vObserver Timing Diagram

The finite state machine moves from one state to another. There is one main observing PROGRAM, and one (or more?) main calibration PROGRAMs. Definitions of capitalised terms are:

  • PROGRAM: A set of tasks, executed in order.
  • WHEN: An if statement with a timeout.
  • EXCEPTION: When something doesn't go according to plans (usually a timeout), there has to be a backup plan. This could be e.g. try the next field and add to a nightly bad field count, or give up, close the dome and message someone.
  • ADDITIONAL_CALIBRATION_SCHEDULE: We should decide on a simple way to take extra calibrations in bad conditions. This is really a FunnelWeb thing - we want to be able to monitor instrumental drifts to increase RV precision.

Observing PROGRAM

This could be a master program, run in a loop with all other programs returning to this. Other architectures possible...
  • Check conditions.
  • WHEN conditions OK, ask scheduler for next object. [EXCEPTION: automatically execute additional Calibration PROGRAM according to ADDITIONAL_CALIBRATION_SCHEDULE]
  • WHEN next object obtained, check type of observation needed. If calibration is stale, execute Calibration PROGRAM first. With non-stale calibration, execute slew commands:
    1. Telescope -> slew
    2. Guider -> begin exposing
    3. Instrument -> configure (are there any moving parts? maybe not needed)
    4. Starbugs -> configure
  • WHEN slew complete and Starbugs configured, ask Guider if ready to guide.
  • WHEN Guider ready [EXCEPTION: Guider not ready, try spiral one time]:
    1. Guider -> Guide
    2. Instrument -> Expose
  • WHEN exposure complete, check if this observation needs Calibration PROGRAM at the end. Run this if needed.
  • WHEN (optional) calibration complete, send message to archiver task.
  • WHEN message acknowledged, return to start.

Calibration PROGRAM

  • Turn lamps on, put flaps/telescope in correct position.
  • WHEN everything in place, expose.
  • WHEN exposure complete, send message to archiver task.
  • WHEN message acknowledged, return to calling PROGRAM.