Historical change in Magnetic Declination over time.

[Clay Lindsey]

Those who treasure hunt should be using maps to plot out the items they find. It is because of this, I am posting the following link. This link will help you find the historical magnetic declination for your area. Simply input your zipcode on the left to convert it to geo coords, then specify the date range on the right. I easily found the adjustments for magnetic north, by decade, from 1800 until 2010 for my area. I hope it helps.

Clay

www.ngdc.noaa.gov/geomagmodels/struts/historicPoint

 

Amazon Forum Fav 👍

DR.ÖTEK Metal Detector, Waterproof Gold Detector, Pinpoint & Terrain Modes, Professional Metal Detector - Grab it through Amazon!

[Old Silver]

Good stuff. Thanks.

 

[Real de Tayopa Tropical Tramp]

Excellent and true data Clay, gracias. I used to do it the hard way.

don Jose de La Mancha

 

[tesoro dog]

DON JOSE!! YOU ARE BACK!!! I WAS WORRIED,, THAT MAYBE YOU WERE IN THE HANDS OF THE FEDERALES!!! AYE CHIHUAHUA! td

 

[stilldign]

Declination will NEVER be a problem when searching for treasure rooms and mines. The people(s) who buried these treasures, no matter which group they were representing, understood perfectly this declination and they made up for this problem. The only real and true problem is that most treasure hunters don't understand how this problem was "dealt with" (in the field). Do you really think that these peoples who buried these treasures, or were coming back to locate these treasures, had access to a phone (or any other resource) where they could call in (or write a letter) and get the declination, thereby allowing them to make the proper adjustments
This web site is great for some problems where declination is truly needed, but it is not needed when locating a treasure room or a mine.

 

[Old Dog]

In some places the declination is as much as 2.5 degree's or more.
When dealing with a great distance ... the farther away from your focal point,
the greater your chances of missing the next sign, or even the "dig here" mark.
Declination is a good thing to have, at least to reference to.

 

[stilldign]

Old Dog,
Like I stated, this declination is dealt with, as long as you know what you are supposed to look for. Even with the "long distance" maps, which lead to a certain point where the treasure map takes over, you are given exact "places" that confirm that you are on the right track.
Declination has no place or "worry" when it comes to locating treasure rooms and/or mines, but if you or anyone else wishes to waste your/their time on this nonsense, then so-be-it.

 

[Clay Lindsey]

I'll revise my statement... If you are using a map consisting of landmarks only, then you will not need to adjust for the change. Only if you are using a map that was made by use of a compass.

Clay

 

[stilldign]

Clay,
Please.....show me just ONE treasure map that uses ONLY compass degrees!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Clay Lindsey]

The first photo in the nothin but drill holes thread.

 

[Clay Lindsey]

And I can prove it.

 

[Clay Lindsey]

In realizing that a lot of people may not know or have known the magnetic pole continues to shift, and therefore not realizing the importance of noting the change, I have added this link which has a neat little animated graphic that shows just how much it shifts and has shifted.

The animation covers the years between 1590 -2010. The follow-on link is located under the first graphic on the page. Thanks for listening.

http://geomag.org/info/declination.html

Clay

 

[Real de Tayopa Tropical Tramp]

Good morning; Declination and variation are very important on maps or directions from the late 1500's to the early 1600's. Also just how they designated the compass points for directions.

In one case I had the compass coordinates to a hidden mine portal. After being hidden it was subject to a few hundred years of storms, hurricanes and normal weathering. There was absolutely nothing visible. Directions like 15 * in the south west quadrant were just not enough.

Their celestial fixes were notably inaccurate since they had no accurate time pieces to measure by except for the usual sun/moon/ etc., rise or zenith for Longitude.. Bowditch and accurate time pieces didn't come along until the 1800's.

Shucks, even in WW-2 we were lucky to hit our position within 1/4 - 1/2 of a mile. Sooo everything helps.

