The solar seeing monitor MISOLFA: presentation and first results

PICARD is a space mission developed to observe the Sun at high angular resolution. One of the main space objectives of PICARD is to measure the solar diameter with few milli arc-seconds accuracy. A replica of the space instrument will be installed at Calern Observatory in order to test our ability to make such measurement from ground with enough accuracy. High angular resolution observations with ground-based instrument are however limited by atmospheric turbulence. The seeing monitor MISOLFA is developed to give all observation conditions at the same moments when solar images will be recorded with the twin PICARD instruments. They will be used to link ground and space measurements. An overview of the PICARD mission and the solar ground-based experiments will be ¯rst given. Optical properties of MISOLFA will be after presented. The basic principles to measure atmospheric parameters and the methods used to obtain them from solar images will be given. Finally, some recent results obtained at Calern Observatory will be presented and discussed.