Of course, the Earth orbits the Sun also. On September 22nd of every year, the Earth is at about RA = 0, Dec = 0. Draw a small + (plus sign) mark at that point with permanent marker and label is “Sept. 22nd”.
Now, rotate the model so that the ecliptic (the circle of asteroids and planets, which includes Earth) appears perfectly horizontal. Imagine that you are standing on the Sun (at the center of the cylinder), looking out at the Earth. You can see light rays going from the Sun out to the Earth. At what angle do these light rays hit the cylinder? (Assume that an angle of zero degrees means the rays hit straight up and down.)