Having found E, the next step is to correct the orbit for the fact that the body is at one of the foci of the ellipse, not at the center of the ellipse. The true anomaly f is the true polar co...Having found E, the next step is to correct the orbit for the fact that the body is at one of the foci of the ellipse, not at the center of the ellipse. The true anomaly f is the true polar coordinate of the body, measured from the pericenter to the body, in the plane of the orbit. So next we move the origin of this coordinate system from the Sun to the Earth, giving the geocentric cartesian ecliptic coordinates \left(x_{e}, y_{e}, z_{e}\right) of the body:
