Imaging Of Solar Active Regions With Fresnel Zone Plates

Photographs of coronal active regions,taken with Fresnel Zone plates were quantitatively analyzed. For this purpose the properties of absorption edge filters used for wave-length selection and of film sensitivity, as well as the imaging properties of Fresnel Zone plates were comprehensively investigated.The separation of the focused +1st order of diffraction picture from the zeroth and -1st order patterns is discussed. We put up the relation between temperature and density in the emitting regions and the energy density distributions in the corresponding pictures, including the effect of chromatic aberration. An iteration procedure was applied to solve the set of equations,which characterizes this relation, leading to two dimensional maps of temperature and emission measure as illustrated for one active region.