Maps of the Doppler shifts (in m/s) measured in the core of the CO(1–0) lines, for different observing dates. Regions where Doppler shifts could not be retrieved appear as blank. In each panel, Venus’ disk is represented by the centered circle, the synthesized beam by the ellipse in the bottom left-hand corner, and the terminator by the vertical arc. The contour step corresponds to 20 m/s. The maps were rotated to ensure that the pole axis is vertical in the figure. Top panel: 2007 observations (merged data from the two observing dates). Doppler-shift errors are on the order of 25–35 m/s on the day-side and 15–20 m/s on the night-side. Middle panel: June 12, 2009 observations. Errors are on the order of 10 m/s on the day-side and 6 m/s on the night-side. Bottom panel: June 13, 2009 observations. Errors are on the order of 15–22 m/s on the day-side and 7 m/s on the night-side.