Surface temperatures versus local time. Top: temperatures, T_H, for each pointing of observations listed in Table 2, inferred with the model M_H for daytime ones or with M_o for the ones left over (Table 4). The blackbody temperatures, T_B, estimated for the same spectra are plotted in black (+). Error bars on these estimates are about 1 or 2 K for dawn and dusk observations, and they decrease to 0.3 K at noon. Bottom: deviation ΔT = T_H − T_B for each pointing and their error bars. Local time is 0° at midnight and 180° at noon.