Spectra of the hydrogen recombination lines observed towards the peak of the UC HII region. The name of the line is indicated in the top right corner of each panel. The velocity is relative to the peak velocity of each spectrum, obtained with a Gaussian fit. The red and green curves are the model spectra obtained by fitting only the H39α, H40α, and H41α lines. The H54γ line is contaminated by emission from a molecular line.