Relative to Neptune, the amplitude of libration is 38°, and so the angular separation of Pluto's perihelion to the orbit of Neptune is always greater than 52° (90°–38°).
Relatif terhadap Neptunus, amplitudo librasinya 38°, jadi pemisahan sudut perihelion Pluto dengan orbit Neptunus selalu lebih besar daripada 52° (90°–38°).