23 October 2008

Compass Work

Scroll down my blog to see how to take a compass bearing...

What is Magnetic Variation?
Magnetic Variation is the difference between the North on your map and the North your compass points to.

Why is it important?
Because the direction you need to walk to get to your next point and the direction your compass points are slightly different. The difference between the two can mean that you miss the point you're aiming for.

How much is Magnetic Variation?
It varies depending on where in the country, or the world, you are. At the moment in Kerry it's 5 degrees. It's constantly changing slowly.

Where can I find the amount of Magnetic Variation?
On the side of your Ordnance Survey map.

How do I apply Magnetic Variation?
After taking your compass bearing, you add the amount of magnetic variation onto your compass bearing. So in Kerry, at the moment, you add 5 degrees.

Following A Compass Bearing
1. Take your compass bearing.
2. Double check your compass bearing.
3. Add magnetic variation.

4. Check you have nothing magnetic in your chest pockets (phone, head torch, etc).

5. Hold the bottom of the compass base plate against your chest.

6. Shuffle around, with your feet side by side, until the red compass needle lies directly on top of the red compass arrow (red on red).

7. The top of the compass base plate has a 'direction of travel' arrow on it. This direction of travel arrow is pointing directly forwards at where you need to walk.

8. Choose a point in the distance (lump of grass, bog hole, rock) which is in a direct line with you and your direction of travel arrow.

9. Put your compass away and walk to this point. When you reach this point take out your compass and pick another point in the distance.