Quiet solar limb imaged in the continuum close to O i 7772 Å line and in its line core. Left panel: continuum image (810 mÅ from the line core). Centre panel: line core image. Right panel: line core image with intensity scaling to better show the off-limb emission. These images have not undergone any radial enhancement as in Fig. 2. The red arrow indicates a point on the limb where the dark gap is strong and where the radial intensity profile used to compare with modelling is extracted.