Accuracy analysis of equivalent width measurements in the spectra of slowly rotating A–F-stars

Based on the measurements made by the authors and published in the literature, the work analyzes the equivalent widths of spectral lines in the spectra of slowly rotating A–F-stars. The accuracy of the measurements made with $1.5$-meter RTT-150 telescope is in good agreement with the data obtained with modern coude' echelle spectrometers. The published data obtained using classical spectrometers contain substantial accidental and systemetic errors, which lead to inaccuracies in chemical abundance determinations.