HR diagrams of the H-burning post-AGB sequences computed by M15 for different masses and initial metallicities (Table B.2). Tracks are presented from the beginning of the post-AGB phase when the H-rich envelope drops below M_env = 0.01 M_⋆ to the moment in which the star has already entered its white dwarf cooling sequence at L_⋆ = L_⊙. At that point gravitational settling should have already started to turn post-AGB stars into DA-WDs, a process not included in the present computations. Red lines indicate computed isochrones for different ages since the zero point defined at log T_eff = 3.85.