The Australian Flag came into being after the the federation of the Australian States into the Commonwealth of Australian on 1 January, 1901. The Commonwealth Blue Ensign was selected a a result of a public competition (over 30 000 designs were submitted); although selected in 1901 and gazetted in 1903, it was not given Royal assent and adopted as the definitive Australian flag until 1954 in the Flags Act 1953 (Act No. 1 of 1954)! It is based on the Blue Ensign of the United Kingdom, is twice as long as it is wide, and consists of a dark blue field that can be notionally divided into four quadrants. There is a different motif in each of the upper and lower hoist quadrants and the remaining two quadrants of the fly share another different constellation motif.
The present Australian flag can be considered to consist of three main elements:
- The Union Jack in the upper hoist quadrant or first quarter (also know as the Canton), denoting Australia's historical links with Great Britain. The Union Jack itself is composed of red and white intersecting and overlayed vertical and diagonal crosses on a blue background,
- The Southern Cross in the second quarter (also known as the top or head) and fourth quarter. Consists of five stars in a more or less kite-like pattern - Alpha Crucis (7-point), Beta Crucis (7-point), Gamma Crucis (7-point), Delta Crucis (7-point) and the smaller Epsilon Crucis (5-point). The outer diameter of each of the 4 major stars is 1/7 the width of the fly and the inner diamter is 4/9 outer diamete; the diameter of Epsilon Crucis is 1/12 the width of the fly and the inner diameter is 4/9 the outer diameter. The constellation of the Southern Cross is a significant navigational feature of the southern hemisphere, strongly places Australian geographically and has been associated with the continet since its earliest days,
- The Commonwealth Star or Star of Federation , central in the third quarter or lower hoist, has seven points to denote the six states and the combined territories of the Commonwealth. The seventh point was added in 1909. The outer diameter is 3/5 the width of the Union Jack (3/10 the width of the fly) and the inner diameter is 4/9 the outer diameter.