Parameters

  Keyword    Type      Description
  -------    ----      -----------
 only apply to both axes
   RADEC      LOG       Display RA/DEC axes
   SCALE      LOG       Scale both axes equally
   WIDTH      INT       Linewidth for axes
   FONT       INT       Font for numeric labes
   SIZE       REAL      Character size of numbers
   BOLD       INT       Character boldness
   COLOUR     INT       Colour index
 setable for individual axes
   OPT       CHAR      Axis options code
   LO        REAL      Left limit of axis
   HI        REAL      Right limit of axis
   TICK      REAL      Spacing of major ticks
   DIV       INT       Number of minor divisions between major ticks
   LOG       LOG       Logarithmic axis