CCFs of H₂O for the six nights of WASP-69 b, using the optimised number of SYSREM iterations (3, 2, 6, 3, 2, and 2 iterations for nights 1 through 6, respectively). The planetary rest frame follows a trail between the dashed lines. The horizontal dashed lines indicate the contact points (T1, T2, T3, and T4, from bottom to top). Strong telluric residuals located at v = 0 km s⁻¹ are visible for some of the nights.