[1][3] His studies of the Antikythera mechanism, in collaboration with Michael T. Wright, led to the first working model of this ancient analogue computer.

Bromley was born on 1 February 1947 and named after his uncle Allan, who was killed in New Guinea during World War II, and his father George, who died on 8 August 1962.

[citation needed] Bromley grew up on a 30-acre (12 ha) property at Freeman's Reach, on the Hawkesbury River, in New South Wales, Australia, in an historic home, "Sunny Corner".

He completed his secondary education at Richmond High School and in 1964, at the age of 17, his academic ability earned him a scholarship to study science at the University of Sydney.

[citation needed] Bromley graduated in 1967, with first-class honours in physics, and stayed on for a research degree in astrophysics He was awarded his PhD in 1971.

[citation needed] Bromley had an amateur interest in the history of mechanical inventions, and was aware of the ancestral figure of Charles Babbage.

Bromley's background in astrophysics paid dividends, and after several trips to Athens where he obtained radiographs of the inner mechanisms, and with the help of a clockmaker Frank Percival, back in Sydney, they produced a working reconstruction.

The pride of place was taken by four mechanical anti-aircraft gun predictors developed and built by the British government after World War I.

2 under the direction of Doron Swade: During several visits to London beginning in 1979, Allan G. Bromley of the University of Sydney in Australia examined Babbage's drawings and notebooks in the Science Museum Library and became convinced that Difference Engine No.

Working with Percival, he improved the device by altering the function of the handle so that one complete rotation would correspond to a single day, which he considered to be the most obvious astronomical unit.

Bromley worked with the same set of parts as Price, but suspected that a gap in the mechanism was originally home to several extra gears.