SKYDIP effects

Currently, T_amb (the outside temperature) is used instead of T_cab in Eq. 8. The effect of this assumption is intricate, because it is used also in the SKYDIP in which F_eff and Waterare both determined. If the atmospheric opacities are low, the sky brightness T_sky is a linear function of the number of airmass, and thus

$$T_{emi} = (1.-F_{eff})*T_{cab} + F_{eff} * C^{te} * Water * Air\_mass$$ (32)

In this case F_eff is underestimated, because T_amb is usually lower than T_cab. An increase in Water will compensate the lower value of the forward efficiency. If the opacities are sufficiently high, the linearity is no longer preserved, and the fit will be bad. However, for 20 K difference between T_amb and T_cab, the effect on F_eff is only 0.01 for F_eff around 0.90.