black bear
Member
COMPASS DIP
This will be of interest only to the people that travel to locations around the world, and are in need of using a compass to get their bearings.
I first encountered compass dip, many years ago, in a trip to Bariloche, Argentina. I was there to fly-fish for trout in the Nahuel Huapi Lake and climb the Cerros Tronador, Catedral and Lopez.
I took my regular base plate compass, which I had used extensively in North America, and I found there that the needle was sticking to the card providing false readings.
I was baffled until my guide explained that most climbers from the states had compasses that stick and that I needed a compass with the needle balanced for the area. In my compass, the pull from the forces of the magnetic north made the south end of the needle dip and stick to the card.
I found later that when compasses are made, they are balanced for the zone that they are going to be sold, and that the manufacturers have indentified 5 zones of dip.
MAP OF THE FIVE ZONES
Compasses sold in North America are adjusted for the zone one, and where I was in Argentina was considered zone four. Compasses sold over there by the sporting good stores where adjusted for that zone.
If you have opportunity to travel to Australia, you will be in zone five and the dip of the needle will be even more pronounced.
ENTER THE GLOBAL NEEDLE
Suunto has come out with a couple of traveler’s compasses with a global needle. Brunton has at least one in their line and maybe other manufacturers are doing the same.
This is a needle that is optimized to be use in all places (that is why they are called Global compasses). Brunton is making the 8096 AR (a racing compass) with the global needle, and it makes sense as the runners don’t have to stop and level the compass perfectly to take readings as the global needle can work with even a 20 degree tilt.
Climbers can benefit from a global needle as they have more latitude to take a reading from a peak that is too close, as sometimes bearings have to be taken using the imaginary center line of a mountain instead of a peak when using the regular compasses, as the tilt upward will ground the regular needle. With the global needle the chances that you can still use the peak for your target are increased if the angle is less than 20 degrees.
So we should welcome the development of the Global needle and hope that more choices will be made available in the different models of compasses.
All the best
Black Bear
This will be of interest only to the people that travel to locations around the world, and are in need of using a compass to get their bearings.
I first encountered compass dip, many years ago, in a trip to Bariloche, Argentina. I was there to fly-fish for trout in the Nahuel Huapi Lake and climb the Cerros Tronador, Catedral and Lopez.
I took my regular base plate compass, which I had used extensively in North America, and I found there that the needle was sticking to the card providing false readings.
I was baffled until my guide explained that most climbers from the states had compasses that stick and that I needed a compass with the needle balanced for the area. In my compass, the pull from the forces of the magnetic north made the south end of the needle dip and stick to the card.
I found later that when compasses are made, they are balanced for the zone that they are going to be sold, and that the manufacturers have indentified 5 zones of dip.
MAP OF THE FIVE ZONES
Compasses sold in North America are adjusted for the zone one, and where I was in Argentina was considered zone four. Compasses sold over there by the sporting good stores where adjusted for that zone.
If you have opportunity to travel to Australia, you will be in zone five and the dip of the needle will be even more pronounced.
ENTER THE GLOBAL NEEDLE
Suunto has come out with a couple of traveler’s compasses with a global needle. Brunton has at least one in their line and maybe other manufacturers are doing the same.
This is a needle that is optimized to be use in all places (that is why they are called Global compasses). Brunton is making the 8096 AR (a racing compass) with the global needle, and it makes sense as the runners don’t have to stop and level the compass perfectly to take readings as the global needle can work with even a 20 degree tilt.
Climbers can benefit from a global needle as they have more latitude to take a reading from a peak that is too close, as sometimes bearings have to be taken using the imaginary center line of a mountain instead of a peak when using the regular compasses, as the tilt upward will ground the regular needle. With the global needle the chances that you can still use the peak for your target are increased if the angle is less than 20 degrees.
So we should welcome the development of the Global needle and hope that more choices will be made available in the different models of compasses.
All the best
Black Bear
