optical pulsarsPulsars that flash at visible wavelengths. The two best known are the Crab and the Vela pulsars. The Crab pulsar appears as a 16th magnitude star but is pulsing with a period of 0.033 seconds; the optical flashes of the Vela pulsar, about 26th magnitude, were discovered by looking for faint pulses with exactly the period (0.089 seconds) of its radio emission. Optical pulses have also been detected from X-ray binary systems.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006