Probability of seeing the companion at a single arbitrary time as a function of magnetic inclination angle α and spin-orbit misalignment δ. The orbital inclination angle i was fixed to 43.7°. Both α and δ are symmetrical about 90°; we therefore only show the [0°, 90°] × [0°, 90°] quadrant. For PSR J1906+0746, (α, δ) is (80.54°, 72.55°) from Wang et al. (in prep.). Its location is marked with a star. Upper panel: Probability of observing emission from at least one pole. Bottom panel: Probability of observing emission from the two poles. The assumptions here are (1) the beam extent in the latitudinal direction is 40° for MP and IP (equivalently, the impact parameter β is [−20°, 20°]); (2) we observe using an ideal telescope, and the probability is derived from a purely geometrical consideration.