GTC MEGARA tomography of the inner shell of HuBi 1 in the [N II] λ6584 emission line. The heliocentric velocity range labeled at the bottom right of each panel corresponds to the velocity ranges defined in Figure 3 according to the top right labels. The leftmost panel corresponds to the systemic velocity. The arrows indicate increasing velocity difference with respect to the systemic velocity. The “cross” marks the location of the center of the inner shell. In all channels, except the one at the systemic velocity, which is contaminated by the emission from the outer shell, the surface brightness of the most extended contour is 3 × 10⁻¹⁷ erg cm⁻² s⁻¹ arcsec⁻². The highest contour is set at 95% of the emission peak, and the step between contours is constant for each panel. The spatial resolution of these maps is ≃1.″0.