Extinction (top, with notation of Fig. 12.), albedo (middle), and linear polarisation spectrum (bottom) of HD 37903. The albedo of the dust model of this work (magenta line) and by Weingartner & Draine (2001, dashed) is displayed, together with estimates of the dust albedo of the reflection nebulae NGC 7023 (square) and NGC 2023 (circle). The observed polarisation spectrum with 1σ error bars of this work (red symbols) and as compiled by Efimov (2009, grey symbols) is displayed with the model (black line) that is the sum of aligned silicates (green) and amorphous carbon (orange) particles. Dust parameters are summarised in Table 3.