july 2007
navigation without a compass
If you don't have a compass, or manage to loose it on route, you can still find north quite accurately using the sun (by day), or the stars (by night), as long as there is not too much cloud about.
Celestial/ Star Navigation
In the northern hemisphere you will need to find only one star. The hardest thing for some people is to forget myths they have learned over the years about certain stars and constellations.
The North Star is important because it never moves. It is always in the same place --the north sky. It is the very end of the handle of the little dipper. Measure the distance between the two stars that form the end of the 'pan' Now draw a straight line through those two stars. Measure along that line 5 times the thickness of the pan. That is where the North or Pole star is located. To check your work, if you are close to 30 degrees latitude, the north star should be three hand widths above the horizon. The farther north you go, the higher it will be in the sky. On the north pole, it would be almost over head. Near the equator it is invisible, and it's location must be approximated by looking for the big dipper or Cassiopeia.
In the southern hemisphere, you can find due south by looking for the southern cross. It rotates around the south pole. If you draw a line from the top of the cross straight through the bottom and on across the sky, the line will pass through a due south point. Remember this: If you are at 30 degrees latitude, the imaginary 'South Star' will about 3 hand widths above the horizon. There is no southern pole star.
But be careful. The False Cross is nearby... don't use it!!!!
Sun Navigation
Take a stick and push it into the ground straight up. Place a small rock on the tip of the shadow that is cast. Wait about 20 minutes and place another small rock on the tip of the 'new' shadow. Now draw a straight line between the two rocks. This line points east -west. Stand with your left toe on the first rock and your right toe on the second. Think of it this way -- if the sun moves from east to west, then the shadow moves from west to east, right? Based on the same principle, you can use sticks to determine direction from shadows.
1. Find a flat piece of ground and then put a stick upright in it. Mark the top of the shadow with a pebble or something else. A line drawn between these 2 points gives the west-east line with the first point being west. This is only really accurate around midday.
2.If you have more time, plot points for a whole day. The point on the curve which is nearest the stick is due north. See below:
If you have an analogue wrist watch, the kind with hands, showing the correct time, you can use the hands to find north. Hold your watch up in front of you, and let the short hand, that indicates hours point at the sun. While holding it like this, cut the angle between the red arrow and 12 o'clock in two, that way is south. Don't forget, this is based on GMT! If you are in British Summer Time, use the 1 instead of the 12, (as in the diagram right).
Many people wear digital watches these days. If you do, draw an analogue watch face on a piece of paper, and then mark the hour hand on using the digital watch. The rest of the method is identical.
Natural Signs
Normally, there will be fewer and thinner branches to the north. This is usually easiest to see if you look up along the trunk of the tree.
The north face of the tree would be more humid than the south face, which is something most species of lichen likes, and consequently, there will be more of it on the north face.
Ants also like to build their nests on the south side of the tree.
Making you own compass
You can make your own compass by magnetising a needle. Rub the needle about 24 times with a silk scarf or magnet. Suspend the needle in the mid-point on some string and it will point north.
from survival skills for scouts
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January 20, 2011, 07:58