Astronomical coordinates at the Parkes radio telescope.

The design and operation of the control system for the Parkes radio telescope are described. A coordinate transformation computer is utilized for transforming position requests into commands for the telescope drive; a diagram of the computer is provided. The coordinate transform techniques employed by the computer to transform position requests are discussed. The new control system allows for scanning the telescope in any astronomical coordinate system, the definition and use of beams offset in azimuth and elevation from the telescope's optical axis, and the definition of arbitrary coordinate frames which may move with respect to standard reference frames.