Astrophile: Stopped clocks deepen pulsar enigmas: In the 1970s, some regular pulsars were spotted switching off for a few seconds to a few minutes, a phenomenon known as "nulling". And in the past decade, a new class of pulsars has been found , in which the silences can range from minutes to a few hours. They were dubbed rotating radio transients, or RRATs. Around the same time, a pulsar was found that pulsed for about a week and then switched off for about a month before repeating the cycle.
With an "off" period of 580 days, Camilo's pulsar has taken by far the longest break seen so far. Having switched back on only in August this year, it is too early to tell whether the year on/year-and-a-half off cycle is a regular thing, but Camilo says it makes him wonder what other pulsars are hiding.