Observed (black histogram, Escalante et al. 1989) and predicted H76α profile in the non-LTE (blue lines) and LTE case (red line). For the non-LTE case, we have plotted the predicted profiles for two different outflow terminal velocities, 60 and 80 km s^-1 (solid and dashed lines, respectively). We clearly see that the line width is only explained if one assumes 60 km s^-1.