The way we envision the stars is by imagining they're attached to a giant invisible sphere surrounding the earth. It is a total fiction, really - just a construction we came up with to help us get our heads around the complexity of it all ... The ecliptic, put simply is the plane of the earth's orbit around the sun. But since we all live here on earth, we observe the sun to be moving along this plane instead. Why? Because what would be the point of looking at things from the perspective of the sun? That's no use to anyone ... Ergo, it's an imaginary circle, as it's only a part of our human construction of the cosmos.
Benjamin Wood, The Ecliptic
ecliptic, imaginary, sun