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Martin Clark
(Marty_Mcfly) - F

Locale: Southeast US
Solid advice on 03/21/2013 04:06:35 MDT Print View

I have expressed this on the PCT-L, but I have a pet peeve with the fact that many people entering the backcountry have very little map and compass experience if any. It's a shame because one would think that people would be hesitant to enter into the woods without learning some sort of navigation skills to ensure that they don't get lost.
I unfortunately was not a scout as a kid and have not acquired those essential back country skills and now as an adult and forced to learn these skills in another way. I will report back on the class for anyone who might want to do something like this in the future as I'm quite excited about this.

I've still not decided what compass, but i will be getting a global compass as I've heard the needle is more stable and I would like to just have one single compass if I ever do hike in the southern hemisphere. The leader of the class has strongly recommended the M-3 Global Pro compass.

Thanks to al who have contributed to this thread.

Edited by Marty_Mcfly on 03/21/2013 04:07:24 MDT.

Nick Gatel
(ngatel) - MLife

Locale: Southern California
Re: question on compass on 03/22/2013 12:16:00 MDT Print View

I don't understand why people want a declination compass. Declination changes over time and a 1 degree error in declination means you have a 100' error per mile. Orient your map to the magnetic north of the compass and then shoot your azimuth.

If you are lost, which shouldn't happen if you have a map and compass with you, then you orient the map to the terrain and shoot two azimuths to recognizable landmarks and draw lines on your map using the edge of the compass. Now you know where you are; you are at the intersection of the two lines.

Military lensatic compasses do not have declination adjustments and soldiers have been navigating unfamiliar terrain for decades using these compasses. Also they are graduated in mils, which is 6,400 mils versus 360 degrees. Accurate to 2 mils. No bubbles; they use a jewel bearing instead of liquid. Work at temperatures from -50F to 150F. Sturdy.

cammenga compass

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: question on compass on 03/22/2013 13:46:16 MDT Print View

Nick, it varies with your locale.

If you move from Southern California to Northern California, you will see the magnetic declination change a lot. If you move from west coast to east coast, you will see it change a lot more. Yes, magnetic declination changes over time, but it is a fairly small amount unless you go up to Hudson Bay or Greenland.

Yes, I used a military lensatic compass when in military training. However, both of those army camps were relatively close to the Midwest where the magnetic declination is very low or else zero. So, it was easy to ignore the declination and get away with it. Once we got to the Far East, the serious land navigators threw away their lensatic compasses and had new backpacker-grade compasses (with declination adjustment) shipped in.

Also, land nav is one thing if you are operating around Palm Springs, but it is a totally different experience if you are operating in the North Woods someplace where the only landmarks you can find are mossy trees.

--B.G.--

Brian Lindahl
(lindahlb) - MLife

Locale: Colorado Rockies
Re: Re: question on compass on 03/22/2013 13:49:38 MDT Print View

For me, it's less about declination, and more about setting bearings. It's still more of a convenience thing, though, but a pretty huge convenience in my experience.

When off-trail hiking through woods, fog, mist or rain (no landmarks), as fast as possible, it's easier for me to keep an arrow centered in another arrow, than it is trying to keep the arrow pointed at a particular number - you have to look down/hesitate more, and end up moving slower as a result. This is especially true when it's dark and you're navigating rugged terrain.

I remember when I summited Mt. Jasper in the Indian Peaks Wilderness via the NE ridge on an after work hike. I miscalculated the time it took, and ended up returning to treeline in the dark. I knew I had to travel on a particular heading to hit a river, and could then follow the river back to a loop hiking trail, which would then take me to the trailhead. I can't imagine moving as fast as I did, by headlamp, around cliffs, down steep gullies, over deadfall, across marshes and small streams, while trying to keep the compass arrow pointed at a particular number, as opposed to keeping the it centered. I would have been a lot slower.

I was late for my dinner date, but I might have completely missed it and been in big trouble if I had to keep a closer eye on the compass.

Again, still a 'convenience' thing, but in my experiences, being able to move quickly isn't always a minor convenience, especially when you're on a deadline. For example, summiting a peak, or crossing a pass, before thunderstorms roll in.

Another lesson learned from that experience, is that when navigating rough terrain, having a lanyard on your compass is really nice - you can quickly drop it and use both hands to get over/around obstacles like deadfall. This is particularly useful in some areas of the Gore range, which has a nasty amount of deadfall in areas (and very few trails).

Edited by lindahlb on 03/22/2013 15:54:32 MDT.

Ian B.
(IDBLOOM) - MLife

Locale: PNW
Re: Re: Re: question on compass on 03/22/2013 14:05:51 MDT Print View

"When off-trail hiking through woods, fog, mist or rain (no landmarks), as fast as possible, it's easier for me to keep an arrow centered in another arrow, than it is trying to keep the arrow pointed at a particular number - you have to look down/hesitate more, and end up moving slower as a result. This is especially true when it's dark and you're navigating rugged terrain."

