Height of the scattering surface above the disk midplane as calculated from the centre offset of the visible rings and gaps of the disk (red data points). We added the height of the PAH emission surface calculated by Lagage et al. (2006) as a dashed green line and our own best fit to the scattering surface height as solid red line. The best fit to the scattered light data ignores the last two (with the largest separation) data points, which deviate from a power law profile presumably owing to a changing optical thickness of the disk.