Optical Timing of the Crab Pulsar, NP 0532

Absolute times of arrival of NP 0532 pulses have been measured over a 2-year period. The data are shown to be consistent with a cubic polynomial which describes the secular slowdown, a sudden increase and subsequent exponential decay of the frequency (the glitch of 1969 September 29), and an intrinsic 17j noise component in the frequency.