Originally NGC 6621 was assigned to the southeast galaxy, but now it refers to the northern one.

The encounter has pulled a long tail out of NGC 6621 that has now wrapped at the north behind its body.

The side of the galaxy further from the companion features noticeably less star formation activity.

When observed in H-alpha, the centre of the galaxy has two bright sources separated by 3 arcseconds, with the southwest being brighter while the northeastern one coincides with the nucleus of NGC 6621.

18), was discovered on 1 September 2010, lying 30" east and 4" north of the center of the galaxy.