Residuals of effective temperatures (left panels) and surface gravities (right panels) determined with our empirical fit formulae to Q,  [u − b] ,  [c1]  and β and the spectroscopically derived reference values (Table 1). The dashed lines denote perfect agreement and the dotted lines correspond to the following 1σ-values: 700 K a), 943 K c), 1060 K e), 0.08 dex b), 0.19 dex d), and 0.08 f). See the text for details.