The Australia Telescope Compact Array (ATCA) , is located at the Paul Wild Observatory near Narrabri, some 550 km northwest of Sydney. Displayed are five of the six 22-m Cassegrain antennas , here arranged in one of the hybrid configurations which include two antennas on the North-South spur. The ATCA is a radio interferometer with maximum baselines of 6 km, working in the 1 – 100 GHz frequency range. Its supercomputer, the Compact Array Broadband Backend (CABB), is described in this paper by Wilson, Ferris, et al. 2011 (MNRAS 416, 832).