Running median for the difference between EC photometric and Hipparcos parallaxes vs. Hipparcos parallax (left) and vs. T_eff photometric index indicator (right). Top: early region using CR78 ([c₁] indicating T_eff). Middle: intermediate region using GR78 (a indicating T_eff). Bottom: late region up to A9 using CR79 (Hβ indicating T_eff). The solid line shows the moving median and the dashed line is one standard deviation. Parallaxes are given in mas.