code: private long lstToUT(double lst) {
          // Convert to local mean time
          double lt = normalize((lst - getSiderealOffset()) * 0.9972695663, 24);
  
          // Then find local midnight on this day
          long base = DAY_MS * ((time + fGmtOffset)/DAY_MS) - fGmtOffset;
  
          //out("    lt  =" + lt + " hours");
          //out("    base=" + new Date(base));
  
          return base + (long)(lt * HOUR_MS);
      }
docs: Converts local sidereal time to Universal Time.
  
  @param lst   The Local Sidereal Time, in hours since sidereal midnight
  on this object's current date.
  
  @return      The corresponding Universal Time, in milliseconds since
  1 Jan 1970, GMT.