Lines fitted to the angle space (red dashed line) and the frequency space (blue line) of stream O7 evolved in a time-dependent (top) and static potential (bottom) using the same (correct) final potential. Additionally, the green line shows the track of the progenitor assuming the potential is static (i.e. θ_cm(t) = Ω_cm(t_f)t), and the grey line shows the line fitted to the frequency space at the beginning of the simulation. The inset labels show the numerical values of the aperture angle (misalignment) between the stream and the (static) progenitor orbit Ψ_{S, O}, and between the stream in angle and in frequency space Ψ_{Δθ, ΔΩ} (see Eqs. (34) and (35)).