Dynamically scheduling observations of moving objects: the Catalina Sky Survey queue manager

The Catalina Sky Survey (CSS) at the University of Arizona has discovered 47% of all known near-Earth objects (NEOs) and contributed 59 million observations to the Minor Planet Center.([)(1],)([2]) CSS operates three telescopes fulltime, two of which primarily survey for new moving objects and one that follows up specific objects, particularly recent discoveries that may be NEOs. To be as efficient and effective as possible, CSS developed a flexible queue manager that enables all of our telescopes to perform both survey and follow-up observations as needed. The rate of discovery of new NEOs has increased greatly over the years, requiring a quantity of follow-ups that can only be accomplished with automated observing coordinated by a queue manager. Imaging moving targets also adds complexity, particularly the need for proper time intervals between images or the use of "track and stack" observing, necessitating that observations of multiple moving objects be properly interleaved in time. Targets are also added to and removed from the queue throughout the night when new discoveries are made or when objects are followed up by other telescopes. The CSS queue manager addresses all these challenges.