Lightest functional compass?

[Robert Blean]

Are these liquid filled? I cannot find anything in their descriptions saying that they are.

[Anonymous]

"Something to get me from Evolution lake over Lamarck Col and back to North lake if that helps ;)"

You shouldn't need a compass for that, Christopher. Seriously.

[Marcel Bak]

Robert – according to my knowledge there is alcohol placed inside to stabilize the needle. Some bubbles appeared around 2000-2500 meters AMSL (i.e. 6500-8000 feet) but later dissolved (no problems up to around 3400 meters (i.e. 11 000 feet), haven't tried on higher places).

Haven't tested the compass during actual winter yet, but freezer was not enough for this device.

[Erik Basil]

Robert, these days, everything but toy compasses are liquid filled. All those described (so far) in this thread are, for example.

If you want an "air filled" that you could carry, search eBay for old Boy Scout/ Girl Scout compasses.

[Hamish McHamish]

Eric said:

"the thing about a compass is that you may not need it most of the time … but when you need it you REALLY need it …"

This.

Most of the time you don't need to apply compass-specific methods. Casual observation and mediocre map skill will usually suffice.

But there can come a time when confident navigation skill can really save the day. And it is at that time you'll be fubared if you don't already own the skill. To extend the .44Mag vs 22LR analogy, it's like waiting to be attacked before you learn to shoot well.

I do landnav for the fun of it, I love it, so I am a very biased commentor. I have worked all the skills and tools, and I do orienteering just to keep the skills honed. Further, I have learned to execute the skills when tired and under time pressure. This has yielded confidence that paid off big time during some cross country hikes. And it is also useful for on-trail hikes in areas that are new to me and the trails are poorly documented or riddled with false tracks.

So: get a liquid filled, clear baseplate compass and learn the basics, including map skills. You can do this for cheap, just stick with Suunto (my personal fav), a made-in-Sweden Silva, or a made-in-USA Brunton. Then when you reach the "know what you don't know" stage, you can play around with the more advanced tools from a position of knowledge, not ignorance.

I want to quote Eric one more time:

"the thing about a compass is that you may not need it most of the time … but when you need it you REALLY need it …"

[Robert Blean]

I just ran across this Seattle Mountaineers page. It details the requirements for a compass suitable for a mountaineering compass, suitable for their map and compass course. It gives a brief explanation for each of the requirements.

I'm not sure of the difference between the Suunto MC-2 Pro that is their second choice and the MC-2 Global which is commonly said to be Suunto's flagship professional level compass (can be found on the Internet for about $50). You might want to look into that. There is also a hemispheric model of the MC-2 — it is a few dollars less expensive and would be fine unless you plan to take the compass well south of the equator.

One nice thing about the Suunto compasses with their global needle is that the global mechanism has the side effect of helping them settle unusually quickly. That bit about the needle on the Pro sometimes being sticky may be out of date — I did read about that on the Internet, but it seemed to be an issue that Suunto has long since fixed. By all means "trust, but verify" but do not let that concern you overly.

The MC-2 Global weighs 74 grams, so it is not minimum weight, but it is a very nice compass.

[Mike M]

I have a Silva Guide that I've been carrying for over 30 years now, I bought it when I was Wilderness Ranger working in the Bob. One of my duties was to document remote campsites on a map, so a sighting compass was necessary (this was pre-GPS days :)). This one doesn't have adj declination, but w/ a little practice it's a piece of cake.

It weighs all of 0.9 oz and does double duty as it has a mirror.

Looks like they still make it.

[Ken Thompson]

That 30 year old Silva was made in Finland. All the Bruntons and Silvas sold in the USA are made in China. Suunto made in Sweden.

The ability to preset the declination is handy.

[Bob Gross]

"One nice thing about the Suunto compasses with their global needle is that the global mechanism has the side effect of helping them settle unusually quickly."

Robert, do you refer to the magnetic dip compensation?

When I first heard of a Northern Hemisphere Compass and a Southern Hemisphere Compass, I could not understand that. After all, there is only one North Magnetic Pole, isn't there? I think a compass aligns along the magnetic lines of flux, not toward one simple spot.

Maybe our Aussie friends can comment on how a Southern compass works in the Northern Hemisphere, or vice versa.

–B.G.–

[Bob Gross]

"The ability to preset the declination is handy."

Ken, for those who operate in areas where the magnetic declination is a lot, like California to Alaska, I agree completely that being able to dial in the declination is kind of nice. There are lots of backpackers around Chicago, and the declination there is almost zero, so they tend to neglect it completely.

Since the OP is in California, it wouldn't be a bad feature, although you still have to remember to dial it in.

Incidentally, my car has a (powered) fluxgate compass built in, and the declination is preset. If I drive the car from California to Chicago, it might get a big declination error started. If I drive the car around in three circles, like in an empty parking lot, it will correct its declination. Now we have to figure out how to build that into a backpacker compass.

