Jet precession in Cep E. Top: wiggling model. The jet precession axis is represented by the continuous gray line. The jet moves over a cone of half-opening angle β It makes an inclination angle i with respect to the plane of the sky (α′,δ′). The locus of the ejection direction is drawn by the red curve. In the plane of the sky (α′,δ′), the projection of the locus is represented by the black line. Bottom: projected view of the jet axis associated with the current high-velocity emission, the previous ejection associated with knot NB, and the precession axis δ′, superimposed on the CO 2–1 outflow emission (see Fig. 1).