[en] A large discontinuity has been observed in the period of PSR 1641-45. The period of 0.455 s has decreased by about 87 ns corresponding to a fractional change Δ P/P approximately 1.9 x 10-7. There was a corresponding small increase in the period derivative with Δ (dP/dt)/(dP/dt) approximately 1.6 x 10-3. (author)