 leading and trailing
               blanks in `obsrvr' are not significant. Optionally, you
               may supply a string containing the integer ID code for
               the object.  For example both &quot;EARTH&quot; and &quot;399&quot; are
               legitimate strings that indicate the earth is the
               observer.
 
   spoint      is a surface point on the target body, expressed in
               rectangular body-fixed (body equator and prime meridian)
               coordinates.  `s