A graphical method for the selection of glasses which makes possible achromatic correction of a telescopic system of four cylindrical lenses which has a given Petzval sum and a given angular magnification in the first principal section, and which is to be corrected for the two aberrations of astigmatism and distortion, resulting from the anamorphotic effect, is described. The method is simple and much more effective than a previous calculation method. An illustrative example is given.