Prompted by a recent paper by Dima and Schad, we re-consider the problem of inferring magnetic properties of the corona using polarimetric observations of magnetic dipole (M1) lines.

We consider the vector emissivity of the polarized radiation transfer in a Lambda-type atomic transition, which we recently proposed in order to account for both CRD and PRD contributions to the scattered radiation.

We investigate the application of 2-dimensional Principal Component Analysis (2D PCA) to the problem of removal of polarization fringes from spectro-polarimetric data sets.

Roberto Casini et al report on the measurements of the vector efficiency of a reflective blazed diffraction grating, which was specially coated in order to reduce the level of polarization in the diffracted light.