The flag of Australia is a defaced Blue Ensign: a blue field with the Union Flag in the canton (upper hoist quarter), and a large white seven-pointed star known as the Commonwealth Star in the lower hoist quarter. The fly contains a representation of the Southern Cross constellation, made up of five white stars – one small five-pointed star and four, larger, seven-pointed stars.
The Southern Cross is one of the most distinctive constellations visible in the Southern Hemisphere,] and has been used to represent Australia since the early days of British settlement Ivor Evans, one of the flag's designers, intended the Southern Cross to refer also to the four moral virtues ascribed to the four main stars by Dante: justice, prudence, temperance and fortitude. The number of points on the stars of the Southern Cross on today's Australian flag differs from the original competition-winning design, on which they ranged between five and nine points each, representing their relative brightness in the night sky. In order to simplify manufacture, the British Admiralty standardised the four larger outer stars at seven points each, leaving the smaller middle star with five points. This change was officially gazetted on 23 February 1903.
- The flagpole on Parliament House is 81 metres (266 ft) tall and the flag measures 12.8 by 6.4 metres (42 by 21 ft), about the size of half a tennis court.