The project provided centrally-purchased (and thus discounted) hardware, professional system administrators, and the developers to write astronomical data-reduction applications for the UK astronomy community and beyond. At its peak size in the late 1980s and early 1990s, the project had a presence at around 30 sites, located at most of the UK universities with an astronomy department, plus facilities at the Joint Astronomy Centre, the home of UKIRT and the James Clerk Maxwell Telescope in Hawaii. The number of active developers fluctuated between five and more than a dozen.