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Joined: May 2020
Posts: 2,638
Campfire Regular
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Campfire Regular
Joined: May 2020
Posts: 2,638 |
Basically 0° here in this part of Tn and Ky 3° is meh..... 30m right at 1 click Intersting how it shifted per those links versus the nad 27 1985 1/2° GM on my FTCKY maps.
Been up to 20° to 30° level planet wide.
Always look at your GM angle and use accordingly.
Have seen many no go,s on EIB and NCO schools day and night land course,s world wide due to danny dumb azz forgetting to convert GM angle.
Sucks to be you Mr. Retest. Own it dumbazz......
Easy to mess up on a land nav course, especially under duress! That's why we train, and I have seen the best of the lot miss a point and have to backtrack and refigure, including me! I messed up at Camp Darby once!
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Joined: Aug 2002
Posts: 19,098
Campfire Ranger
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Campfire Ranger
Joined: Aug 2002
Posts: 19,098 |
7 degrees? So magnetic north is more toward the true north? Seems odd. Back it 2019 we did a star shot off polaris at the Rocky Mountain National Rendezvous. With 18th century equipment. We came up with 7 degrees north at our location. We have a new table table coming especially for the purpose of shooting a star shot proper. Hopefully I will be back with a report on the results. With photos! Bob, I never shot Polaris while working, but we had a crew that did. I did do a lot of sun shots, using an HP calculator to compute the results, but we never compared the results to magnetic North. Later it was all done with GPS. When I first started to work back in the 1960's, out transits had an offset, set in the instrument, but it turns out that they were all over the place with different crews, so we set all of them back to zero, and the correction was applied in the office. It has always been a confusing thing to most people. Kinda like ground and grid coordinates. miles
Look out for number 1, don't step in number 2.
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Joined: Aug 2002
Posts: 37,851
Campfire 'Bwana
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Campfire 'Bwana
Joined: Aug 2002
Posts: 37,851 |
Back before GPS it was 9 degrees East here, now I see it’s it’s 3.86 which we woulda called 4.
Back in the day I used to have to find pieces of old rebar on Camp Bullis, hammered into the ground to mark bird sampling points, laid out in a line, random start and direction, each point 200m apart on the map (actual walking distance varied with terrain.
Tough to find a rusty piece of rebar a foot tall back in the woods, but made much easier by contour lines in that hill country setting. Still, it was lots of practice with pacing and heading.
I found all kinds of stuff dropped or forgotten in training areas, one time a compass, looked to be military issue. I was disappointed to find it had no provision for setting declination.
So I dunno if they were supposed to do the math every time they took a bearing, or else they just gave them headings to use without them having to worry about declination.
"...if the gentlemen of Virginia shall send us a dozen of their sons, we would take great care in their education, instruct them in all we know, and make men of them." Canasatego 1744
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Joined: Dec 2009
Posts: 31,599
Campfire 'Bwana
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Campfire 'Bwana
Joined: Dec 2009
Posts: 31,599 |
Our shot was not 7 degrees north as I stated. It was like 7 degrees east. I don’t know how close it was to actual. This was done at night with a rod and lantern after a bottle or two of Bordeaux.
Last edited by kaywoodie; 09/18/21.
Founder Ancient Order of the 1895 Winchester
"Come, shall we go and kill us venison? And yet it irks me the poor dappled fools, Being native burghers of this desert city, Should in their own confines with forked heads Have their round haunches gored."
WS
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Joined: Jan 2006
Posts: 69,258
Campfire Kahuna
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Campfire Kahuna
Joined: Jan 2006
Posts: 69,258 |
Every military compass I've used had a way to set declination. There are a lot of cheap military knockoffs on the market for as little as $10. You wouldn't want to bet your life on one.
“In a time of deceit telling the truth is a revolutionary act.” ― George Orwell
It's not over when you lose. It's over when you quit.
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Joined: Jun 2006
Posts: 45,996
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2006
Posts: 45,996 |
Source/link for current declination?
Ours here used to be big, but it’s much smaller now, but want current. Even currant.
Are you lost, again?
A wise man is frequently humbled.
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Joined: Dec 2019
Posts: 16,911
Campfire Ranger
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Campfire Ranger
Joined: Dec 2019
Posts: 16,911 |
well I guess the poles flip from time to time... why should anything stay the same on a living planet??
