find the magnetic deviation approx from web sites for your town but you must at least put in 2011 as the year.
Regards, David
LeoLion
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Post by LeoLion »

This site should 'cut the mustard' for what you want http://www.threelittlemaids.co.uk/magdec/index1.html . The OSmaps show the variation on them too.
I'm old fashioned enough to regard my GPS as an auxiliary device and not a mainstay for hill walking survival :D
Cliff
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Post by Cliff »

Dear LeoLion
Thanks for the pointer to that interesting site.
I must admit I was embarassed not very long ago when someone asked me the necessary adjustment for "real" north relative to "magnetic north". I quoted the first thing that came into my head which had been applicable many years before when I was a keen hillgoer myself.
I must admit to even worse embarassment on two occasions long ago when I was on the hills in bad weather - I actually insisted our compass was pointing in the wrong direction. Luckily I was out-voted by my companions and I wasn't quite daft enough to wander off relying on my own assessment.
GPS didn't exist in my hill-going days. I don't like my wifes "satnav" it seems to take longer to set up than time it might save driving.
Arguably though having GPS when I made my above compass fau-pas might have comfirmed to my satisfaction our compass was right and I was up the creek.
So like you I'll give GPS the nod as a useful but not essential auxillary.
Best wishes from Cliff
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