The southern cross is as Australian as meat pies. The Southern Cross is one of the most visible constellations in the Southern Hemisphere and right from the early days of the colony, it was being used to represent Australia. Perhaps the colonists identified with the Christian connotations, and the idea that god was somehow watching over Australia. Perhaps they identified with the four moral virtues of the Southern Cross, justice, prudence, temperance and fortitude, as defined by Dante. Perhaps they identified with the idea of a clear night sky, which was a distinguishing environmental characteristic when compared to Britain’s grey night skies.
For Navigation at night in the southern hemisphere it can be invaluable as it provides an easy reference to south for anyone who cares to look up into the sky.
Using the southern cross for navigation, or at least for finding south is overwhelmingly simple. Just look up and locate the southern cross.
Create an imaginary line joining the two stars at the ‘head’ and the ‘foot’ of the cross. Extend the line out another four lengths from the foot of the cross in a straight line. Then look straight down from that point to the horizon. You’ve found south!