Notes. Provided rotational elements are the rightascension, α_p, and declination, δ_p, of the pole orientation of Neptune referred to the ICRS. They are represented by trigonometric series in accordance with the IAU standard (e.g., Archinal et al. 2018). Listed parameters are the angles at epoch, α_o and δ_o, their rates, and , and the amplitudes, A_i and B_i, phases, N_i, and frequencies, Ṅ_i, for the series periodic terms. With these parameters, the series are written as and , where t is the time since the epoch 2000 January 1.5 TDB. We estimate the parameters by fitting these series to our integrated pole orientation motion from 1600 to 2650. Overall angular distance residuals are well constrained within about 0.′′ 08.