Channel map of the Λ-doubling lines within level v, N_J = 0, 16_33/2 observed towards R Dor. The colour map gives the line intensity in mJy beam⁻¹ and the contours show the continuum at levels of 20%, 40%, 60%, and 80% of the peak. We give the observed frequencies not corrected for the source systemic velocity. The full width at half maximum of the reconstructing beam is shown by the grey ellipse in the upper left panel.