Phase connected TOAs from the Fermi-LAT (yellow cross markers), the ASTROSAT CZTI (green circles), the GMRT (purple plus markers) and the ORT (gray diamonds) observations. The phase connection was obtained with the high cadence TOAs derived from the ORT observations and then applied to TOAs from other telescopes. The systematic pattern in the timing residuals is due to timing noise. The TOAs for different telescopes are offset with each other due to relative delays in the data acquisition at each telescope.