code: def isDiurnal(self):
          
          sun = self.getObject(const.SUN)
          mc = self.getAngle(const.MC)
          
          # Get ecliptical positions and check if the
          # sun is above the horizon.
          lat = self.pos.lat
          sunRA, sunDecl = utils.eqCoords(sun.lon, sun.lat)
          mcRA, mcDecl = utils.eqCoords(mc.lon, 0)
          return utils.isAboveHorizon(sunRA, sunDecl, mcRA, lat)
docs: Returns true if this chart is diurnal.