Left panel: Na i 568.2 nm line and Sc ii 568.4 nm lines in the spectra of stars NGC 5634-2 (black solid line) and NGC 5634-3 (red dash-dotted line). The MyGIsFOS fit to this specific feature is [Na/H] = −2.22 for NGC 5634-2, and −1.72 for NGC 5634-3. Right panel: Na i 568.8 nm line in the same stars. Abundances here are [Na/H] = −2.15 and −1.76. The remarkable difference in Na abundance between the two stars is quite evident.