NGSLstars and our sample in a log T_eff, log g diagram.NGSL stars (Koleva & Vazdekis 2012) are separated by abundance, [Fe/H] > −1 (red plus) or [Fe/H] ≤−1 (blue plus). Hot star library candidate stars are marked with circles. The circles are filled for stars that were observed and included in this paper. All O star candidates (blue) were observed, but not all PAGB stars (green) or He-burning stars (red). To guide the eye, an approximate Eddington stability line is drawn, and approximate spectral type boundaries.