John Bresina, Will Edgington, Keith Swanson, Mark Drummond
In this paper, we present a fully operational system that performs closed-loop observation scheduling and execution and has been in daily use on an automatic photoelectric telescope at the Fairborn Observatory on Mt. Hopkins in Arizona. The scheduler is part of the Associate Principal Astronomer system that also provides tools that enable the effective management of au-tomatic telescopes. The paper describes the flex-ible schedule representation used and describes how the uncertainties and errors inherent in the domain are handled.