Z₂²-test for both nights joined. The orbital phase correction is shown with respect to the ephemeris value obtained from the timing solution by Jaodand et al. (2016). The maximum at 0.00129 corresponds to the shift of the epoch of passage at the ascending node by −22 seconds with respect to 54905.97140075 MJD. The aliases around the main peak emerge due to the presence of gaps in each data set and between them.