in Australia; and there is the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) in Canada and the US. Together, the consortia form the International Pulsar Timing Array (IPTA). The pulses from Millisecond Pulsars (MSPs) are used as a system of Galactic clocks. Disturbances in the clocks will be measurable at Earth. A disturbance from a passing gravitational wave will have a particular signature across the ensemble of pulsars, and will be thus detected. Significant pulsars The pulsars listed here were either the first discovered of its type, or represent an extreme of some type among the known pulsar population, such as having the shortest measured period. The first radio pulsar "CP 1919" (now known as PSR B1919+21), with a pulse period of 1.337 seconds and a pulse width of 0.04-second, was discovered in 1967. The first binary pulsar, PSR 1913+16, whose orbit is decaying at the exact rate predicted due to the emission of gravitational radiation by general relativity The brightest radio pulsar, the Vela Pulsar. The first millisecond pulsar, PSR B1937+21 The brightest millisecond pulsar, PSR J0437−4715 The first X-ray pulsar, Cen X-3 The first accreting millisecond X-ray pulsar, SAX J1808.4−3658 The first pulsar with planets, PSR B1257+12 The first pulsar observed to have been affected by asteroids: PSR J0738−4042 The first double pulsar binary system, PSR J0737−3039 The shortest period pulsar, PSR J1748−2446ad, with a period of ~0.0014 seconds or ~1.4 milliseconds (716 times a second). The longest period neutron star pulsar, PSR J0901-4046, with a period of 75.9 seconds. The longest period pulsar, at 118.2 seconds, as well as one of the only known two white dwarf pulsars, AR Scorpii. The first white dwarf pulsar AE Aquarii. The pulsar with the most stable period, PSR J0437−4715 The first millisecond pulsar with 2 stellar mass companions, PSR J0337+1715 PSR J1841−0500, stopped pulsing for 580 days. One of only two pulsars known to have stopped pulsing for more than a few minutes. PSR B1931+24, has a cycle. It pulses for about a week and stops pulsing for about a month. One of only two pulsars known to have stopped pulsing for more than a few minutes. Swift J0243.6+6124 most magnetic pulsar with G. PSR J0952-0607 heaviest pulsar with . PSR J1903+0327, a ~2.15 ms pulsar discovered to be in a highly eccentric binary star system with a Sun-like star. PSR J2007+2722, a 40.8-hertz 'recycled' isolated pulsar was the