<title>Object oriented design of the Liverpool Telescope Robotic Control System</title>

Abstract

In the traditional, manned observatory, an astronomer must continually be weighing together many factors during the course of an observing run in order to make an appropriate decision on the course of action at that time. Weather conditions may force suspension of the observing program to protect the telescope, later to be resumed when conditions improve. Power outages may force controlled shutdown of computers and other hardware. Changes in sky condition may require on-the-fly changes to the scheduled program. For the Liverpool Telescope (LT), the Robotic Control System (RCS) is designed to act as a replacement for the duty astronomer. The system is required to be robust, reliable and adaptable e.g. to future instrument configurations and varying operational objectives. Consequently, object-oriented techniques which promote modularity and code re-use have been employed throughout the design of this system to facilitate maintainance and future upgrading. This paper describes the task management architecture (TMA) - a configurable, pattern based object model defining the cognitive functionality of the RCS, the environment monitoring architecture (EMA) - a configurable, rule-based decision making paradigm and the use of our proprietary Java message system (JMS) communications architecture to control the telescope and associated instrumentation.