DTG: Declination Check Time

Explained.

25 responses to “DTG: Declination Check Time

  1. lastmanstanding

    No thanks. No offense. Have a compass, no gps, no apps just wits.

    Another “click” to another site. Didn’t look, probably a gub site.

    Take enough walks where there are no roads, no trails, no sidewalks, lots of elevation change and you’ll figure this out on your own. Or not.

    • How does one determine declination changes by walking?

      Details please.

      • lastmanstanding

        Should have mentioned walks in your AO off the beaten path. Most aren’t going to get dumped into unfamiliar territory. If you have to bail and you don’t know your hood/turf, it will suck to be you. City folk, should know how to get out of town without the use of a compass in multiple ways.

        We learned how to navigate woods/mountains early in life and have always seemed to have a built in compass. I’ve spent most of my life outside and just pay attention to the ebb and flow of the earth. Land marks, creeks, rivers, sun rises in east, sets in west, etc. I do it wherever I go. That stuff hardly ever changes. Throw in a snow storm and that can really be disorienting.

        I fully get the compass thing. I have a beautiful Cammenga 3H, I know how to use it. Sometimes I practice.

        I just know where I live, the terrain and am not leaving…under any circumstance Everyone else should also know there backyard. 99% of Americans can’t go 100 miles from home without using MapQuest.

        Again, no offense to anyone but if you haven’t got out of Dodge yet, or made serious arrangements to stay, a compass won’t save your ass. Bugging out on foot is a 1 in a million chance of survival.

    • JohnnyParatrooper

      This is quite possibly the dumbest thing I have read all day.

      How in the actual fuck do you plan to move out 20 miles with out a compass?

      Just so you know, If you do not use a compass, you will make a full loop back to your original position.

      • lastmanstanding

        If you’d get the fuck out of Baltimore and move to a place with mountains, terrain, valleys, creeks, land marks, etc. you would figure it out in a couple days. I will admit, you flatlanders have it far more difficult.

        I’m not dissing the use of a compass. I’m just saying that as a kid growing up, we humped/hunted/fished all over the mountains of NC Pennsylvania and I never once took a compass or got too lost. Same here in Big Sky country. Why, because we were taught to “payafuckintention” to every step we took and we had better be able to retrace it, circumvent it, wtfever it to gtf back to the rig, camp, home…whatever…or get your ass handed to you.

        We were taught to remain calm and rest if confused. We carried kit to spend the night if necessary and we did. No big deal. You get 2 givens every day. Sun rise and sun set. The more time you spend out, you get the feel of how the planet works. Lots of answer to questions if you can control your brain

        Oh, I made a few loops and more tangents than I care to admit but where I live now, I’m confident in my abilities to move about in my hood and will get from point A to point B when I need to. I won’t be moving far, I’m not bugging out anywhere.

      • Sad to say, it was not near as dumb as seeing you type, in another post’s reply, “Ft Sumpter.” That place in Charleston Harbor is called Ft Sumter. Reason being that you won that contest, is that the person you were responding to did not lay out his argument real well in his initial post, and he’s since refined his argument.

        It is hard to refine Ft Sumpter, As Yogi Berra used to say, “You can look it up.”

        You are absolutely right in saying that it is man’s general tendency to circle, while traipsing cross-country un-aided by compass. There is a reason when navigating to a desired point, to build in offset against a barrier, then handrail that barrier back (hopefully) not so far to the desired point. Man does not even follow a compass bearing well, thus the reason to build an offset.

        We Boomers rely on your upcoming generation to get things right. Best way of putting out your argument, is to make sure that its words are spelled right.

  2. JohnnyParatrooper

    Magnetic Declination should be factored into every azimuth.

    You also need three Compasses, and you need to check the difference between the readings on all three compasses.

    Select the one that is the most accurate FOR YOUR AREA, and use that one as your primary compass.

    The accuracy of all three compasses can change depending on where you are. Avoid having ANY iron materials near you.

    The steel barrel of your rifle can affect the accuracy of a compass.

    Mark the difference on the back of your compasses and remember to adjust for this.

    Also, If you ever give someone a compass, and do not inform them of these differences, You will NEVER find them ever again without the use of dead reckoning. So always have a known point selected as your secondary location.

    • lastmanstanding

      I rest my case.

      • JohnnyParatrooper

        You WILL loop back onto your original location.

        Standard land nav’ in basic training is to prove to every private that not using a compass will return you to your EXACT location.

        Man has developed a gait that brings them right back home.

        You need a compass.

        I looped back to within 50 feet of my starting location. I could even seen my foot prints. And that was day time. Night time is even worse.

    • Interesting tip on compass accuracy and marking. Question: What are you measuring the accuracy of the compass you’re marking against?

