Measuring Doppler and Magnetic fields simultaneously

Acompact and inexpensive version of themagneto-optical filter, developed in Rome during the 1970s, has attained the capability to measure all the Stokes' parameters on the full solar disk. Without the help of moving parts, each Stokes' image is taken simultaneously with a companion Doppler image. The overall instrument is about 15 15 50 cm in size (telescope included). The working principle of the instrument is described first, then samples of its present applications are given. In this paper we address, for the first time, questions relating to the MOF lifetime and their implications on space applications.