How to camera match move for moon/clouds/stars?
You can assume celestial bodies are infinitely far away, as the amount of parallax you can achieve in anything except a space ship is infinitesimal. So that means that the moon and stars stay fixed to a point of view, as long as you're not panning. If you're panning then the moon and stars can be on layers a long way from the camera, but scaled up to fill the frame.