Polarization microscope with electromagnet, for imaging of magnetic domains at room temperature and low temperatures. Resolution is 0.5 microns. Samples must be highly reflective and not larger than 20 mm (room temperature) or 8 mm (cooled) across any distance. B-field range is 0-0.3 T (0-0.8 T for samples smaller than 10 mm at RT). Local hysteresis loops can be extracted from image sequences. Field of view is from 65x85 microns up to 1300x1700 microns.