Navigating with the Southern Cross

A handy skill to have or a fun skill to show-off

Although navigation is now mostly done using GPS systems, or at least a map and a compass, knowing how to use the Southern Cross is still a handy skill to have.  The Southern Cross can be used to find south and from there, you can find whatever particular bearing you require.  This means if you are lost you may be able to find your way home or at least be certain you are not walking in a circle.

The Southern Cross is a reliable way of navigating.  Provided it isn’t obscured by cloud or hills, the Southern cross is visible in New Zealand at any time of night and throughout the year.

Why you can use the Southern Cross to find south

Because of the earth’s rotation, stars appear to travel in a large arc across the sky. Some will disappear below the horizon, but others, like the Southern Cross, never ‘set’ below the horizon. If you use a time exposure camera you can see these stars trace a circle in the sky. At the centre of these circles is a point called the South Celestial Pole (point 6 in the image below)

The South Celestial Pole part of the sky is directly above the South Pole. This means that if you stood at the South Pole, the South Celestial Pole would be directly above you.

Find the South Celestial Pole

The numbers in this section refer to the numbers in the image to the right.

(1) The Southern Cross is made up of four bright stars that form a cross.

(2) There are two other stars off to the side called the Pointers.

(3) Draw an imaginary line through the longest part of the Southern Cross.

(4) Draw an imaginary line between the two Pointers.

(5) Draw an imaginary line that intersects line (4) in the middle at 90 degrees.

(6) Where lines 3 and 5 intersect is the South Celestial Pole.

Find south, and north and east and west

Stand and face the South Celestial Pole and;

South is directly in front of you

North is directly behind you

West is 90 degrees to you right

East is 90 degrees to you right