During Campaign 3 of the K2 Mission we observed Neptune at 1-min cadence for about 65 days. We made a movie of the motion and it’s really amazing. Jason Rowe has the best, most polished version but I’m posting my version here because I have a slightly different contrast that means if you look very carefully you can see the irregular satellite of Neptune called Nereid. Nereid follows behind Neptune about a third of the movie width back.
Triton rotates around Neptune every 5.9-days in an orbit fairly close to face-on (120 degrees) and in a retrograde direction.
The science we are trying to do with these observations is to try to detect seismic oscillations from Neptune. Just like bells ring, so do planets. By measuring the frequency of that ringing we may be able to discover something about the composition of Neptune.
I also added a cheesy soundtrack.
Here is Nereid for those who couldn’t find it, circled in red.