Estimating Δν_ACF in GLOBAL for the G-type MS star KIC 12069424. Top-left panel: global multimodal fit with DIAMONDS, with a regular structure in frequency resembling the asymptotic pattern of p modes. Bottom-left panel: resulting ASEF, here in standard resolution for plotting purposes, containing 31 local maxima. Right panel: ACF² (computed at the frequency resolution of the PSD) of the high-resolution ASEF (solid black line), with the interpolated ACF² using a resolution higher than the PSD (about 100 bins in total, solid red line), and the final Gaussian fit to the interpolated ACF² (dot-dashed blue line). The red and blue curves have been offset by +0.1 and +0.2 in amplitude, respectively, for a clear visualization. The vertical dotted line is Δν from the ν_max–Δν relation, while the vertical dashed green line is the final Δν_ACF.