Standard and inside-out Doppler tomography based on the H_α emission (a) and the H_β emission (b). For each spectral line a pair of maps in the top panels show the standard tomogram (left side) and the inside-out tomogram (right side). In the bottom panel, three frames accompany maps of each line. They are comprised of the middle frame showing the observed trailed spectra with the reconstructed spectra for the standard and inside out cases to the left and right, respectively. See text for details.