Structure of a pulsar, illustration. Colour-coded parts of a pulsar. In white is the neutron star. Its powerful magnetic field is shown in blue. The north and south poles of that magnetic field, and the directions from which the pulsar's beams shoot, are in yellow. In red is the axis of rotation of the star. That axis is offset from the beam, which is why when the star spins, the beam sweeps past us creating pulses in the observed radiation.