The preliminary measurements from the Bolometer Oscillation System (BOS) on board PICARD

The PICARD is a French CNES micro-satellite mission which was successfully launched on June 15, 2010 by the Russian DNEPR launcher. Its objectives are the study of the origin of the solar variability and the relations between the Sun and the Earth’s climate. The duration of the mission is about two years with possibility to extend to three or more years. SOVAP/BOS (SOlar Variability for Picard - Bolometer Oscillation System) is one of the key instruments in the PICARD payload. The main goal of SOVAP/BOS consists in measuring the TSI (Total Solar Irradiance) with very high precision. SOVAP is a new improved version of the DIARAD absolute solar radiometer, which has been successfully installed and operated on several previous missions designed by the Royal Meteorological Institute of Belgium. BOS is a pioneering experiment or to say, a complementary part of SOVAP. It consists of a solar bolometer that measures the incident electromagnetic radiation power by converting this radiation energy in a thermal signal. The radiation is measured using a differential thermometer placed in a thermal shunt. By design, this bolometer is able to measure radiation integrated over all wavelengths and provide a broad dynamic range, with high precision and combined with a fast measuring cadence of 10s, instead of typ. 2-3 minutes in earlier TSI (total solar irradiance) measurements. We will show the preliminary results of measurements made by BOS. For instance, the solar eclipse records during 11, July 2010.