Left panel: 22 GHz VLBA contour map of the radio continuum emission from the nucleus of IRAS 15480. Contour levels are 4, 5, 6, 7 × 0.1 mJy/beam. The star indicates the position of the brightest maser spot (M1) at v = 9106 km s^-1, while the plus sign marks the position of the weaker maser feature (M2) with a velocity of 8994 km s^-1. The positions are plotted relative to the centre of the map (i.e. the position of the optical nucleus of IRAS 15480). Top right panel: VLBA spectrum of the brightest maser spot M1. The channel spacing is 0.2 km s^-1. Bottom right panel: VLBA spectrum of the blueshifted maser feature M2. The channel spacing is 1.8 km s^-1.