The Antennae Galaxies (NGC 4038 & 4039) are merging galaxies in Corvus. This is one of the places in the universe where you can see the steps in the gravitational dance all celestial bodies are performing. Granted we can only see this one step and it’s not likely we’ll see any visible change in our lifetimes but over the next few tens of millions of years these two galaxies should merge into a giant elliptical galaxy.

For now we get to enjoy the graceful tidal tail arcs and see the chaos in the main bodies of the galaxies. According to most references these galaxies are about 45 million light years away so it is likely that the light just leaving the galaxies now and due to arrive here in another 45 million years would show us that completed merger.

This is 21.25 hours of LRGB data. For all the technical details, see astrobin.