firstly; another great project Stephen, and an awesome pic the result . . . and some stimulation;
Dean, it might be because our moon orbits about 5 deg. from the ecliptic that our sun and sibling planets follow as per wikipedia
https://en.wikipedia.org/wiki/Orbit_of_the_Moon
which surprised me, my first guess was 'because luna orbited at earth's equator and earth's axial tilt/wobble re the sun'.
cheers, L