Hi
This bit of Abell S0636 is a beautiful cluster with two major (and similar) ellipticals apparently attracting a varied range of smaller galaxies. The scene appears to have a slight, misty local reflection nebula, apparently illuminated by the bright foreground star cluster and presumably also by integrated flux from elsewhere. There is also a little background redness in places, about where Rolf identified a weak SN remnant. Also, if you toggle to full res, there is a spatter of tiny pale orange dots at about 8 o'clock to the rightmost big elliptical - looks to be a background galaxy cluster at a vastly greater distance.
antlia cluster (you can toggle to full res in top right corner of the page)
I arranged the composition based on the galaxies, but it has been thrown out of harmony by the reflection nebula - which wasn't readily visible until I stacked. Oh well, this is what it is
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if interested, lum 177x300s 1x1, R 67x180s 2x2, G 30x180s 2x2, B 50x300s 2x2. Minimal processing (colour balance on foreground stars, deconvolution, stretching, slight colour tweak)
thanks for looking. regards Ray