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question on compass
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Martin Clark
(Marty_Mcfly) - F

Locale: Southeast US
question on compass on 03/19/2013 19:36:46 MDT Print View

Forum members,

i'm looking for a adjustable declination compass for a navigation class I have this weekend. I will also be taking this compass with me on the PCT and want to make sure that I pick the right one.

I was trying to decide between these two:

Suunto M3-Leader:
Suunto MC-2 Pro Compass:

how important is it to have a mirror for accurate sighting?

Thanks in advance!

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: question on compass on 03/19/2013 19:44:27 MDT Print View

I would check with the instructor for the class.

The mirror makes it easier and (usually) more accurate to take a sighting and triangulate your position. IMHO, either one will serve you well for many years.

I like having the mirror for secondary use as an emergency signal, grooming, etc.

Do you know why compasses have a mirror? So you can see who is lost!

Todd T
(texasbb) - F

Locale: Pacific Northwest
Re: question on compass on 03/19/2013 19:50:46 MDT Print View

"how important is it to have a mirror for accurate sighting?"

For the PCT (aka Interstate 2000), I'd say it's unnecessary weight and bulk. In fact, even for most off-trail hiking, it's not really necessary. Most of us are usually looking for things like lakes a quarter mile wide, so the additional accuracy of a mirror is of dubious value. It's a bit different if you're doing lots of resections or looking for geocaches, I suppose. My $0.02

Rob Lee
(roblee) - MLife

Locale: Southern High Plains
Re: question on compass on 03/19/2013 20:03:04 MDT Print View

My experience and corroborated by what I read you can navigate just as accurately using a baseplate at chest level as you can with a mirror at eye level. A mirror adds: a mirror, some level of protection when closed, about $10-$20, signaling device, about 1 ounce. The MC-2PRO adds a clinometer. The Brunton O.S.S. 10, 20, 30 models have no-tool declination adjustments, are cheaper, and lighter. I use a Brunton Classic, removed the mirror cover and love the big dial. Works great

Edited by roblee on 03/19/2013 20:04:30 MDT.

Ian B.

Locale: PNW
Suunto MC 2 on 03/19/2013 20:17:38 MDT Print View

FWIW I'm going through the SAR academy right now and about 2/3 of the class is using the MC-2; there are a couple Bruntons and no U.S. made Silvas. Mirror isn't necessary but I can shoot an azimuth with it with more precision. The markers for our most recent land nav courses were a few inches below the surface of the ground so that level of precision was a must. With my failing eyes, I've come to love the magnifying glass on it. The baseplate is a nice size for plotting grid coordinates. The MC-3 would be my next choice if I were to buy one without a mirror.

The only issue I've run across with it is that the clinometer on my MC-2 was sticking. I was the only person in my class with that problem so I returned it to REI and my new one is perfect. Overall a well loved compass but like anything else in life there will be an occasional dud. Check the needle swing of the compass and clinometer to make sure they swing freely and save yourself a trip back to the store.

I rarely ever use a compass when trail hiking (always bring one though) except to occasionally orient my topo map. 99% of my trail navigation is with terrain association. You can buy a cheaper/lighter compass later for the PCT. I'll always bring my MC 2 or one with a magnifying glass as it is my back up if I break my reading glasses.

Have fun.

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: COMPASSES ARE NOT HEAVY on 03/19/2013 21:03:25 MDT Print View

Compasses in general are not heavy. I really went for broke on bulk and weight and got a Suunto MC-2G. At 2.6oz and the size of an iPod, I don't think it is heavy or bulky, especially considering that I bet my life on it working when I need it!

FYI, point and shoot camera cases are great for a compass case. A freebie eyeglass case works for a baseplate compass.

Suunto MC-2G

Suunto MC-2G

compass on 03/19/2013 21:05:34 MDT Print View

Generally speaking, the compass will weigh less than the map, of which it is nearly useless without.

Christopher Kuzak
US Made Silva on 03/19/2013 21:35:28 MDT Print View

Just got a US made Silva base plate Explorer Pro. It's 1 oz, but quality isn't at the level of Suunto, something I knew going in. It works so far and weighs .6 oz less though.

