This unique interacting system was brought to my attention by an early ESO VLT photo from 1999 (see below). I got immediately fascinated by the galaxy. NGC 6872 is a relatively distant galaxy - it lies about 200 million light years away. Surprisingly it's quite bright at 12^m and relatively big at about 7'. This is one of the biggest known spiral galaxies. Its true size and luminosity are both about 5-10 times that of our Milky Way. NGC 6872 is in interaction with the neighbouring IC 4970.

None of the galaxies have a stellar core. NGC 6872 is brighter and bigger in this respect as well. An inhomogenoius ring is visible in the central part of NGC 6872 that is broken into two parts. These are the two spiral arms. More precisely their inner parts. The outer parts - the tidal tails are extremely difficult. I'm not sure if I had seen them. Especially the Eastern one (to the right). This is longer and broken like an elbow. And on the very edge of visibility. The start of the Western arm was surely visible (to the left) but very faint and difficult as well. We took a look at the system in the 24" Dobsonian two years before the observation. We could see all the details and both tidal tails. They were faint and difficult but definitely visible. In the 16" scope a fainter veil is visible at an angle of about 45° to the main elongated body of IC 4970. This might be the combined effect of a foreground star, the spiral structure and the tidal tail of IC 4970 (?).

Comparison with the photograph

You can see the ESO (European Southern Observatory) photo taken with the 8.2m-es VLT (Very Large Telescope) telescope and the FORS1 instrument to the left. I rotated and cropped my inverted drawing to be able to directly compare it to the photo. The photo covers a slightly bigger area than my drawing therefore there are two triangular areas (top right and bottom left) from where I don't have visual information.