Westerlund 1
Wd1 is too far away for direct measurement of the distance by parallax measurements, so the distance must be got from the expected absolute magnitude of the stars and estimates of the extinction towards the cluster. This has been done, giving estimates of 5 kpc and 3.6 kpc by different methods. These estimates all place Wd1 near the outer edge of the Milky Way's galactic bar.