Wavelength-dependent images of the central region of the Toby Jug Nebula around the AGB star HR3126. The images reconstructed in the continuum and six ¹²CO and ¹³CO first overtone band heads are shown. (a) Observed spectrum of HR3126. The images reconstructed at the wavelength channels marked with the filled dots are shown in the panels below. (b–o) Columns correspond to the wavelength channel in the continuum or in the CO bands as marked in panel a. The upper and lower rows show the images convolved with the beam size of 1.8 mas (shown in the lower left corner of each panel) and the unconvolved images, respectively. The images are flux-calibrated as described in Sect. 4.1.