Formation of the FeI 5324.19 line in the sun and theoretical calibration of solar magnetic telescope

Using the Unno-Beckers equations and the Rnnge-Kutta method with variable steplength, we calculated the formation in a magnetic field of the FeI λ 5324.19 line in the solar photosphere, sunspot penumbra and umbra, and determined various theoretical calibration parameters for the magnetic and radial velocity fields. These parameters for the transverse and velocity fields have good linearity and stability and adequate sensitivity, making the line very suitable for the study of solar active regions. When observing the transverse field, the filter should best be placed 0.10 – 0.11 A away from the line centre. The calibration is rather complicated when magneto-optical effects are considered. Temperature sensitivity effects of this line should not be serious.