SET ANGLE_UNIT

        [DISPLAY\]SET ANGLE_UNIT [Degree|Minute|Second|Radian|ABSOLUTE|RELATIVE]

    List  or Specify the angular unit and mode used for box labelling.  The mode
    can be ABSOLUTE to use sexagesimal notation in Hour - Degree for  Right  As-
    cension  and  Declination,  or RELATIVE to label with offsets in the current
    angle unit.

    SET ANGLE_UNIT
    will list the current and fallback units (if any)

    SET ANGLE_UNIT ABSOLUTE|RELATIVE
    will toggle between ABSOLUTE labels and relative ones in the current angular
    unit. ABSOLUTE labeling is not possible if there is a rotation angle in  the
    images: only relative labels are used in this case, whatever the mode speci-
    fied by SET ANGLE_UNIT.

    SET ANGLE_UNIT Degree|Minute|Second|Radian
    will  set  the current angle unit to the specified value, and enforce use of
    offset labels in the specified unit.