Global properties of NGC 6569 targets. Top left panel: spatial position. The color-coded symbols represent the S/N of stars (as labeled in the top right panel) with APOGEE spectra, whose sizes are proportional to their K_s magnitudes. Field stars are shown as gray dots. A circle with the tidal radius of 7.15′ (Harris 2010) is overplotted. Top right panel: proper motion density distribution of stars located within the tidal radius from the cluster center, color- and size-coded as in the top left panel. The inset in the top right panel shows a zoom-in of the cluster, squared in 0.7 × 0.7 mas yr⁻¹ and enclosed in a proper motion radius of 0.5 mas yr⁻¹, shown as a gray circle. The dashed blue lines are centered on the nominal proper motion values from Baumgardt & Vasiliev (2021). Bottom left panel: radial velocity vs. metallicity of our members compared to field stars. The [Fe/H] values for our targets have been determined with BACCHUS (see Section 5) using photometric atmospheric parameters (see Table 2), while the [Fe/H] values for field stars are from the ASPCAP pipeline (gray dots). The red box encloses the cluster members within 0.11 dex and 9 km s⁻¹ from the nominal mean [Fe/H] = −0.91 dex and RV = −49.75 km s⁻¹ of NGC 6569, as determined in this work. Bottom right panel: Color-magnitude diagram corrected for differential reddening and extinction in the Gaia BP band and 2MASS K band of our sample and stars within 7.15′. The best PARSEC isochrone fit of 12 Gyr is shown as a solid black line for NGC 6569 stars (gray dots) located within 7.15′ from the cluster center.