Automatic Observing Mode
By pressing the AUTO button, the LOAD command can be issued by commands from the observer's terminal, rather than repeatedly hitting the LOAD button in the console rack.
The automatic mode is activated or resumed after an observation has been started manually by hitting LOAD. A light in the AUTO button on the control desk indicates that the automatic mode is engaged and the observing program can be started from OBST .
To set the AUTO button:
a) Start an observation with an appropriate VERB (like POINTING).
b) After OBST answers with ``waiting for end of previous scan'' and ``Try the load button'', press the LOAD button.
c) Then press the AUTO button.
The OBSERVE Process
A high priority task, called OBSERVE, inspects the state and progress of the drive program. Whenever new procedures begin, it sends command lines to the off-line data reduction packages in much the same way as the user does for later reduction. In this process the raw data are converted into the preferred data structures of the reduction programs which is convenient for further data analysis. For calibration observations, CHEF automatically returns the calibration results which can be used for pointing and focusing through OBST commands. OBSERVE displays the progress of the current observation on one of the screen sections available to OBST . OBST interprets the actual observing states whenever it is requested to start a new observation.
The OBST WAIT state
The astronomical drive program can only execute one observation at a time. It internally uses a single passive option field. OBST has to coordinate the user commands with the drive program. Especially in the case of executing sequences of observing commands through SIC command files the observations have to be serialized. The coordination occurs in a synchronization state, called WAIT. The verb WAIT is only used inside the command procedures that start the observations, but should not be used in routine observations.