Galilean moons

these are precise positions of Jupiter's moons as seen from Earth.

every 6 hours, this twitter bot tweets an animation of the path of the moons over the next 6 hours.

one 6 hour period

tweet @ the bot

if you tweet a unix timestamp it will respond with a rendering of the positions of the moons at that exact time.

@jupiternow 499152060

the bot's reply

source code
ephemeris from Astronomical Algorithms