code: def right_ascension(self):
          '''of ascending node'''
          nx,ny = self.node_line_vector
          n = self.node_line
          Ω = arccos(nx/n)
          if ny < 0:
              Ω = 2*π - Ω
          return f right_ascension(self):
          '''of ascending node'''
          nx,ny = self.node_line_vector
          n = self.node_line
          Ω = arccos(nx/n)
          if ny < 0:
              Ω = 2*π - Ω
          return Ω
docs: of ascending node