Far-IR SED of NGC 6781 as fit by the HerPlaNS data. Squares indicate the measured photometry (with line emission) with vertical lines corresponding to uncertainties. The solid black curve is the best-fit SED (i.e., with line contamination) with T_dust = 36 ± 2 K and β = 1.0 ± 0.1. Crosses show the measured photometry (but line emission contribution subtracted) with vertical lines corresponding to uncertainties. The dashed gray curve is the best-fit SED (i.e., without line contamination) with T_dust = 37 ± 5 K and β = 0.9 ± 0.3.