Spatial distribution of the H₂O masers in OH 231.8+4.2 at all epochs (top left: 1; top right: 2; bottom left: 3; bottom right: 4). The LSR velocities of the maser spots are indicated by the color bar to the right. The reference spot at V_LSR = 25.52 km s⁻¹ is located at (0,0). The blue and green stars in the bottom right map show the location of the SiO maser spots at 27.26 and 32.23 km s⁻¹, respectively.