²⁸SiO ν= 0J = 5−4 spectra extracted from the line of sight towards the centre of Mira’s continuum from the full data images (line+continuum; red and magenta at the top) and from the continuum-subtracted images (blue and green at the bottom). The red and blue spectra correspond to the images from the actual data of Mira’s ALMA SV observation, and the magenta and green spectra correspond to the simulated data using CASA task simobserve. The imaging procedures for the observed and simulated data are identical.