Schematic view of the the bar and spiral arms of the Galaxy at the present time. The blue bullet marks the current position of the Sun measured in an inertial system that is fixed at the center of the Galaxy. The axes X_rot and Y_rot correspond to a system that corotates with the bar. We note that the spiral arms start at the edges of the bar, and the coordinates (X_rot1, Y_rot1) and (X_rot, Y_rot) overlap at present.