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Background

I bought my compass in the US last year. Next week I'm going to travel to Australia.

Question

  • Is my US-compass compatible with Australia? or do I need a special compass?
  • Do I need an adapter?
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4 Answers 4

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I double checked a couple of websites (thanks a lot for the comments to the question) and I'm sure that my compass is not compatible with Australia.

As a result of these magnetic variances, the compass industry has divided the earth into 5 "zones", as identified in the map which shows the different zones starting with Zone 1 at the top and ending with Zone 5 at the bottom (Australia and New Zealand only). All of the standard compasses sold at New Zealand are balanced for Zone 5.

A typical feature for regular compasses is that they can function without problems only at limited longitudes because the changes in the magnetic field affect the position of the needle. For fast needles, this phenomenon is even more prominent.

Source: MapWorld

As well Wikipedia suggests that my compass is not working in Australia:

Because the Earth's magnetic field's inclination and intensity vary at different latitudes, compasses are often balanced during manufacture so that the dial or needle will be level, eliminating needle drag which can give inaccurate readings. Most manufacturers balance their compass needles for one of five zones, ranging from zone 1, covering most of the Northern Hemisphere, to zone 5 covering Australia and the southern oceans. This individual zone balancing prevents excessive dipping of one end of the needle which can cause the compass card to stick and give false readings.

Source: Wikipedia

Therefore the answer is:

  • Compasses purchased in Europe or the US cannot be used in Australia.
  • There are models available with a "world needle" which work around the world.
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    The compass will still work, it may just need to be calibrated or held differently.
    – curiousdannii
    Commented Feb 11, 2017 at 0:41
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    It seems to me, based on the links that you cite, that "cannot be used" is a bit of an overstatement. If you're using a compass calibrated for a different zone, you may need to tilt it appropriately to let the needle rotate freely, but with a hand-held compass (without a built-in spirit level or anything) that's something that you'll need to eyeball anyway. You may still want to get a locally calibrated compass, or one with a "world needle", for convenience, but the one you brought with you from home should still be usable in a pinch.
    – Ilmari Karonen
    Commented Feb 11, 2017 at 1:17
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Having used my Europe compass in America as well as in Australia, I would say you do not need a new one.

It will still point one end of the needle to the north and the other to the south, only the south pole is closer to you than when you are home.

Edit
As pointed out in the comments and the other answers, the direction as given is good enough for casual use, not for situations in which your life may depend on it. Hand held compasses are more likely suitable, mounted ones as in sailboats and planes may not work well enough.

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    it turns out this isn't right; see the answer posted by the OP
    – Andy
    Commented Feb 11, 2017 at 0:00
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    @Andy AFAIK this answer is right, provided that you don't care for absolute precision. The OP is overstating the "cannot be used". It should be: "can be used, but they will not be as precise as when they are used in the zone for which the compass is calibrated". If you care for absolute precision, then you need a properly calibrated compass, if you only care to know the North direction plus or minus a few degrees, any compass will be pretty much fine.
    – Bakuriu
    Commented Feb 11, 2017 at 7:36
  • Andy - this answer is completely right. People have been using compasses round the world for ages. I have only the one compass and it has worked everywhere.
    – Rory Alsop ♦
    Commented Feb 12, 2017 at 7:57
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While it is true that the magnetic field encompassing the Earth is not a sphere and dips inward at the poles, there is no reason a standard compass would not tell you which way is south and which way is north. While doing a google search for compass zones and which one to use for where, I got an astounding number of results for GPS calibration and pretty much nothing for standard analog compasses. There was one(1) sailing forum [www.cruisersforum.com] in which a user mentioned the need of "zoned" compasses for travelling below the equator. In one post. Thats it. If the need for "zoned" compasses were real, there would be a lot more information available on the internet.

If the worry is getting completely lost in the blue mountains or similar, I would think bringing a good map, gps, x-tra batt., compass, and a good working knowledge of orienteering would be paramount.

I have to agree with Willeke on this one, he's got experience. Both Sources given by the OP in his answer are from the same website, "mapworld.com" The wikipedia source cites mapworld as the source for that info. Mapworld is a RETAILER OF COMPASSES IN AUSTRALIA AND NEW ZEALAND.

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    Zoned compasses are definitely "real." Look at the compass manufacturers' websites, not the retailers! This is a more serious issue for sailing or flying, when the compass is mounted in gimbals and is automatically leveled, whatever the attitude of the boat or plane happens to be (even in a gentle turn, a plane's wings might be rolled at 30 degrees to the horizon, and you want the compass to be accurate while you are actually turning, so you know when to fly straight again!) But for a simple compass for hiking, just hold the compass so the needle swings freely, and you will be fine.
    – alephzero
    Commented Feb 11, 2017 at 3:57
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    @alephzero Are you thinking that manufacturers have no financial interest in selling more compasses?
    – user2338816
    Commented Feb 11, 2017 at 12:43
  • I think this argument is a conspiracy theory - the market of people who are going to travel to more than one of these "zones" (and therefore who would be "tricked" into buying two compasses that they don't need) is too small for this to make sense as a means of selling more compasses.
    – Random832
    Commented Feb 11, 2017 at 21:27
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The effect that might make a compass not work in two different regions of the world is called (magnetic) declination. This is due to geometry (geographical and magnetic north are not the same) and local effects on the worlds magnetic field.

A compass might be adjustable to this. Usually there is a little screw, with which you can turn the scale to adjust for the declination angle. Any decent regional map has this declination value marked on it or you can find it online.

For US and Australia the declination does not have to, but can vary a lot. This map showing the declination shows that the declination in the west of the US and in the east of Australia are pretty similar. So to answer the question whether you need a different compass you need to disclose the declination of your compass and more precise locations than US and Australia.

As far as I know there is no such thing as adapters for this. That would be something like an additional scale to mount on top of a compass - not very practical. But maybe someone had an ingenious idea and put it on the market proving me wrong in this - I doubt it.

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    The problem the other answers address seems to be vertical angle of the magnetic field (the inclination or "dip") rather than the declination. Declination will simply cause it to point in the wrong direction can be corrected for by referring to a map (why these maps exist), whereas dip causes mechanical problems with the compass.
    – Random832
    Commented Feb 11, 2017 at 21:19
  • @Random832 Thanks for the hint, I never thought inclination was a problem. I just assumed the force would be so small that there wouldn't be any negative effects. Apparently there is.
    – imsodin
    Commented Feb 11, 2017 at 21:54

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