SPIPS code applied on the type-II Cepheid κ Pav. Above: radial velocities from Wallerstein et al. (1992) (the typical error bar is shown in the bottom left corner) and new measurement from CORALIE and HARPS (the size of the points corresponds to the errorbar), fitted using spline functions. Below: uniform disk angular diameters deduced from our PIONIER interferometric observations. For each panel we indicate the reference and the individual reduced χ².