Sky distribution of galaxies in SCl A2142. The red symbols show galaxies with old stellar populations (D_n (4000) ≥ 1.55), and the blue symbols denote galaxies with young stellar populations (D_n(4000) < 1.55). The filled circles correspond to galaxies in rich groups with at least 10 member galaxies, the empty circles indicate galaxies in poor groups with 2−9 galaxies, and the crosses denote single galaxies. The grey circle has a radius of about 3 h⁻¹ Mpc and denotes the region of the cluster A2142 and its outskirts. The dashed line shows the supercluster axis.