Author Topic: Annual western change. Declination  (Read 1004 times)

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Offline Orbean

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Annual western change. Declination
« on: September 03, 2016, 04:48:46 PM »
I was reading Finding Your Way in the Outdoors, a neat book covering wilderness navigation and weather. The book states that annual western change, the agonic line is moving at an annual rate of seven minutes a year. Nowhere else have I run into this before and have read a good amount on wilderness navigation.

Can someone direct me towards more info on this or explain more about it.  Thanks
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Offline Quenchcrack

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Offline Orbean

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Re: Annual western change. Declination
« Reply #2 on: September 03, 2016, 05:45:13 PM »
Quench thanks for the link, it tells me what I have already read, so the guy the wrote the book unfortunately most likely pull his conclusions from the that area when the good Lord split him. NOAA are the experts.
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Offline Dano

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Re: Annual western change. Declination
« Reply #3 on: September 03, 2016, 05:45:58 PM »
Here is a map of the history of magnetic change since the 1500's   https://maps.ngdc.noaa.gov/viewers/historical_declination/   It gives an explanation of declination, and allows you to click on a specific line and see the changes.

There is also a map of the US with moving lines, but I can't find the link I had saved to it.  It's pretty cool so actually see the change in a specific area.

Offline Dano

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Re: Annual western change. Declination
« Reply #4 on: September 03, 2016, 05:52:28 PM »
This one is pretty cool too.  It allows you to enter the zip code of your home area, or a place where you intend to travel, and it will give you the magnetic declination specifically to that location.

http://www.ngdc.noaa.gov/geomag-web/

It's handy because you will usually get really old maps that have not been updated, even when the copy date shows only a few years old.  They sometimes give you a declination arrow, but the angle shown is not always accurate.  It's more just to illustrate if the declination is east or west.  The angle given was only good when it was actually first printed.  This link saves you the hassle of having to do the math and recalculate the change.

Not that I'm lazy or anything like that....... :-[

Offline Orbean

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Re: Annual western change. Declination
« Reply #5 on: September 03, 2016, 06:00:04 PM »
Dano thank you for the link I bookmarked it.
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Offline wolfy

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Re: Annual western change. Declination
« Reply #6 on: September 03, 2016, 08:46:35 PM »
I've put a lot of compass, map and navigation links in this section, so if you do some searches or just browse the pages for them you will stumble into threads like this one.....

http://bladesandbushlore.com/index.php?topic=7916.0   O:-)

EDIT:  :-[    I didn't read all the posts (obviously) or I would have seen Dan's post, but the point remains.  There is a LOT of previously posted navigational aids here in this section of B&B.....most of the links, I have tried to keep updated when they die or become non-workable.

As a side note, I won't need to mess with adjusting for declination if I live for approximately 30 more years.   The 7 second westward advance of the agonic line will put it right over my house! :banana:

Orbean, you probably haven't seen this method for finding your local variation or declination either, but it's a good one to know if you have no access to the Internet.....

http://bladesandbushlore.com/index.php?topic=3299.msg56182#msg56182
« Last Edit: September 03, 2016, 09:03:19 PM by wolfy »
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