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Magnetic & Grid North

 
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whoisthechallenger
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PostPosted: Thu Jan 27, 2011 6:11 pm    Post subject: Magnetic & Grid North Reply with quote

I'm a little confused.

Please can someone confirm that in 2014 Magnetic and grid North will align, and we'll no longer have to add numbers to a clue's bearings when plotting them on an OS map.

In 2015, the ditty 'ADD to MAG, RID to GRID' will be obsolete - but only for South West England.

Thanks.
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kk
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PostPosted: Thu Jan 27, 2011 8:52 pm    Post subject: Reply with quote

Hmmm don't know about that I thought it was something like a decrease of 0.5* every 5 yrs?
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Colin
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PostPosted: Fri Jan 28, 2011 12:52 pm    Post subject: Reply with quote

I think the magnetic Declination is currently running about 0 9' or .15 Degree's east a year. The current Declination is around 2 51' W or 2.85 Deg.

Hope this helps

Colin
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whoisthechallenger
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PostPosted: Fri Jan 28, 2011 10:13 pm    Post subject: Reply with quote

I don't want to sound like an anorak now!

It didn't help much, but it did settle an argument. Unless you are comparing Magnetic and True North...
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Colin
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PostPosted: Sat Jan 29, 2011 12:17 am    Post subject: Reply with quote

Hi
I was referring to Magnetic and True North.

If you look at your map key it will have Grid north / Magnetic north and True north Declinations. working on the principle of a shift of 0 9' or .15 Degree's east of Magnetic north each year Grid north and magnetic north should be the same around 2019ish

working on the same principle Magnetic and true north should be the same around 2025.


Colin
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The Merry Wives of Lode
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PostPosted: Fri Apr 15, 2011 9:33 am    Post subject: Reply with quote

For what it is worth, the best site I know of for finding out magnetic variation at any time is:

www.magnetic-variation.com
Laughing Rolling Eyes
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Colin
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PostPosted: Fri Apr 15, 2011 10:55 am    Post subject: Reply with quote

Quote:
www.magnetic-variation.com


do you mean http://www.magnetic-declination.com as www.magnetic-variation.com does not seem to exist

Colin
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The Merry Wives of Lode
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PostPosted: Fri Apr 15, 2011 2:05 pm    Post subject: Reply with quote

You are right, I do mean www.magnetic-declination.com.

I appear to have a photographic memory but no film!!

Sorry to any one if i have misled them.

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The Sly Fox
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PostPosted: Sat Apr 16, 2011 6:59 pm    Post subject: Reply with quote

The Merry Wives of Lode wrote:

Sorry to any one if i have misled them.


No problem.
Oh, and welcome to the site
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whoisthechallenger
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PostPosted: Sat Apr 16, 2011 8:09 pm    Post subject: Reply with quote

Well this post runs and runs! Thanks for the website info Sly Fox and Merry Wives Of Lode (and welcome to the forum)! It all seems to support the Ordnance Survey explanation of Magnetic Variation (see http://www.ordnancesurvey.co.uk/oswebsite/aboutus/reports/misc/north.html).

Penzance and the tip of Cornwall will get Magnetic North/Grid North parity in early 2015.

However, it will take up to a further 4 years for such an effect to reach Dartmoor and our clues.
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trekkernod
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PostPosted: Mon May 16, 2011 4:00 pm    Post subject: Reply with quote

Hi,
Regarding the Variation between Grid, True & Magnetic North.
If you have a current issue of the Ordnance Survey Explorer Map No.28 - Dartmoor, and view the South Sheet. My map is Issue B2, not got B3 yet.
In the bottom Left Hand corner you will see the Legend details for the map. On the far Right Hand side of this information box you will see details about the variation of the North's.
On my map, as of July 2010: At the centre of the N & S sheets:
True North is 1*28' and 1*29' east of grid north respectively.
Magnetic North is estimated at 1*28' and 1*25' West of grid north respectively.
Annual change is approximately 09' east.

Hope info helps.
Noddy
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whoisthechallenger
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PostPosted: Wed Jan 22, 2014 4:15 pm    Post subject: Reply with quote

Its in the news, so I thought I'd comment. To quote the article: "in a small area of England west of Penzance, the grid magnetic angle is slightly to the East." For navigation poets out there: 'Grid to mag - get rid. Mag to grid - add.' And that doesn't sound so catchy!

http://www.grough.co.uk/magazine/2014/01/22/eastern-turn-for-compasses-for-first-time-in-200-years-as-north-shifts
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