Observed 250 μm surface brightness I_nu(250μm) (frame a), colour temperature T (frame b), and the 250 μm (frame c) and 500 μm (frame d) residuals in the RT model of the field G110.62-12.49. Colour temperature is estimated from observations using β = 1.8. The residuals are calculated as r = (I_Obs − I_Mod)∕I_Obs, where Obs and Mod refer to observed and modelled values, respectively. All maps are at 40′′ resolution.