Combined HR diagram for stars in Melotte 20 (α Per cluster; maroon squares), Melotte 22 (Pleiades; orange triangles) and IC 4665 (blue circles). Stars have been dereddened individually following the standard techniques of Johnson & Morgan (1953) and displaced by the distance modules calculated from TGAS. Spectral types in bold indicate standards in the main grid. Spectral types in italics are from the literature. The solid line is the observational ZAMS.