Observations of HNC(6–5) at 543.897 GHz on Titan measured with Herschel/HIFI. Both H and V polarizations are averaged. 1a) Upper left panel: measurement with WBS (Δν = 1.1 MHz) on June 14, 2010. 1b) Upper right panel: measurement with HRS (Δν = 0.25 MHz) on June 14, 2010. 2a) Lower left panel: measurement with WBS on Dec. 31, 2010. 2b) Lower right panel: measurement with HRS on Dec. 31, 2010. Due to varying distance of Titan, observations on Dec. 31 are scaled in intensity to the conditions of June 14.