The first trips were unsuccessful, then a major hurricane passed directly over it and finally some of the internal timbering collapsed, partially exposing the portal. It took sheer genius to find it he he he

Don Jose de La Mancha

 

[Bum Luck]

As a land surveyor, let me add to this discussion.

It's of course true that educated folks knew about declination, around 8 degrees here in Wisconsin in the 1850's. So, surveyors (then also engineers) knew about it as well as we know about Google since they used it every day.

The less educated also knew about it, and although they didn't have the nice equipment, they did have practical knowledge, some much more than others. Not like today, though, where it is easier to get by without basic survival skills.

So, how I do it is this way: I put myself in the footsteps (or brain) of the person I'm following as best i can and then see where that gets me. It's, like much else in life, an acquired skill that you can improve with practice.

That will enable you to figure out if they really cared in this particular instance about true north vs magnetic north and their capacity to compute it. Even us surveyors use magnetic north for tie sheets even though we can "shoot the sun" and get astronomic north to within 6 seconds. It's quick and dirty, and the next guy out there will want the same.

 

[Clay Lindsey]

Don Jose!

Always a pleasure to have your input here. You bring to the forefront something that was extremely important. Method...

And as I was typing, Bum Luck, provided more insight...

A new guy like myself knows of the navigational possibilites because I have the latest technology available to help me move through the terrain. However, there is an anthropological aspect left out because I don't have go through the same process as those individuals a century or two or three ago. Having a "Masters" understanding of older navigational equipment would provide far better insight into the thought process of an individual existing hundred's of years ago.

So I'll pose a few questions to the crowd, if you would indulge me. We know they used astrolabes/sextants and compasses, but new guys like myself have little knowledge of the older technology. If someone like myself could better understand the method, we may be able to better understand the sign/symbol and how it was used.

1) What do we know about the types of instruments used to find a particular point on the ground, even at elevation?

2) How were these used in tandem?

3) How would equipment vary by group?

4) How did the answers to the previous three questions effect their travel?

Thank you all for your answers in advance.

Clay

 

[Springfield]

Longitude has primarily been a mariner's concern, not a land-based criteria. Latitude, if neccesary for maps covering a lengthy transit, is easily determined. On land, natural landmarks and artificial permanent control points can be mapped and followed. At the 'end', all you need is a permanent control point and a true azimuth. True north can be determined almost anywhere on earth by a cub scout, and magnetic declination eliminated from time-variable compass readings. This simple technology has been around for millenia.

 

[okey dokey]

BL,
My brother is a historical researcher for a book on man who was a map maker. Just this week he told me that he is totally amazed at how informed the every day guy was about stars and directions. He ran across one fella from the early 1800's that put his property corners in based on the north star. It seems that most people had a working knowlege of stars and directions since they had little else to go on.

Okey Dokey

 

[Clay Lindsey]

Springfield,

How was your vacation? Glad to have you back.

Okey Dokey,

It is for that reason, I asked the question. I am a Nintendo kid from the Super Mario generation. Because of my upbringing and experience in the Army, I can terrain associate really well. But when you add the celestial component, well.... Lets say I wouldn't make a very good sailor from the 1800's. If these traveller's came by sea and used their sea-fairing ways to navigate, I am automatically at a loss. There is no GPS on earth that can push a button and help orient myself to the North Star (not that I know of).

How possible would that be to calculate movement on the ground (small scale = mile or less) by using the stars?

Clay

 

[Springfield]

Springfield,
How was your vacation? Glad to have you back....

Great - went through a tsunami evacuation, some live volcano action and a 4.4 earthquake. Never a dull moment.

....How possible would that be to calculate movement on the ground (small scale = mile or less) by using the stars?

Impossible, IMO.

 

[Clay Lindsey]

Springfield,

I'm jealous... Ok, maybe not of the evacuation, but definately the volcanic activity.

Clay