Based on a recessional velocity of 8720 km/sec, NGC 6150 is about 405 million light years away. Given that and its apparent size of 1.3 by 0.65 arcmin, it is about 150 thousand light years across.

Based on a recessional velocity of 9535 km/sec, PGC 58100 is about 445 million light years away. Given that and its apparent size of 0.7 by 0.3 arcmin, it is about 90 thousand light years across. Although peculiar (non-Hubble expansion) velocities could be responsible for the difference in recessional velocity between PGC 58100 and NGC 6150 (which see for images of the pair), their lack of any obvious gravitational interaction suggests that the smaller galaxy truly is a background object, and not physically related to its apparent companion.

NGC 6188 is an emission and reflection nebula to the west (right) of a very young association of stars, NGC 6193, which is heating and lighting up the eastern (left) side of the nebula. The nebula (and cluster) lies about 4000 light years away, so the 30 arcmin wide image directly below covers a region about 35 light years across. As can be seen in the wide-field views of NGC 6188 and 6193, most of the clouds of gas and dust in the region are relatively cool and dark. The region being fiercely heated and sculpted by the radiation from the nearby cluster of stars is also referred to as RCW 108.

An OB1 association (a group of extremely young stars, at most a few million years old, which therefore includes some extremely hot, bright stars) which is heating and lighting up the gas and dust surrounding it, especially the emission and reflection nebula to the west (right) of it listed as NGC 6188. Most of the radiation heating, sculpting, and compressing the nearby clouds of gas and dust comes from the bright object near the center of the cluster, which is actually a binary star consisting of two extremely massive, extremely bright O-type stars. The cluster and nebula lie about 4000 light years away, so the 12 arcmin image below covers a region about 14 light years across, and the 30 arcmin image covers a region about 35 light years across. As can be seen in the wide-field views of NGC 6193 and 6188, most of the clouds of gas and dust in the region are relatively cool and dark. The region being fiercely heated and sculpted by the radiation from the nearby cluster of stars is also referred to as RCW 108.