Example of constructing an artificial cluster out of the “pure” Westerlund 2 population. The CMD is shown in the left panel. The green points mark the apparent position of the member stars as they are in Westerlund 2, the blue points indicate correction for reddening, and the red points reflect the additional reddening to the newly inserted artificial cluster. The distance modulus change was not applied here. The right panel shows the change in the apparent position of the member stars as they are “moved” from the distance of Westerlund 2 further out to the distance of the new artificial cluster. Black points on both panels are stars that were removed or merged because they came closer than the adopted limit to other stars that are brighter than them. For details, see Sect. 3.1.