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Thread: Compasses

  1. #1
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    Default Compasses

    Silly question but a friend of mine tells me that a UK compass doesnt work correctly in NZ and will point in the wrong direction ! Apparently we need one calibrated in NZ ? Just wondered if this is correct as we intend doing some tramping in the near future
    cheers
    Gazza1000

  2. #2
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    As far as I know North is North is North

    However there may well be a difference in the magnetic variation that'll you have to consider. We didn't bring one and bought a GPS out here with built in compass

  3. #3
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    This looks like a decent answer to me!

    http://answers.yahoo.com/question/in...2160034AA7nY8T

  4. #4
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    Thanks very much
    Obviuosly he was pulling my leg and I was too stupid to realise !
    Gazza1000

  5. #5
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    It depends on how accurate you want the compass to be. If it is a cheap hiking-type compass that doesn't have calibration settings then you won't need to do anything as accuracy isn't too important.

    On the other hand if it is a decent boating-type then you'll need to recalibrate it as True North is in a different position compared to Magnetic North from here. This type of compass needs recalibration every couple of years so you'll know if you have one of these! :-)

  6. #6
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    This site explains the problem fairly well.
    http://casanovasadventures.com/catal...pass/p1408.htm
    (Ignore the spelling and grammar!!)
    "Because horizontal and vertical magnetic pull from the earth's magnetic field varies considerably in different locations around the world, a compass needle that balances perfect in North America will drag or stick in the capsule when in South America."

    or this...
    http://en.wikipedia.org/wiki/Compass#Compass_balancing
    "Because the Earth's magnetic field's inclination and intensity vary at different latitudes, compasses are often balanced during manufacture. 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 balancing prevents excessive dipping of one end of the needle which can cause the compass card to stick and give false readings."

    I use a different compass in NZ than in North America. The difference is pretty obvious when they're laid side-by-side.

    Cheers

  7. #7
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    Quote Originally Posted by benandclare View Post
    As far as I know North is North is North

    However there may well be a difference in the magnetic variation that'll you have to consider. We didn't bring one and bought a GPS out here with built in compass
    Except when the magnetic poles flip polarity, then North becomes South and vice versa. However, it only ever does this every few thousand years...

  8. #8
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    Quote Originally Posted by Ramo View Post
    Except when the magnetic poles flip polarity, then North becomes South and vice versa. However, it only ever does this every few thousand years...
    Isn't the next time it's supposed to flip within the next couple of hundred years?

  9. #9
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    Quote Originally Posted by dilanium View Post
    Isn't the next time it's supposed to flip within the next couple of hundred years?
    Maybe, but the process is so random and hard to predict it's like trying to work out when an earthquake or volcano erupting is going to happen. I guess by then everyone will have converted to GPS on their watches or something.

  10. #10
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    Certainly your compass will work in NZ, you just need to be aware of the adjustment for True North to Magnetic North which is very much different to the UK. I think it's currently 20 degrees E of North.

    GPS wise, NZ use a different system for the map grids, and their current system is due to change again in Sept of this year. If you've an old GPS you might find it doesn't display the NZ grids (my old one didn't) and will just display Lat and Long.

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