Position–velocity cut along a position angle of  ~146°. The zero point in the figure corresponds to 02^h03^m21.276^s and 22 02 47.59. The vertical line corresponds to this zero position, and the horizontal line to the velocity that maximises symmetry between the receding and approaching sides of the curve (in this particular cut, 2630 km s^-1). The stars trace the approaching side and the dots the receding side, in order to illustrate the differences between each side.