Comparison between the masses obtained by different combinations of the observational constraints available. Masses are determined using asteroseismic constraints (ν_max,Δν) and T_eff (black dots); using ν_max, T_eff, the extinction from Drimmel’s model, and the stellar radius from the Hipparcos parallax (using T_eff, red triangles); and using Δν and the stellar radius from the Hipparcos parallax (using T_eff) and stellar extinction by Drimmel’s model (green squares). Asterisks indicate stars that are members of NGC 6633.