Schematic map of the MW adapted from Vallée (2014) indicating the position of the Sun and the line of sight through the window. We adopted a distance to the Galactic centre of R_o = 8 kpc. According to this picture, the line of sight should pass through the Sagittarius arm and the end of the long bar, and the far side of the Norma and Scutum-Centaurus arms. Red circles mark corresponding distances for the main peaks using A_Ks = 0.484 × E(J − K_s). Using A_Ks = 0.725 × E(J − K_s) the distances are systematically shorter (black diamonds).