Line of sight from the Sun to the Sgr A Complex at the Galactic centre cuts through a number of spiral arm features, shown in this sketch, which also indicates their approximate radial velocities with respect to the LSR. Assuming that the distance from the Sun to the Galactic centre is 8 kpc, the estimated distances from the Sun to the spiral arm features are as follows: Local – kpc, Sgr Arm – kpc, Scutum Arm – 3 kpc, –30 km s^-1 Arm – 4 kpc, 3 kpc Arm – 5 kpc, EMR – kpc.