Comparison of observed net surface brightness (dashed lines) and models with J13, AMMI, and THEMIS cases. The frames correspond to different model assumptions: the default parameters (frame a), cloud model with larger LOS extent (W = 1.7, frame b), four times larger intensity of the local radiation field (frame c), and the default model assuming no LOS sky background (I_bg = 0, frame d). Estimates Fig. 8 and include estimates for the areas marked in Fig. 8. The solid lines correspond to the larger area and the partly transparent lines to the smaller area. THEMIS results are shown only for the default case.