Illustration of the emergent mean intensity in the SN IIn model at 300d and assuming anisotropic dust scattering. We show the quantity I(p) for the impact parameter p= 0.5 R_max. Two narrow Hα components, due to the dense shell, are apparent, one redshifted and one blueshifted. The component at large velocities (V>5000 km s⁻¹) seen in the inset is due to dust scattering while the component centered on 0 km s⁻¹ is due to ejecta emission.