Journal: Proceedings of the Journées 2014 "Systèmes de Référence Spatio-Temporels" Z. Malkin and N. Capitaine (eds), Pulkovo observatory, 36-37
In earlier work (Kurdubov & Skurikhina, 2009) we had suggested ranking method of sources sets in order to select the list of sources that better define the orientation parameters of rigid rotation transformation from one system to another. The transformation parameters formal errors were selected as characteristic of sources set. For all catalogues IVS WG2 was selected special order in the sources list and obtained transformation parameters accuracy as function of the number of sources. For all catalogues that function has a minimum between 300 and 400 sources, adding the sources after the minimum leads to increasing formal errors of orientation parameters. After that we selected the common sources which placed before minimum of functions and obtained the “optimal set”.