Ca II triplet and O Iλ8446 emission complex of the nuclear region for different circular extraction radii r_a from the MUSE cube. The spectra are normalized and shifted in flux for clarity. For increasing aperture radii (top to bottom), the influence of stellar Ca II triplet absorption becomes stronger. For extraction radii r_a larger than $0\stackrel{″}{.}50$, the host-galaxy contribution starts to dominate, effectively suppressing the nuclear double-peaked Ca II triplet and O Iλ8446 profiles. The spectrum with the optimal extraction radius r_a of $0\stackrel{″}{.}20$ is plotted in bold.