How would you add a moon to the background of a scene? (like the sun over Unity's horizon)

Unity lets the sun rotate along the X, Y, and Z axis outside of the scene boundaries; emulating a horizon along with the new Scene Volume system. I'd like to add an object (the moon) to this external scene space and have it go beneath the horizon when it comes into rotation.

Here's a visual of what I have implemented. There's an empty parent in-between the sun and the moon that can be rotated to emulate the night and day cycle. The moon (a sphere with an emissive material) has a directional light attached that sort of emulates the moon's reflection of starlight.