Comparison of the original CERES pipeline with the adapted pipeline. Top: spectrum of the B9V star HD 33244 reduced with the original CERES pipeline. Red and purple arrows indicate the positions of wiggles and a gap, and yellow circles show the positions of some bumps (see the text for an explanation of these features). Bottom: spectrum of HD 33244 reduced with the new version of the CERES pipeline that includes the four changes described in Sect. 3.