Quite early on, computer simulations of the exact motion of a small number of stars was attempted (20 to 50). With the arrival of faster computers (IBM 7030, Atlas, IBM360/195), the possibility of simulating a galaxy of 2000 stars became possible and with it the need to display the results over time.
Roger Hockney's paper Gravitational Experiments with a Cylindrical Galaxy shows the results from a number of simple gravitational experiments via the Lockheed Stromberg-Carlson SC4020.
Frank Hohl's paper One- and Two-Dimensional Models to Study the Evolution of Stellar Systems suggests that spiral galaxies are young galaxies which later develop into elliptical galaxies
Hockney's paper Galactic Experiments with Differential Rotation shows some frames from the Lockheed SC4020 computer animation that he produced. After a period at IBM Yorktown Heights, he became a Professor at Reading University and used ACL's SC4020 for generating further computer animation.
In the BBC Tomorrow's World programme on Computer Animation, Hockney's galaxy evolution is shown near the end.
BBC Tomorrows World
By 1968, Frank Hohl had started performing calculations with 10,000 stars.
Sverre Aarseth of Cambridge University used both the Atlas and later the IBM 360/195 after ACL's merger with the Rutherford Laboratory. Initially for direct integration of star cluster models of 250 particles. He produced a film that explains his Computer Simulation of the Expanding Universe. It shows the 360/195 computer and the FR80 microfilm recorder (that replaced the SC4020). The film was produced by Paul Nelson with the help of Peter Hadingham's Swift Film Productions. See The N-Body Problem (1968) which has a copy of the film.
other papers by Frank Hohl and Roger Hockney are:
Computer Experiments on Low Density Crossed-field Electron Beams (Levy, Hockney 1967)
Computer Simulations of the Evolution of Spiral Galaxies (Hohl 1968)