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1.5.2 Geographical and time coverage

Besides the self-calibration and the good vertical resolution, the advantage of the stellar occultation method is the excellent global coverage provided by the multitude of suitable star targets. A typical weekly coverage is shown in Figure 1.4 and Figure 1.5 (historic and recent maps can be found at Until early January 2005, the daily number of measurements was about 400. The nominal measurements were then stopped, because of a failure in the telescope rallying drive. They resumed in July 2005, but with a reduced daily total number of measured occultations estimated to be about 280.

Figure 1.4: Example of geographical coverage of GOMOS measurements (measurements planned between 6 and 13 April 2004). The colour code for each occultation corresponds to the star ID.

Figure 1.5: Example of geographical coverage of GOMOS measurements (measurements planned between 7 and 14 April 2007). The colour code for each occultation corresponds to the star ID and its magnitude.

The variation of the latitude-longitude coverage with the obliquity for each occultation is illustrated in Figure 1.6 .

Figure 1.6: Area probed by occultations planned between 7 and 14 April 2007 and highlighted by occultation obliquity range.