I am sorry all.....I inadvertently deleted this image so this is my attempt to restore it. I have slightly pulled the green down in the image and in trying to get the mouse over working I deleted everything. Don't feel you need to comment again if you've already done so. This time I include a couple of illustative pictures.
This image has been a long time coming. I last published an image on AstroBin in mid January. I have wanted to image The Antennae Galaxies for a very long time and so I decided to start early in the appartion. I have been capturing data since the end of January and at last have completed the image. In fact, I captured the data in two lots, with 23 hours integration for the first and 18 hours for the second to give a total of 41 hours. 
I had some challenges with the image processing for the first lot of data and felt that more data might help overcome those and give me a higher SNR.
The challenges I had with the processing the first tranche of data were gradients in the MasterStacks, red/pink halos around the stars and a very blotchy background.
I had used the Weighted Batch Preprocessing script in PixInisght for the first time in earnest. The script is great once you have eliminated defective subs, but it incorporated a new process for the integration called Local Normalisation. I suspected that might be an issue and sure enough after I unticked the box to eliminate it, the gradients I had seen in the MasterStacks disappeared. Here is the RGB Combination without the Local Normalisation (left) and with at right.

I blinked the RGB MasterStacks and realised that FWHM for the Red was substantially more at 2.5 arc secs, than the Green (1.9 arc secs) & Blue (2.1 arc secs). This caused the coloured halos. I did work out a method with Deconvolution to equalise the FWHMs and this worked well but I didn't ended up needing to use it. When I included the 2nd dataset, the FWHM values were much closer and the problem was eliminated. In this 2nd dataset, the Red FWHM values were better and the Green and Blue worse, such that they balanced out. Ironically it was the excellent seeing that I had for Green and to a lesser extent Blue, that caused the coloured halos in the first place. Neverthless I was not aware that, for my image scale of 0.5 arc secs/ pixel, it is important that the FWHM values not be too different, lest coloured halos be created. For those astro imagers with larger image scales this is unlikely to be a problem because the sampling controls the resolution and the FWHMs registered. Across the capture of this dataset I had very variable seeing conditions, which allowed me to see the difference that seeing makes to resolution of detail. Revision D is a complilation of Luminance images, showing the central interacting parts of the galaxies. The 10 images range from 1.7 arc secs to 3.9 arc secs and show the huge effect on resolution. Based on this I now reject images where the FWHM values are greater than 3 arc secs.
I have been having problems with blotchiness in the background of my images for some time. This has meant having to darken the background more than I would like to hide the issue. This time the problem was untenable, and I decided to go back to each step in the process to see where the issue was arising. After each step I made an RGB Combination and examined the images for blotchiness. I discovered that the problem stemmed from the Mure Denoise script that I had been using to do noise reduction at the Linear stage. The image at left is without the Mure Denoise and at right with. After I dispensed with the Mure Denoise, the problem was eliminated and I relied on Jon Rista's denoising processes to effect the denoising, without creating the issue.

Now to the target itself.

The fabulous Antennae Galaxies. We see two galaxies in the midst of their collision and merger. Their interaction has thrown out two long stars streams that give the object its name. It is also known as Arp 244, and is part of Halton Arp's Atlas of Peculiar Galaxies.
They are about 45 million light years away in the constellation of Corvus, the Crow.
Apparently about 1.2 billion years ago these were two separate galaxies, and NGC 4038, the one with its core uppermost and star tail downwards in the image, was a barred spiral, whilst NGC 4039 was a conventional spiral. The extent of the interacting pair is purported to be 500,000 light years, so I imagine the two galaxies started out around the size of our Milky Way galaxy at 100,000 light years across.
900 million years ago they approached each other, drawn together by their mutual gravitational attraction, such that 600 million light years ago, the cores passed through each other. About 300 million years ago, streams of stars were thrown out of each of the galaxies forming the amazing tails we see today. As the two galaxies came together, the huge gravitational disturbances caused hydrogen clouds to interact and collapse causing massive star formation. The red glow of Hydrogen Alpha, shows where these star forming regions are located. Interestingly there have been 5 supernovae discovered in the two merging galaxies between 1921 and 2013!!…...: SN 1921A, SN 1974E, SN 2004GT, SN 2007sr and SN 2013dk.
Clearly the very active star forming regions are producing massive blue, white stars which live out their short lives before exploding as supernovae. Remember that the last supernovae in our more quiescent galaxy the Milky Way, occurred 400 years ago.
It is interesting to compare the resolution achieved with a modest 35.5cm diameter telescope through the atmosphere with the HST with its 2.4m diameter mirror above the atmosphere...Revision D. It is pleasing to see how well they correspond.  Clearly the resolution of fine detail is far superior in the Hubble image. I have also indicated the position of the galaxy cores, which retain their nice yellow colour from older stars there. They are being stretched and sundered by the collision.
How thrilling to see this collision, as if frozen in time, before us......and yet we know the collision process continues all the time and will do so for a couple of billion years more as the two galaxies merge to form a larger elliptical galaxy.