I know that I can set the declination on the electronic compass in my car and most silva type compasses have a means of setting declination...(though I seem to recall that it is not intuitive...
next thing you know we will be hearing about the magnetic shifting crisis on the news..
it certainly allows NOAA to sell more chats...(another source for declination is navigational charts (air or sea and probably topo maps too)
-OMotS
"If memory serves fails me..." Quote: ( unnamed) "been prtty deep in the cooler todaay " Television and radio are most effective when people question little and think even less.
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Joined: Jan 2006
Posts: 69,258
Campfire Kahuna
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Campfire Kahuna
Joined: Jan 2006
Posts: 69,258 |
well I guess the poles flip from time to time... why should anything stay the same on a living planet??
I know that I can set the declination on the electronic compass in my car and most silva type compasses have a means of setting declination...(though I seem to recall that it is not intuitive...
next thing you know we will be hearing about the magnetic shifting crisis on the news..
it certainly allows NOAA to sell more chats...(another source for declination is navigational charts (air or sea and probably topo maps too) From time to time is a long time. The last flip was estimated to have been over 700,000 years ago, a bit before the compass was invented. Everything that they say will happen when it flips is largely speculation as nobody really knows.
“In a time of deceit telling the truth is a revolutionary act.” ― George Orwell
It's not over when you lose. It's over when you quit.
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Joined: Dec 2019
Posts: 16,911
Campfire Ranger
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Campfire Ranger
Joined: Dec 2019
Posts: 16,911 |
well I guess the poles flip from time to time... why should anything stay the same on a living planet??
I know that I can set the declination on the electronic compass in my car and most silva type compasses have a means of setting declination...(though I seem to recall that it is not intuitive...
next thing you know we will be hearing about the magnetic shifting crisis on the news..
it certainly allows NOAA to sell more chats...(another source for declination is navigational charts (air or sea and probably topo maps too) From time to time is a long time. The last flip was estimated to have been over 700,000 years ago, a bit before the compass was invented. Everything that they say will happen when it flips is largely speculation as nobody really knows. that long ago? I remember seeing a chart of flips I think it was tied to oil exploration and dating the rocks that they are drilling....or maybe it was in ice cores in a book about a buried alien space ship... thanks for adusting my frame of reference...
-OMotS
"If memory serves fails me..." Quote: ( unnamed) "been prtty deep in the cooler todaay " Television and radio are most effective when people question little and think even less.
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Joined: Jan 2006
Posts: 69,258
Campfire Kahuna
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Campfire Kahuna
Joined: Jan 2006
Posts: 69,258 |
Here's a diagram of how the north magnetic pole has been moving. I haven't figured this out yet. Here in Idaho, MN is east of TN. Yet, according to this map, it's west of it. Maybe it looks different on a round globe.
“In a time of deceit telling the truth is a revolutionary act.” ― George Orwell
It's not over when you lose. It's over when you quit.
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Joined: Jan 2006
Posts: 69,258
Campfire Kahuna
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Campfire Kahuna
Joined: Jan 2006
Posts: 69,258 |
Then there's the geomagnetic north. I have yet to find a description of what it is written in layman's language. It's not the same as magnetic north and a compass points to MN. However, many of the maps I've seen show GMN for a compass bearing, not MN. I'm lost on this one.
“In a time of deceit telling the truth is a revolutionary act.” ― George Orwell
It's not over when you lose. It's over when you quit.
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Joined: Dec 2003
Posts: 86,134
Campfire Oracle
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OP
Campfire Oracle
Joined: Dec 2003
Posts: 86,134 |
Source/link for current declination?
Ours here used to be big, but it’s much smaller now, but want current. Even currant.
Are you lost, again? Never been lost. 😉
If you take the time it takes, it takes less time. --Pat Parelli
American by birth; Alaskan by choice. --ironbender
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Joined: Jun 2006
Posts: 45,996
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2006
Posts: 45,996 |
Source/link for current declination?
Ours here used to be big, but it’s much smaller now, but want current. Even currant.
Are you lost, again? Never been lost. 😉 Well then, you're not trying hard enough.
A wise man is frequently humbled.
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Joined: Dec 2003
Posts: 86,134
Campfire Oracle
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OP
Campfire Oracle
Joined: Dec 2003
Posts: 86,134 |
There was this one time I briefly did not recognize my surroundings.
If you take the time it takes, it takes less time. --Pat Parelli
American by birth; Alaskan by choice. --ironbender
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