# How do you determine placement of multiple lunar bodies in the night sky?

One of the worlds I’m building has three moons in 1:2:4 resonance, with the full moons syncing up once a cycle, meaning all three are full at different times but at the same time when the moon with the longest orbit completes a single orbit.

What I’ve been thinking about lately though is where they would appear in the sky based on their orbit and phase, especially after finding the following image:

Now, as far as I’m aware, the moon appears in roughly the same place to an observer because both the moon and earth are in constant motion. However, with multiple lunar bodies, I get the feeling this movement will have a more pronounced effect on observation.

Essentially what I’m trying to figure out is where these moons would appear in relation to one another in the night sky and how much, if at all, they would appear to shift to an observer.

• I'm going to try and simulate this later, so what is the length of the orbits? Both of the Planet and it's moons Jan 7 '18 at 15:19
• @bendl: Planet's orbit is 568 Earth days, and the lunar orbits are 33, 66, and 132 days. There may be some decimals I'm neglecting, but these are the important numbers at least. Jan 8 '18 at 4:12
• Are the moons on exactly the same orbital plane as each other? What are their sizes and distance from the planet, or, if you have this information, what is their angular size from the planet? Jan 8 '18 at 22:19