Calibrated colour–magnitude diagram for Sh2-152. The red segmented arrow shows A_V = 20 mag (A_Ks = 2.04) and the main sequence is located at the distance determined in this study (3.21 kpc). The continuous blue line in the upper part of the main sequence corresponds to the best fit made to project the CMD stars to the main sequence, following the reddening vector. The position of the spectroscopically observed stars is marked with blue numbers.