Figure 2. Plots of the magnitude and direction of the polarization induced by the reflection from the aluminum mirror, as a function of angle of incidence. The measurements are represented by circles and are plotted with their associated horizontal and vertical errors. They have been corrected for a systematic offset in the polarization as described in section III. In the upper plot, the dashed curve represents the theoretically predicted magnitude of the polarization, and a best fit polarization magnitude is shown in the upper plot as a dashed curve. In the lower plot, the polarization angle 0 degrees corresponds to the (theoretically expected) vertical direction. A description of the fitting technique used to determine the systematic offset and best fit curve appears in section III.