Sketch of the orbits of PSR J0337+1715 (not to scale). Note that the orbits are nearly circular and that the ellipsoidal shape of the orbits on the left-hand sketch arises purely from projection. The osculating orbits of the system can be parametrised by the Keplerian orbital elements of the pulsar within the inner binary and of the inner binary within the outer binary (see text). In particular, a_p is the semi-major axis of the pulsar orbit within the inner binary, a_b is the semi-major axis of the inner binary within the outer binary and e_O its eccentricity. Are also shown the longitude of periastron the outer binary as well as the inner and outer inclinations with respect to the plane of the sky, i_I and i_O respectively. Note that for simplicity the sketch neglects the difference between the directions of the inner and outer lines of ascending nodes, δΩ, as it is in practice very small.