Voyager 2 and extended Moses et al. (2018) atmospheric profiles (T_∞ = 800 K for Bates extension) of Uranus. ${\tau }_{\text{sca}}^{1216}$ and ${\tau }_{\text{abs}}^{1216}$ represent the Lyα scattering and absorption optical depths, respectively. When seen planetwards, for Voyager 2/Moses profiles, they reach to unity at the altitudes of 14 200/8500 km, and 184/260 km, respectively. ${\tau }_{\text{sca-Rayleigh only\hspace{0.17em}}}^{1216}$ (not shown in the figure) is unity at the altitudes of ∼180 and 240 km for Voyager 2 and Moses atmosphere profiles, respectively. We do not consider He in our atmospheric models since it is not relevant for Lyα radiative transfer.