Schematic three-dimensional view of a galaxy with a triaxial bulge and a infinitesimally thin disk. The bulge is shown as seen by the observer along the LOS. The bulge, disk plane, and sky plane are plotted in red, blue, and orange, respectively. The reference systems of the galaxy (x, y, z) and observer (x′, y′, z′) as well as the LON are plotted with thin dotted lines, thin dashed lines, and a thick dashed line, respectively. The axes of symmetry (x_e, y_e) of the bulge ellipse in the sky plane are represented with thin solid lines.