Ian B.

Locale: PNW
Two zone vs global on 03/19/2013 22:05:33 MDT Print View

Since we're on the topic, I was hoping someone could shed some light on what the difference is between the MC-2G and MC-2D. I understand that the MC-2G is "global" so the needle will work in the southern hemisphere but I'm reading conflicting reports at to what the "D" indicates. One page refers to it as Dual Zone and then explains how it will work in the southern hemisphere as well. There's obviously a distinction between the two but I'm not googling my way to an answer. I snooped around on Suunto's website as well but I didn't find the answer (I'm known for overlooking the obvious on occasion.)

A classmate has a MC-2D and the baseplate shows different markings so maybe it's ideal for some other mapping system beyond UMS, UTM, MGRS?

I just bought the plain ol' MC-2 as that is all they had in our local REI when I was shopping.

Edit I should've checked BPL first!

Edited by IDBLOOM on 03/19/2013 22:08:20 MDT.

Erik Basil

Locale: Atzlan
Get the sighting compass on 03/19/2013 22:11:50 MDT Print View

of those two, I'd suggest the sighting compass. It's easier to shoot a good line for a bearing, heading or triangulation and it's multiuse: it's your mirror.

By the way, sighting compasses can be light and small for the ultralighter. The Brunton Trooper is 23 grams.Brunton Trooper compass

Stu Pendious
(Beeen) - MLife

Locale: California
Re: question on compass on 03/20/2013 11:55:56 MDT Print View

I had both, and kept the MC-2 and gave my dad the M3. Mainly I just like being able to see myself. Especially before hitch hiking to make sure I don't have a streak of soot on my face.

I haven't found any great benefit for taking readings with the mirror, except it becomes moderately more useful in the desert when getting misdirected by mule trails and washes... but I don't think it would be a huge handicap not to have. Maybe if I needed to use a compass more it would be really worth it... but right now, it is just a way to bring a mirror and not have my friends make fun of me.

Sometimes I miss having a more slender compass that I could palm out of my pocket and read in an instant. With the MC-2 it takes a little more effort to bother, and most the time I don't.

Edited by Beeen on 03/20/2013 12:16:06 MDT.

Hamish McHamish
(El_Canyon) - M

Locale: USA
- on 03/20/2013 15:30:20 MDT Print View

Another benefit of the MC2's mirror is that when opened flat it provides a nice longer straightedge for map work, though this is likely not needed if you're sticking to trails and not doing more advanced landnav.

You can also open up the mirror flat and still use the center hold aiming method, you don't have to always sight with the mirror. Do the center hold for a quick easy azimuth check or sight with the mirror for more precision. Versatile.

Even if you stay in North America the Suunto global needle is worth having IMO. It is highly visible, fast dampening, and tolerates a less-than-perfect hold nicely.

David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Less, much less. Or more. But much less for the PCT. on 03/20/2013 15:58:45 MDT Print View

For the course (props to you for taking a course!), get what most everyone else is using. A mirrored, sighting compass is classic, versatile, and with care, any quality compass lasts forever, so I'm teaching my kids on the compasses I myself learned on, 40 years ago.

BUT, for UL BPing on the PCT, I'd bring on a little button compass, something on a zipper-pull, or nothing at all. 90% of the time, I can tell north to 10-15 degrees from the sun, stars, and terrain, and in the remaining cloudy times, there's this well-traveled north-south trail to go by.

For BPing with a little off trail, I'd go for the smallest, lightest mirrored compass in part because the mirror is useful for some self-assessment and first aid at times. Something like:

For geocaching, cave surveying, relocating a fishing hole or butchered carcass, etc; I go with the most accurate small compass I've found, the $160, 108 gram Suunto KB-14 optical sighting compass:

Not cheap, but I can read it, quickly and accurately, to 1/2 degree. The Suunto style is more accurate, lighter and a quarter the price of the $600 Brunton Pocket Transit that EVERY geologist I've ever worked with got for their summer field camp and now proudly owns the worlds most expensive shaving mirror.

