Top: the 110–101 line of H2O at 556.936 GHz observed by (top) SWAS in Sept. 1999 (Bergin et al. 2000). The sub-observer planetocentric latitude is β = −21°. The ~20 km s-1 emission linewidth is primarily caused by the rapid (9.9 km s-1) rotation of the planet. The solid line is the SWAS-derived model for H2O in Saturn’s stratosphere. Bottom: same line, observed by Herschel/HIFI on June 21 and July 8, 2009 (β = −3°) and June 24, 2010 (β = +2°). The orbital longitude of Enceladus on these three dates is 30°, 0°, and 7°, respectively (0° corresponds to the sub-Saturn point being visible at disk center). The insets show a rough sketch of the associated torus appearance.