Example spectrum of Feige 110 obtained with FORS1 on March 13, 2006 (grism G300I+OG590; airmass X = 1.03). The signal-to-noise ratio per pixel on the continuum is  ~200. The main molecular absorption bands are marked. Superimposed are two LBLRTM simulations with PWV = 2 mm (dotted curve), and PWV = 6 mm (solid curve). In both cases the O₂ column density is 3.3 × 10²⁴ cm^-2. Note that at the time this spectrum was obtained, FORS1 was equipped with a Tektronik detector much less affected by fringing.