English: Sped-up simulation of Neso's orbit around Neptune, from 1600 to 2400 (800-year duration). The orbit is being viewed directly above (north of) the ecliptic plane. The bright red fading trail with the white head represents Neso's position and trajectory over one orbital period at the given frame. The entire path of Neso from 1600 to 2400 is also shown in the background as a very faint, dark red tangled loop. For scale, the orbits of Neptune's two largest irregular moons Triton (tiny magenta dot) and Nereid (magenta outer ellipse) are shown; their orbits precess much more slowly compared to Neso.

While Neso's orbit nodally precesses around in a circle, it also warps and changes shape (inclination and eccentricity) due to the Kozai resonance. The Kozai resonance locks Neso's argument of pericenter to 90 degrees, so Neso's periapsis (closest approach to Neptune) is always positioned above the ecliptic (positive Z direction).

The trajectory of Neso is sourced from JPL Horizons, queried via Python's astroquery module. The 3D positions are visualized via Python's matplotlib module. The Python code for this was partially generated via Claude AI, but I have made necessary corrections (e.g. check queries, adjust timestep, speed, etc.) and visual improvements (labels, colors, opacities, etc.) to ensure that the visualization is accurate.