–B.G.–

[Ken Thompson]

That northern hemisphere compass will point down inside the case and not rotate freely. You'll notice that in the global needle compasses that the housing with the needle is taller, giving the needle more room to operate.

[Anonymous]

"This 23-gram sighting compass is small, includes phosphorsecent dots that make it easy to use in low light, includes the totally bitchen lapel pin feature and is currently on sale on the intarwebz if you look (as the Brunton). This is an excellent small compass"

Erik,

I just took a look at the Ranger LE specs and did not see a declination adjustment feature mentioned. Does it have this feature?

Thanks,

Tom

[Erik Basil]

Tom,

The little Silva/Brunton has a rotating capsule, but not an internal declination adjustment within that. So, to adjust for declination, it's just the "turn the capsule 14-degrees for the High Sierra" or super-impose a few mag-north lines on your map. Actually, all the compasses I listed are this same way.

With the coupon Sierra Trading had this weekend, the Trooper is under ten bucks.

-Erik

[Robert Blean]

Bob,

"One nice thing about the Suunto compasses with their global needle is that the global mechanism has the side effect of helping them settle unusually quickly."

Robert, do you refer to the magnetic dip compensation?

When I first heard of a Northern Hemisphere Compass and a Southern Hemisphere Compass, I could not understand that. After all, there is only one North Magnetic Pole, isn't there? I think a compass aligns along the magnetic lines of flux, not toward one simple spot.

Maybe our Aussie friends can comment on how a Southern compass works in the Northern Hemisphere, or vice versa.

Check here for a brief explanation of how the Suunto system works. Based on googling around it seems to be unique to them and to be the best one going. Global Needle System

As far as I can see, each of Suunto's global models also has corresponding hemispheric models (good for the intended hemisphere, plus a fair way beyond the equator). I do not know what the technological difference is for the hemispheric models. As far as I can see, they have the same features and weight, but are noticeably cheaper. I would expect them to be fine, unless you expect to use your compass in both hemispheres.

[Robert Blean]

For those who don't know about the global needle business, the issue is that the magnetic force a compass responds to has a vertical component as well as a horizontal component. The amount of the vertical component changes as you move north or south on the earth's surface. If you go too far north or south of the zone your compass is balanced for, the needle will incline enough for one end of it to rub on the compass case, making the needle unreliable and unresponsive.

Compass makers divide the earth into 5 zones. In general, the compass you buy is balanced for the zone you bought it in. You should not assume your compass will be reliable if you take it to another zone. That is, of course, a problem for compass-using folks who travel north and south — and there are more of those folks today than there used to be.

Suunto has technology that allows it to divide the earth into two zones — that's what it uses in its hemispheric compasses. It is easier for both Suunto and their customers to only have to worry about which hemisphere they are in (north or south), especially since the compasses have quite a bit of overlap where they both work well.

Suunto has gone beyond that with their global compasses — those work over the entire earth — as just one zone. (I'm sure there are issues very near the two magnetic poles themselves; fortunately, that's not where most of us go backpacking or expeditioning).

There are a couple of other advantages to Suunto's technology. For one thing, the technology results in a better than normal settling time for the needle — that's always a win. The other thing is that the compass can tolerate being 20 degrees off level. That means the compass will work better while you are walking, for example. I would also expect that to mean it may be a better compass for use in watercraft, such as a canoe (think huge Canadian lakes with hundreds of islands).

The above is what I found when I used Google recently — I do not have domain expertise personally. If you want more information, try Google yourself, and report back to the rest of us what you find. :))

[Erik Basil]

I have two Suunto compasses with the global needle in them. It's a cool feature, even if I am unlikely to travel far enough to "really need it".

I would note a couple of things for general purposes:

–Suunto doesn't have an UL compass with the global needle. Only Heavy Ones. The DP-65 "matchbox" might be the smallest/lightest (and is a great instrument), but it's heavier and more expensive than the lighter compasses discussed above.

–You can make your own global needle in those situations where magnetism is pulling your needle askew: level the compass body to the needle. Now, if you're working on a flat table, this might be a pain in the neck. However, if you're in the field, this is super-easy and you've already done it every time you've used the compass at arm's length or the palm of your hand.

–If you're after the lightest compass you can use both on a paper map and to take/set bearing/headings well, your best choices won't include some great utility features available in heavier units. Screw-set declination, Suunto's global needle and inclinometers won't be in the lightest of the full-function compasses.

[Hamish McHamish]

This quibbling talk about baseplate compass weights is silly. Go on a diet, lose 4 ounces off your gut, then get the compass that suits your needs. Sheesh…

By the way, the compass u choose should be a Suunto with the global needle… ;)

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