Pulsar star. The neutron star retains most of its angular momentum, and since it has only a tiny fraction of its progenitor's radius (and therefore its moment of inertia is sharply reduced), it is formed with very high rotation speed. A beam of radiation is emitted along the magnetic axis of the pulsar, which spins along with the rotation of the neutron star. The magnetic axis of the pulsar determines the direction of the electromagnetic beam, with the magnetic axis not necessarily being the same as its rotational axis. This misalignment causes the beam to be seen once for every rotation
Spot beam Spot beam A spot beam, in telecommunications parlance, is a satellite signal that is specially concentrated in power (i.e. sent by a high-gain antenna) so that it will cover only a limited geographic area on Earth. Spot beams are used so that only earth stations in a particular intended reception area can properly receive the satellite signal. One notable example of the use of spot beams is on direct broadcast satellite systems such as DirecTV and Dish Network that deliver local broadcast television via satellite only to viewers in the part of North America from which those terrestrial broadcast stations