The determination of the zero point of the wavelength scale on stellar spectrograms A novel method for determining the zero point of the wavelength scale(lambda0) on low-spectral-resolution spectrograms obtainedwith an objective plasma is presented. The method was applied to a groupof 100 stars belonging to the B-G spectral classes. Near-UV spectrogramsof these stars were obtained by the Orion-2 space observatory.Equivalent widths were obtained for the resonance doublet of Mg II 2800A in the spectra of the stars studied.
