Variability of observed polarization for DH Cep plotted on the Stokes (q, u) plane, represented by the ellipses of the second harmonics of the Fourier fit. Blue, green, and red colors represent the B, V, and R passbands, respectively. The clockwise direction and phases of the orbital period are depicted for the B band ellipse. The angle between the major axis and the q-axis gives the orientation Ω. Average interstellar (Ref 21) Stokes q and u parameters are depicted as circles with ±σ error bars.