Only relative photometry was made since the air mass was very large most of time. The sky-background was carefully recorded several times, especially during daylight in order to be eliminated. When possible, the flux of a reference object was recorded (a star or, most of time, another satellite which is acceptable because of the short duration of the events). This made possible the observations even when small clouds or fog were present. Figure 2 (click here) gives an example of a complete reduction using the sky-background and a reference object for an observation made at Meudon Observatory during twilight with some light clouds in front of Jupiter (cf. Sect. 3). This observation has been made using a CCD target in video mode. The final lightcurve demonstrates the power of a two-dimensional sensor which records the sky background and a reference satellite at the same time as the occulted or eclipsed satellite. The determination of the date of the minimum of light and of the value of the magnitude drop was obtained from a fit of the lightcurve with a sample polynomial. The errors on these determinations are also given.