Data of V889 Her and maximum a posteriori model for T_s = 15 days and for grids with n = 6 (top row) and n = 8 (bottom row). The model has k = 2 and uniform latitude distribution for spots. The first plot on the left hand side represents data, second one represents the corresponding statistical model, third plot shows a high-precision model in a 100 × 100 grid, and the last plot visualises the corresponding differential rotation curve with 1, 2, and 3-σ uncertainties (dark to light blue). The high-resolution version of the model is added to enable visual inspection of the underlying distribution. The shades of red represent the distribution with respect to its maximum.