Or in plastic by Suunto at $80, 39 grams.

Or a Harbin knock of the aluminum Suunto at $64.

I've never tried the optical Deruite at $38.50. I might get one to play with since I'm planning some scouting skills lessons with the kids (plus friends' kids) this summer.

Stephen Barber
(grampa) - MLife

Locale: SoCal
re: question on compass on 03/20/2013 20:57:47 MDT Print View

Good one on the button compass for PCT and other trail work. I have a button compass mounted on the sternum strap of my pack, and if I'm hiking trails it's all I really need.

On the other hand, I "grew up" hiking following topos with a mirrored compass. If I have any doubt about the route I'm taking, I have a mirrored compass handy because I know I can use and trust it.

Daryl and Daryl
(lyrad1) - MLife

Locale: Pacific Northwest, USA, Earth
Re: Re: question on compass on 03/20/2013 21:55:11 MDT Print View


Thanks for the laugh. I liked it enough to repost it in Chaff.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: question on compass on 03/20/2013 22:08:43 MDT Print View

The first one is perfectly adequate for all navigation, imho.I do not carry anything more complex.

Mirrors - only for secondary functions, like shaving or signalling.


Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Less, much less. Or more. But much less for the PCT. on 03/20/2013 22:39:17 MDT Print View

"BUT, for UL BPing on the PCT, I'd bring on a little button compass, something on a zipper-pull, or nothing at all."

No, no, no, NO, NO, NO. NO!!!!! NO!!!!

I think this is very bad advice. Everyone should have a decent baseplate compass and a map and know how to use them. Period. Button compasses are fine for backup or just general orientation while on the trail. BUT, when you get lost, you need the right tools. In fact of you use the tools right, you won't get lost in the first place.

David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Re: Re: Less, much less. Or more. But much less for the PCT. on 03/20/2013 23:17:58 MDT Print View

CYOC (carry your own compass). Or not.

While I enjoy using quality gear, just because I love using a K&E Decilon or more so a 4080-5 20in Log Log Duplex Trig or a real (RPN) HP calculator, doesn't mean I can't figure things out to 3 or 4 sig figs in my head.

I found I have less use for first aid gear the more I studied first aid and thought of safety, environmental exposures, and infectious issues. Because the more I considered them, the fewer problems I had and the sooner I was treating companions before things got quite so dire.

Likewise, if I keep assessing which way is north, testing my estimate of the time-of-day BEFORE looking at my watch, and try to predict when I reach each trail junction, I never get so disoriented that I'm having to triangulate my position only knowing I'm (hopefully) somewhere on the quad.

I'm glad the OP is taking a class on map & compass. That, and a lot of use in the field on real trips, is a path to both (1) being very competent when you really need to use it and (2) avoiding most all the situations where you really need to use it.

Ian B.

Locale: PNW
Terrain Association on 03/21/2013 00:08:22 MDT Print View

I'm not willing to make the shift away from carrying a quality compass (or carrying a knife) but to be quite honest I rarely use it backpacking/trail hiking. I've never used a button compass so I can't speak to their reliability.

I do 99% of my navigation with just the topo map and only bust out the compass if I've really turned myself around. The more you learn to use catching features and handrails in the field and translate what you see on the map to what you see on the ground, the less often you'll need to orient your map with a compass.

For SAR, military, and surveying applications then a precision instrument is a must but I'd be ok with something which will generally tell me which way north is in pea soup fog. As David mentioned, the higher your skill set the less you need.

BLUF I think the MC2 is a fine compass for the money and I don't mind carrying it even if it's overkill. My only regret is that I didn't order the Global version.

Edited by IDBLOOM on 03/21/2013 00:09:00 MDT.

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
Silva Ranger on 03/21/2013 00:19:32 MDT Print View

I've had a Silva Ranger for decades. The mirror is great for precision and for seeing what foreign object is in your eye (not to mention checking to see if your eyeliner is on OK ;o)

The inclinometer is a must when travelling in avy country in winter.

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.


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.

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 and Angela
(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

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) - M

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

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.


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.