Intensity profiles in the north polar coronal hole, along the UVCS slit for six heliocentric distances. Intensity profiles of the redundant H I Lyα are shown as black solid lines. The O VI 1031.9 and 1037.6 doublet intensities are represented by red and blue solid lines, respectively. We limited the sample of our data to the observations performed on the 6 and 7 April, with the slit center covering heliocentric distances up to 1.85 R_⊙. The abscissa axis reports the polar angle latitude in degrees (upper axis) measured counterclockwise from the north pole, and the corresponding detector bins (bottom axis).