Accuracy of temperature estimates for externally heated models as a function radial position. The frames correspond to 0.2, 1.0, and 10 M_⊙ mass models, with the outer radii given in the figure. The dashed black line and the right axis indicate the dust temperatures calculated with 10⁹ photon packages. Compared to this reference solution, the blue, cyan, and red symbols show the results (temperature ratios) for smaller samples of 10⁵, 10⁶, and 10⁸ photon packages. These are plotted for every fifth cell, starting with the centre cell, and adding small shift along the x-axis for better readability. The error bars show the 1σ temperature dispersion based on 100 independent runs.