Fig. 12

S/N of individual spectra of calibrating cluster stars in open and globular clusters. There are typically >3 exposures per star per setup. The required S/N per star after combining at least three spectra per star was >50, thus individual exposures peak roughly around 30–40 for GIRAFFE, who was driving the total exposure time. A tail of low S/N spectra for UVES contains mostly archival spectra of subgiants and MS stars.
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