A number of pulsars are monitored at 18 cm and 13 cm wavelength, particularly for detecting glitches - sudden changes in the spin rate. Because they are so small, most pulsars cannot be seen with optical telescopes, even very large ones. Fortunately, they have extremely strong magnetic fields. The magnetic axis is offset from the rotation axis, so as the pulsar spins we see radio flashes when we observe it with a radio telescope. Ambulance lights make red flashes in the same way.
Pulsars originate when an old, massive star explodes as a supernova.
In this process, the core of the star implodes. The core collapses through the white dwarf stage until its constituent protons and electrons combine to form neutrons. If it is not too massive it can stabilise at this point as a very hot, incredibly dense ball of neutrons with a thin crust of ordinary matter on its surface. Real-time glitch detection software has enabled us to capture the behaviour of the pulsar from almost immediately after several of its glitches. This is what we observe from the Vela pulsar with the radio telescope at Hartebeesthoek.