Example of measured spectra (left column) of CO(3-2) and HCN(4-3) lines (black) at the position of the sky western equatorial limb, at an offset from Neptune centre (−1.1″, 0.0″). Individual Gaussian fit components with FWHMs of about 4, 20, 80 km s⁻¹ are shown in dashed blue and their sum in red. Also shown: the beam-convolved solid body velocity (black dotted line) and the fit velocity (red dotted line). The difference of these two velocities allows us to derive the Doppler winds. Right: normalized wind contribution functions (WCF) at the limb for each molecule.