Every astronomical object is polarized to some degree and therefore, astronomical polarimetry gives more information then imaging/ spectroscopy alone. Polarization ie the vector properties of (scattered) starlight depend on the physical circumstances of the location where the light originate. Many properties of scattering dust clouds can be obtained through polarimetry: the sizes, shapes and chemical composition of the scatterers. Even the content, structure and stratification of the atmosphere of some of the stars, planets or exoplanets can, in principle, be characterised without optically resolving them. Another important and unique capability of polarimetry is the measurement of
magnetic fields. Astronomical polarimetry has, therefore, unique capability. In this talk basics of polarimetry along with polarization studies in PRL on a few
different kind of sources will be discussed.