S/2021 N1

S/2021 N1 — moon orbiting Neptune, explore its interactive 3D model in Cosmoscope.

Explore S/2021 N1 in a live 3D Solar System. Follow its calculated motion and inspect real astronomical data, distances and orbital facts.

One of the faintest moons ever found from the ground: confirming it took long, stacked exposures on three of the world’s largest telescopes. It loops backwards around Neptune about 50 million km out, taking some 27 years per orbit — the widest, slowest orbit of any moon known.

Radius

~7 km

Orbit

50.7 million km from Neptune

Period

27.5 years — retrograde

Discovered

2021 — Sheppard, Tholen, Trujillo and Lykawka, Subaru telescope

Announced

February 2024

Family

Neso group, with Neso and Psamathe

Record

The widest, slowest orbit of any known moon

Size

About 14 km across, estimated from its brightness

Explore S/2021 N1 in 3D

Cosmoscope places S/2021 N1 in the Solar System using astronomical ephemeris or orbital elements, updated for the simulation time. Explore its calculated motion, distance and orbital facts in the interactive 3D view. Accuracy depends on the orbital model and its valid time range.