# When calculating magnetic declination...



## xnazzx (21 Feb 2006)

Here's the questions....

What is the magnetic declination for a map dated 1991, with a declination of 6°59' E and a an annual change of 14.6' increasing? 9 calculate using 2004 as the current year)

Here's what I did...

2004 - 1991 = 13
13 x 14.6=  *189.8* now, i forget does it round down to 189 or round up to 190?


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## George Wallace (21 Feb 2006)

xnazzx said:
			
		

> What is the magnetic declination for a map dated 1991, with a declination of 6°59' E and a an annual change of 14.6' increasing? 9 calculate using 2004 as the current year)
> 
> Here's what I did...
> 
> ...


You haven't finished you calculations yet.

You have to convert 189.8' to Degrees 189.8' /60'  =  3 Degrees 13.8 Minutes

Now you add that (as your Declination is Increasing)  to your 6°59' E  to get  10°12.8' E


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## Michael OLeary (21 Feb 2006)

mo-litia said:
			
		

> Just check your GPS.  :dontpanic:



Well, that was helpful. Perhaps if you can't help answer an honest question, you should refrain from posting.



			
				George Wallace said:
			
		

> You haven't finished you calculations yet.
> 
> You have to convert 189.8' to Degrees 189.8' /60'  =  3 Degrees 13.8 Minutes
> 
> Now you add that (as your Declination is Increasing)  to your 6°59' E  to get  10°12.8' E



3 degrees = 180 minutes, therefore:

You have to convert 189.8' to Degrees 189.8' /60'  =  3 Degrees 9.8 Minutes

Now you add that (as your Declination is Increasing)  to your 6°59' E  to get  10°8.8' E

For setting declination on the ranger style compass thats between 10.1 and 10.2 degrees.


You can also try this utility that includes a Declination Calculator (caution, 4 Mb download):

http://regimentalrogue.com/products/UTMCalc.exe


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## xnazzx (21 Feb 2006)

Yeah, guys I wasnt sure if you had to round up or down. I knew the rest of the steps, so I just leave the decimal?


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## George Wallace (21 Feb 2006)

Guess I fail my math.   ;D  Don't know where the 13 came from.


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## ryanmann356 (24 Feb 2006)

yeah its the declination that gets ya.  People say its easy but when ur under pressure during nsce its not  :-[


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