Normalised separation between the eRASS1 X-ray position and the selected counterpart as a function of r-band (LS10), G-band (GDR3) and W1 (CW2020) magnitude, for sources with secure counterparts (p_any> =threshold6). The separation is normalised by the one-dimensional positional uncertainty of the eRASS1 source. The expected 1σ Rayleigh distribution for normalised separations (Rosen et al. 2016) is shown in green. Lines indicate the median values of the parameters.