Finding North and South

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A great skill to have is to be able to find North and South at any time of the day or night, without needing a compass or cellphone.

Day navigation

Method 1: Watch hands

For this, you'll need an analogue watch.

  1. Rotate the watch until the sun is in line with 12:00 on the watch. If you are in Cape Town, meridian can be between 12:30 and 13:00, so you it will be more accurate to aim the sub between 12:00 and 13:00.
  2. Draw an imaginary line from the centre of the watch halfway between the hour hand and the sun. This line will point North.


Illustration of a method to identify north and south directions using the sun and a 12-hour analogue clock or watch set to the local time, 10:10 a.m. in this example, for both northern and southern hemispheres, with and without daylight saving.



Method 2: Shadow stick

Stick and shadow.jpg

To find north, you will need:

  • a straight stick about a meter in length,
  • 2 stones as markers,
  • a level piece of ground where the stick can cast a distinctive shadow.

Method:

  1. Place the stick in the ground so it stands erect.
  2. Make note of the shadow that the stick casts. Mark the location of the shadow's tip with one of your stones. (This stone will represent West.)
  3. Wait at least 20 minutes, but preferably an hour.
  4. Come back and mark the shadow's tip again with the second stone (which will represent East).
  5. Draw an approximate East-West line between the two stones.
  6. Bisect the East-West line to get North.



Method 3: Sunrise and sunset

The sun rises in the East and sets in the West. If it is close to sunrise, you will be facing East by facing the sun. If it is close to sunset, you'll be facing West.


This is actually why method 1 and method 2 above work. We are drawing an imaginary line across the sky from East to West, and using the time to determine where on the line we are currently.

Method 4: Moss on trees

In the Southern Hemisphere, the sun moves across the sky to the north (since we are south of the equator). This means that shadows are generally facing south. The south side is generally cooler, which is favoured by moss on trees. If one side of a tree has more moss on, it is likely to be the south side of the tree. This is also a reason why people prefer north facing houses - so they have more light.


Method 5: Prevailing winds

If you know the direction of the prevailing winds in an area, you'll be able to estimate direction from the natural angle of trees. In areas where there are strong winds, such as the South Easter in Cape Town, many trees tilt by being pushed by the wind. In Cape Town, the trees often tilt away from the South Easter, and point North West.


Night navigation

Southern Cross

Method 1: Length of the axis

Take the length of the long axis of the Southern Cross, and repeat this length 4.5 times. At the end of this imaginary line, drop vertically to the horizon which would be an estimate of South.

SouthernCross1.gif


Method 2: Using the pointers

Extend the axis of the cross like the tail of a kite, then intersect with a line bisecting the pointers. The point where the lines intersect is very close to the south celestial pole where the earth's axis points into the southern sky. This pole is visible anywhere in the southern hemisphere and lies directly south.

'Southern Cross - Orientation and navigation' [1]


See also

  1. Maggy Wassilieff, 'Southern Cross - Orientation and navigation', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/en/diagram/7486/navigating-by-the-southern-cross (accessed 2 December 2018)