Strong lines in the red part of the solar spectrum. Disk-center profiles of the Na line (Na I 5895.940 Å; dotted), the Mg line (Mg I 5172.698 Å), the Ca line (Ca II 8542.144 Å) and Hα (H I 6562.808 Å, dotted) from the FTS atlas are shown on common scales. The atlas calibration by Neckel & Labs (1984) was used to convert the intensities into formal brightness temperatures. The wavelengths were converted into formal Dopplershifts from line center, with redshift positive.