Abstract
We present polarimetric observations in the UBVRI bands of stars located in the directions of NGC 3603, Westerlund 2 and Sher 1. Our main objectives are to study the characteristics of the dust lying between the Sun and the clusters, to analyze polarimetric evidence on the existence (or not) of abnormal reddening in NGC 3603 and Westerlund 2; and to identify stars with signatures of intrinsic polarization. 40% of the stars observed in Westerlund 2 display indications of intrinsic polarization, a percentage similar to those found in the open clusters NGC 6611 and IC 2944: but in NGC 3603 it is very small. Mean polarization efficiencies are low, due to the presence of several dust clouds located in the way to the clusters. We are in favor of the existence of abnormal reddening in NGC 3603, while in Westerlund 2 there are only indications.
