CCD spectrophotometry of CVs. III. 3270-9000A atlas for 38 faint systems.

A 7 A resolution, 3270-9000A spectrophotometric atlas is presented for 38 objects from the Downes & Shara (1993) catalogue of Cataclysmic Variables (CVs). The stars were selected among those listed as lacking published spectra. As for previous papers in this series, the aim is to check the CV status of the objects spectroscopically and to provide high quality absolute spectrophotometry over a wide wavelength range. For all programme stars accurate UBVRI magnitudes, continuum fluxes at selected wavelengths and integrated fluxes of emission lines are derived. Among the 38 programme stars, only 16 clearly show a CV-like spectrum. In the three papers of this series we have so far surveyed 94 objects among the entries in the Downes and Shara catalogue which lack spectroscopic confirmation. The fraction of validated CVs is 56%. For objects from the Palomar-Green survey the rate of confirmed CVs is particularly low, amounting to only 23%.