Optical depth
= Optical depth
{title2=$\tau_\nu$}
{wiki}
Optical depth satisfies $d\tau_\nu=\alpha_\nu ds$ along a path and measures attenuation through $I_\nu\propto e^{-\tau_\nu}$ in the absence of emission.
= Optical depth
{title2=$\tau_\nu$}
{wiki}
Optical depth satisfies $d\tau_\nu=\alpha_\nu ds$ along a path and measures attenuation through $I_\nu\propto e^{-\tau_\nu}$ in the absence of emission.