The military lensetic compass will do the same thing and if you have a real one it has tritium. There are many cheap knock-offs out there and I can’t speak for them. I have both but I'm using the orienteering style now.

Jeremy B.
(requiem) - F

Locale: Northern California
Re: Re: question on compass on 03/22/2013 14:28:31 MDT Print View

Orient your map to the magnetic north of the compass and then shoot your azimuth.

If the map is not sufficiently recent, the map's idea of magnetic north will be different from the compass's idea of magnetic north, and you're back to making an adjustment.

shoot two azimuths to recognizable landmarks and draw lines on your map using the edge of the compass

And if you draw a third line, from a third point, chances are you have a small triangle rather than a point.

I'd only assume a compass is accurate to about 1-2 degrees even if it has markings for additional precision. I believe the spec for the military ones is markings at 20 mils, with a max error of 40 mils (i.e. 2.25 degrees).

Martin Clark
(Marty_Mcfly) - F

Locale: Southeast US
decision made on 03/22/2013 14:28:31 MDT Print View

I believe I'll be skipping the mirror and have decided based off several opinions on picking up the Suunto M3-Global Compass. I feel like this should be sufficient for my needs.

THanks in advance to all who have contributed their knowledge.

If this compass doesn't work out or I need a mirror, I'll just have to return it to REI : )

wiiawiwb wiiawiwb
(wiiawiwb) - F
Declination on 03/22/2013 15:24:57 MDT Print View

I have two Silva Rangers and both have declination adjustments. I'm likely the minority but I never use that feature.

Before I go out, I draw magnetic north lines on my maps. That way when I'm hiking I don't have to add or subtract the declination adjustment.

There's no right, or wrong, only that which is more comfortable.

Rob E
(eatSleepFish)

Locale: Canada
declination scale vs. adjustable on 03/22/2013 16:04:02 MDT Print View

I used to only be interested in compasses with adjustable declinations, but now that I've used the declination scale on a few, it's quite easy, and I prefer it in some instances. For example it allows you to switch between magnetic and geographic bearings without mental gymnastics to ensure you've added (or subtracted) to remove the declination properly without getting the sign mixed up, you can cut the annoying lanyard without being worried about losing the adjustment tool (if applicable), and you don't need to worry about inadvertently changing the tool free declination, which happened to me once while doing a geoscience job, which was quite embarrassing.

I'll be going to South America with the Suunto M3G in a few months, and I'm quite interested to see how it performs.

David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Re: declination scale vs. adjustable on 03/22/2013 17:23:51 MDT Print View

>"I'll be going to South America with the Suunto M3G in a few months, and I'm quite interested to see how it performs."

In Zimbabwe I found the N-S thing more confusing at times than driving on the wrong side or the million-Zim-dollar notes, etc.

What, the sun is in the NORTH at noon? And the analog watch as a compass, I found trickier than I would have expected. after thousands of hiking hours with things being the other way around. . .

Jim Colten
(jcolten)

Locale: MN
Re: declination scale vs. adjustable on 03/22/2013 19:12:08 MDT Print View

In Zimbabwe I found the N-S thing more confusing at times than driving on the wrong side

An acquaintance who moved to the US from Australia reported the same thing ... could never get east/west right because the bleeping sun is the wrong place!

peter vacco
(fluff@inreach.com) - M

Locale: no. california
compass declination on 03/22/2013 21:05:21 MDT Print View

is a novice deal, but one can get dec of the day at yer location by setting most any garmin gps to the "magnetic" (as opposed to "true") option, and this will show you the local declination.
i am not so totally sure how accurate the data is, but it beats to heck the numbers on an old map.

cheers,
v.

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
Declination and imminent pole reversal!! on 03/23/2013 21:36:32 MDT Print View

Nick, don't worry about compasses with declination. Any month now the poles will reverse and we'll all have to rely on our GPSs. (You DO have a GPS, right?)

Yes, Nick, the magnetic apocalypse is coming. We will all get high doses of solar radiation due to the ionosphere thinning with this cataclysmic event.

BUY A GPS AND SPF 100 SUNSCREEN!! BE PREPARED! (Jus' messin with ya Nick ;o)

OTOH, if you are into orienteering and other precision wayfinding activities DO get a compass with declination adjustment. No more mental gymnastics, no more trying to erase old declination lines off your map. Just point and shoot that azimuth.

But "seriousnessly", there IS a magnetic anomaly in the area of the South Atlantic near the Falklans Islands with a large magnetic NORTH area slowly drifting toward southern South America and about this I kid you not. Further it IS causing more solar radiation to hit the earth in that area. I don't understand the meterology about that but it's well documented.