According to the resolution of the International Astronomical Union, since 1999 the main reference for spherical coordinates has become the international celestial reference frame ICRF, compiled from observations of quasars and point-like radio galaxies. This decision abolishes the observations necessary for compiling the traditional spherical coordinate system represented by the fundamental catalogs of the FK series. It is useful to recall the principles of astronomers of the 18th–20th centuries who had organized the determination of the absolute coordinates of stars at the state observatories, required for compiling the next fundamental catalog. This will allow natural scientists who study movements by measured coordinates of celestial objects, firstly astronomers and geodesists, to compare the opportunities provided by optical fundamental catalogs and the reference system of radio coordinates for solving the problems of their branch of science. Let us turn to historical experience, which shows that the establishment of main optical coordinate systems was not a volitional decision but was affirmed in the process of searching for the most effective method for solving both fundamental problems and satisfying current needs of each historical era.