Calculated and reference opacities of astrophysical dust, plotted as a function of the wavelength. Dashed and dotted grey lines labelled with OH94 refer to bare grains and dust grains with icy mantles employing the optical properties described in Ossenkopf & Henning (1994), respectively. Opacities for grains with pure H₂O icy mantles at different temperatures, computed for optical constants of the present work at different temperatures, are depicted by solid lines.