Map of the relative positions of the H30α centroid emission in MWC 349 A for the velocity range between  − 49 km s^-1 and 53 km s^-1. The positions of the line channels are shown as crosses labeled by their LSR velocities with the blueshifted and redshifted velocities shown as dashed blue and solid red lines respectively. Maser spikes peak are shown as blue and red circles. Errors are shown by horizontal and vertical bars. The offsets are in milliarcseconds (mas) relative to the continuum centroid.