Observed and derived parameters for the clusters NGC 6791 (black), NGC 6819 (red) and NGC 6811 (blue). The top panels show Δν vs. ν_max (left) and the derived luminosity vs. T_eff (right). The uncertainties in the individual points in the H-R diagram are only the intrinsic uncertainties (50 K, see text), the possible offset due to systematic uncertainties in the effective temperatures (110 K) is indicated with the black horizontal bar in the top left corner. Isochrones for NGC 6791 and NGC 6819 are shown in cyan. The results for the field stars are shown in gray without uncertainties. The histograms of the asteroseismic mass (left) and radius (right) are shown in the bottom panels for the clusters NGC 6791 (black solid line), NGC 6819 (red dashed line), NGC 6811 (blue dotted-dashed line) and in gray hatched for the field stars.