The O–C diagrams for comets C/2001 Q4 NEAT (left panel) and C/2002 T7 LINEAR (right panel) for NG model of standard acceleration and all available data (model ALL+STD, see Sect. 3). The residuals in right ascension are shown as black dots and in declination as cyan/grey circles; the moment of perihelion passage is shown by a dashed vertical line, and a dashed horizontal line corresponds to regions where data were taken at small heliocentric distances (r < 3.0 AU).