Spectroscopic redshift histogram for galaxies within 30 arcmin of the ZwCl 1665 cluster position. The caption information is the same as for Fig. 7, with the addition that the orange histogram shows the number of galaxies with available SDSS DR14 redshifts. The Gaussian fit of the low-redshift peak gives 0.030 ± 0.002, while for the high-redshift one we obtain 0.097 ± 0.003. The likelihood distributions of the redshift parameter of the northeastern component is in purple, while the southwestern object is shown in blue.