Continuum intensity maps from 14 November 2010 (panel a)) and 16 November 2010 (panel b)). The contours are used to calculate azimuthal averages. The areas above the red lines were neglected because of the complex structure of the sunspot there. Azimuthally averaged parameters: Panel c) shows the radial dependence of B of the sunspot observed on 14 November 2010 (violet curve) and 16 November 2010 (red curve) with VTT/TIP-2. Panel d) represents the vertical gradient of the magnetic field strength (ΔB/ Δlog τ)_0.0,−2.3 as a function of r/R_spot. Shaded areas represent standard deviations. Dotted vertical lines in panels c) and d) indicate the averaged location of the umbra-penumbra boundary and the outer boundary of the sunspot.