  The Gravitational-wave Optical Transient Observer (GOTO) is a wide-field
telescope project aimed at detecting optical counterparts to gravitational wave
sources. The prototype instrument was inaugurated in July 2017 on La Palma in
the Canary Islands. We describe the GOTO Telescope Control System (G-TeCS), a
custom robotic control system written in Python which autonomously manages the
telescope hardware and nightly operations. The system comprises of multiple
independent control daemons, which are supervised by a master control program
known as the "pilot". Observations are decided by a "just-in-time" scheduler,
which instructs the pilot what to observe in real time and provides quick
follow-up of transient events.
