Modern astrophysics operates with source parameters obtained
in different spectral wavelength ranges with the goal to obtain a global
understanding of physical properties and radiation processes
in these objects. An ability of using different
catalogs makes this problem considerably simpler. Lately
Different attempts have been made for combining many astronomical catalogs
in unified databases NED, SIMBAD, ESIS, ADS, etc.(see reviews by
Andernach et al.1994; Andernach 1995).
Important shortcomings of these databases are
(a) the incompleteness of the information stored compared to that offered in the original publication and
(b) the necessity to copy the whole catalog (if available at all) for dedicated work with it.
We propose a new solution to this problem with a ``CATalogs supporting System'' (CATS) at Special Astrophysical Observatory (SAO). It allows users to operate with astrophysical catalogs coded in plain ASCII, to cross--identify different radio catalogs, to calculate spectral indices, to construct and fit spectra, select data by various parametes: equatorial and Galactic coordinates at different epochs, flux densities, sizes, etc. This database is now running under the freely distributed UNIX version OS Linux (now Red Hat release 4.2 version) at the RATAN--600 server with a Pentium processor www.ratan.sao.ru and the SAO site cats.sao.ru (in the main laboratory building) of SAO of Russian Academy of Sciences (RAS), and constitutes the essential part of the data bank of SAO RAS (Kononov, 1995, 1996).