Visible spectrum of VW139 (solid line) in the region of the CN and C₃ emission bands (in erg cm^-2 s^-1 Å^-1) compared to the spectrum of active comet 8P/Tutle (dashed line) obtained on Jan. 1, 2008 (Lara, pers. comm.). The spectrum of VW139 is averaged over an aperture of 40 pixels, i.e., 10.16 arcsec, meaning 12 300 km at the comet distance, and is multiplied by 50 for a better comparison with the spectrum of 8P/Tuttle.