Orientation of the linear polarization plane of H-alpha emission in prominences

2D distributions of deviations of the polarization plane from the direction tangential to the solar limb (angle \chi) and the sign of \chi are presented for H{\alpha} prominences of March 29, 2006. The obtained values of \chi are in agreement with non-eclipse coronagraphic measurements and indicate the existence of longitudinal magnetic fields. The 2D distributions of the sign of \chi show the existence of both {\guillemotleft}+{\guillemotright} and {\guillemotleft}-{\guillemotright} polarities for each prominence. An interpretation in the frame of the existence of oppositely directed magnetic fields is noted.