Pan-and-tilt modules are accurate

The PTU-D300 is a family of modular computer-controlled pan-and-tilt units designed for fast, accurate positioning of heavy payloads. They provide torque sufficient for payloads up to 70 lb, while maintaining speed, precision, and a very small form factor. The units offer multiple mounting options and a single connection point and are designed for demanding applications that require high duty cycles and long life in harsh all-weather environments. Features include simple control from host computer via RS-232/485, 360° continuous-pan option with pass-through for many payload types, and a range of pan speeds (<0.0°/s to 50°/s).
Kane Computing
Northwich, UK
www.kanecomputing.co.uk