It would be very helpful for navigation if it was easier to distinguish between the front and back of the orbits, to gauge the actual orientation of the orbital plane. To that effect, the back of the orbit (the half farther away from the player) could be rendered darker than the front. Obviously, in-game, the ship computer knows the full 3d orientation of known orbits, as they're available in the orrery view of the system map, so it could easily add that extra information.