In 1963, David Bellair (then 20 years' old) was a third year electronic engineering student at the University of Melbourne and a member of a student club, the Astronautical Society.
The Society was receiving radio signals from weather satellites. The Society needed a way of forecasting when the satellites would be over the horizon, so they would know when to turn on their radios. The calculations were initially done by hand, however this was tedious and error prone. So it was thought it would be better to try to do the calculations on the computer CSIRAC. David was keen to use the computer and Dr. Frank Hirst, head of the Computation Laboratory, was very encouraging and supportive.
Dr. Hirst thought they were solving 2nd order differential equations. The program was simple; it assumed that the orbits were very stable and the program added a constant number of seconds for each complete revolution and a constant change in longitude. The program only produced the orbits that were visible from Melbourne.
You could not see the satellites; they were too small, but you could see the separated third stage rocket casing.
When CSIRAC was replaced by an IBM 7044 transistorised computer, David rewrote the program in Fortran. Its capability was extended to include the azimuth and elevation of the satellite as the satellites passed overhead. This program was used for another year.
Working with Dr. Hirst and on the program made David realise computing was the career for him. After a short period as a physicist, he worked at Monash Computer centre as a senior lecturer before becoming a private consultant in information technology.