Initialiser for rotator class.

Arguments:

portname:       The device name of the serial port which the
                Taranis stepper motor controller is connected to.
telescope:      A rotator.telescope object containing observatory
                specific information.
target:         A rotator.target object contain details of the target
                field for observations.
idle:           The peak motor current when the motor is stationary,
                in amps.  Must be >=0 and <= run.
run:            The peak motor current when the motor is moving
                continously, in amps.  Must be >= idle and <= boost.
boost:          The peak motor current when the motor is accelerating/
                decelerating, in amps.  Must be >=run and <= 4.5.
dt:             The interval between tracking corrections, in seconds.
name:           label used for logging purposes.

Should be called by the parent instrument object's destructor to enable status information to be saved to file on exit.

Sets the motor currents to be used by the rotator.

Arguments:

idle:  The peak motor current when the motor is stationary, in amps.
       Must be >=0 and <= run.
run:   The peak motor current when the motor is moving continously,
       in amps.  Must be >= idle and <= boost.
boost: The peak motor current when the motor is accelerating/
       decelerating, in amps.  Must be >=run and <= 4.5.

Creates an instance of rotator.tracker thread and sets it running
for the currently set telescope and target.

Arguments:

logData:   Boolean to indicate whether tracking status information
           should be logged to the file 'dicstrack.log'. Default False.

 Moves the rotator by an angle in degrees(default is 1.0deg) 
 MoveTimeSec is to be the time step for the move. This could be
 sepecified as a rate RotRate in Degrees/sec.

 The Taranis software has a time step parameter which
 I have yet to understand. 

 See rotator.where for getting rotator location 


History
   20060605 Original by rgm