Modeling specular reflections from hydrocarbon lakes on Titan

► We model the intensity of a glint from a lake or sea, as observed from orbit. ► VIMS observations of a glint from Titan are consistent with a CH4-C2H6-N2 lake. ► We provide an upper limit on the opacity of Titan's polar atmosphere at 5 μm. ► Future observations will allow us to constrain the CH4-C2H6 ratio of Titan's lakes.