Same as Fig. 7 but in Schwarzschild spacetime for a vertical magnetic field. It might seem surprising that there is a small kick on the astrometric path toward the southeast. This is due to the dependence of the radiative transfer coefficients on sin θ_B, where θ_B is the angle between the direction of the magnetic field and the direction of emission (see Marszewski et al. 2021). The upper-left panel clearly shows a flux depletion toward the southeast due to this effect. At this orbital phase, the direction of emission in the emitter’s frame, K, becomes vertical and parallel to the magnetic field. Due to the combination of special-relativistic aberration and general-relativistic lensing effects, the direction of K varies with the orbital phase. The QU loops of this figure should be compared to that of Fig. 7, as the similarity is striking.