Velocity field obtained over the Musca filament crest from the C¹⁸O(2–1) line in the northern (top) and southern (bottom) map. The contours indicate the column density levels of the filament crest ( 3–6 × 10²¹ cm⁻³). The black line on the velocity field connects the maximal column density at the top and bottom of the map, indicating the local orientation of the filament axis. In the lower left corner, the red arrow indicates the orientation of the velocity gradient, while the black line indicates the orientation of the magnetic field.