      In my experience, the model/brand of compass usually indicates how accurate the degree readings will be, and if your compass is declination adjustable, you can factor in adjustments from a prepared declination sheet (homemade or otherwise). It’s one of the reasons I prefer the SUUNTO MC3G, pictured in the original post. VERY accurate as far as inexpensive compasses go – 2 degrees or less, which suits me. My issue lensatic is accurate to within 1 degree, but the SUUNTO is faster to set and can be used directly on the map to plot azimuths without conversion. The only advantages the USGI has over the SUUNTO is the bezel ring and tritium/H3 radioactive glow forever internal light.

      Anyone having a compass needs to have a back up. Just makes sense. As I’m paranoid about equipment, I have 2 MC3’s – one around my neck and the other in my accessory pouch. I also have a Marbles ‘pocket compass’ made of brass as a last resort back up. So, I guess that makes three.

      As always, YMMV.

  3. You can also use aviation maps to find the magnetic variation in your area > http://c-aviation.net/magnetic-variation/ Bang in a local airport to this site and see the sectional chart. http://vfrmap.com/?type=vfrc&lat=27.909&lon=-82.686&zoom=10 Check for the dotted line running just off the coast with an adjustment of (5 degrees W). Zoom out until you see the variation indicator.

  4. For those of you who failed Land Nav (Second Lieutenants? as the joke goes) Declination is not about GPS or websites or cell phone apps.
    Its about calibrating your compass for your AO.
    The magnetic field of the earth (you know that thing that makes the needle on a compass point North?) well, its not constant and that means the needle on the compass does not always point EXACTLY to Magnetic North.
    As you can see from the sample that Pete pulled for our neck of the woods magnetic North is off by 5 degrees and some change. Its going to be different for your AO.
    Now if I am only walking a couple of clicks in the woods 5 degrees is not that much to worry about because I can use terrain association, handrails and backstops to keep me on track. If I am trying to move 20 or 30 miles in the back country then 5 degrees is enough to take me a mile or more away from my intended destination. It matters and if you dont understand why it matters then you should go back and brush up on that part of the course.
    I recommend that you head over to the site for ESEE knives. They have a fantastic Land Nav course that is downloadable as a PDF. While you are there maybe pick up a knife or two since they are also damn good at those.

  5. lastmanstanding

    FFS, all this talk about meat space and everybody navigates with the exact thing they bitch about…more tech.

    Look around your home terrain that God gave you and learn how to get around it without getting lost. It’s that simple.

    • I get your point about walking the terrain, but a compass is about as low tech as you can get.

  6. It is simple, boys and girls.

    1. Don’t use a man which DOESN’T have the magnetic declination in its marginal info.

    2. Grid to Magnetic = RALS = Right Add, Left Subtract
    Magnetic to Grid = LARS = Left Add Right Subtract

    3. Pace count, pace count, pace count.

    4. Learn to terrain associate.

    5. Orient your map to the ground. Keep it that way.

    Initially, learn to orienteer (Land Navigation has always seemed like an oxymoronic expression) in open terrain. Rolling prairie land or hilly desert works well for this purpose.

    Visualize the roll of the terrain from what is illustrated on the map, and vice versa. Learn to read the lay of the land, even when the contour lines on the map were spaced hundreds of meters apart. When I was a private, and an FO, the line dogs, even the PL, were always amazed that I knew where I was in the Swamps of Ft. Stewart. (Oh! And watch of alligators!)

  7. This all has to do with converting magnetic to grid and grid to magnetic azimuths. The former is for plotting your map coordinates and directions, the latter for converting the grid azimuth determined on the map to a magnetic azimuth you can use to make the trek. Any declination diagram indicated of 3 degrees or more variance, plus or minus, should be converted. The formula is: Mag to Grid westerly, subtract the degrees. Grid to Mag westerly, add. Mag to Grid easterly, add, Grid to Mag, easterly, subtract. OR———Easterly MG+, GM- Westerly MG- GM+.

  8. Having a good handheld GPS, with altitude and magnetic card compass, is something everyone should have. I’ve aimed my weather station sensors with one, set up my exact elevation in order to aim ham radio beam antennas, and more. Mine is an out of production Garmin GPSMap 76CX, works great.
    http://static.garmin.com/pumac/GPSMAP76Cx_OwnersManual.pdf

  9. Alfred E. Neuman

    Reblogged this on FOR GOD AND COUNTRY.

  10. I have been on this earth for some time and have noticed the changes in magnetic declination on the compass. Just as I have noticed the declination in societal values, but that’s a rant that won’t get writ, it’s just something that has happened.

    A small goal, is to live long enough that my AO’s location will have zero degrees declination. That may not occur, but declination here gets less year by year. And at the start of my life, the declination was significant.

    Here’s a nugget for land nav trivia fans: navigating at night by Polaris, is prone to up to half a degree error, depending on time of night. Polaris is at true north only when the pointer stars of Ursis Major point either up or down, perpendicular to Polaris. Just thought you’d like to know.