Stephan and Deer, now with more data

[DaveS]

I managed to capture some more data on this, so now 30 subs each R, G, B (In G2v calibration) totalling 18 hr 45 min and 72 subs Luminance totalling 12 hr. not sure at the moment how much ended up in the final stacks as I had AstroArt reject subs with elongated stars, fuzzy stars (High FWHM) or high sky background.

The Luminance stack was cropped to remove alignment edges followed by Gradient Removal and DDP with a "soft" High Pass" setting and Richardson Lucy Deconvolution.

The RGB stacks were brought into the Trichromy process and aligned before being cropped and the RGB channels separated for gradient reduction. Again a "soft" High Pass DDP was applied followed by Richardson Lucy deconvolution. Close attention was applied to the histograms during this.

The individual RGB stacks were now brought back into Trichromy before being Coregistered with the Luminance. Several rounds of Histogram Stretch followed to bring the range back to 16 bit before Colour Curves were applied to bring out the Core / Arms difference. There was an Unsharp Mask in there somewhere and a final Histogram Stretch just to bring up the background a touch.

Phew! And I'm still not happy. There are some dark halos that are proving troublesome while still enhancing the detail.

C&C welcome, together with any suggestions as to how to proceed from here.

[MartinB]

The galaxies all look terrific Dave and welll worth the effort you have put in.  You only see the star artefacts when you zoom in too much! 

[DaveS]

Thanks Martin.

Still looking at this with a view to bringing up the star colour without trashing everything else. Also experimenting with some of the tool settings in AA8 in an effort to be more subtle in the processing.

[DaveS]

I've been having another play with the data.

From the individual coregistered channels I applied an Erosion filter to reduce the star sizes, followed by a more careful DDP with attention to the star cores and a Richardson Lucy deconvolution using a Gaussian Kernel. After RGB synthesis I applied the Luminance I had worked on earlier to produce a LRGB image. A mild saturation boost was followed by a single colour attenuation to remove a touch of excess green followed by a mild Unsharp Mask.

I dunno. I still think I'm going round and round the bullseye without quite hitting it. I have so many versions of this it's making my head spin. It's proving very easy to blow out the star cores or blow out the galaxy core or end up with "Cartoon Colours" in NGC 7331.

Going to take a break and come back in a day or two, but if anyone has further suggestions I would be grateful.