A new method to detect active features at the solar limb

In the framework of the future PICARD micro-satellite, where one of the main goals is the precise determination of the solar shape, we developed a new method of detecting features at the solar limb, such as active regions (sunspots and faculae) or supergranulation. This method is based on the analysis by means of the Singular Spectrum Analysis of two signals: one coming from the analysis of the distance between the center and the inflexion points of the limb profiles (called `radius') and the other one concerning its intensity (called `intensity'). To test this method, we have developed a new instrument, called MIRESOL, dedicated to the detection of magnetic features at the solar limb. In a first section, we will present the necessity of such a method; in a second part, we will briefly describe the MIRESOL instrument. In a third part, the algorithmic description of the method is applied to images taken with the MIRESOL apparatus and an example is also given using a PSPT image. The last section is reserved for commenting on perspectives concerning the development of a space and ground-based synergy.