Final altitude profile obtained with HARPS, method 1, and with a Noxon correction for the Ring effect, expect in the deep telluric lines (Sioris & Evans 2000). A 10 Å bin is superimposed in light-blue over the full-resolution profile; 30 and 100 Å bins are shown too, shifted upwards for clarity. The Na I peaks are visible near 5900 Å. Oxygen and water-vapour absorption spectra at arbitrary scale are shown. The altitude profile has been shifted to have an altitude of 23.8 km in the [4520–4540] Å domain, as predicted by Ehrenreich et al. (2006) (dots and dashes in green – dashes to improve the visibility of the curve around 6000 Å).