Comparison of the velocities in this catalog and the sample from Arnaboldi et al. (1998) for the 23 PNe in common. The previous measurement has been subtracted from the newer one on the vertical axis and the errors have been combined in quadrature. The median difference is 1.08 km s^-1. The scatter in the differences (70.7 km s^-1) is explained by the combined instrumental errors of the two samples. This indicates that the absolute velocity calibration of this sample is accurate.