HCG 93 "Finished"?...

[DaveS]

...Or not? I dunno.

This is 6 hours Bin 1 Luminance and 6 hours Bin 2 RGB, all at -26C and 600 sec subs captured, with the ODK 12 and SX 694 through Baader filters. The RGB was captured on the 7th October and the Luminance on the 14th. I waited until I had my main PC with PI and the RC tools back from repair, and been fighting with it for 4 days now but decided to post anyway

My main concern is in NGC 7549 (Top centre) and whether the structures shown are genuine or a deconvolution artifact. I'm still not sure. I'm also concerned that I've blown out the galaxy cores. Don't care about the stars, they will blow out anyway.

In any case, here it is, please take the time for any constructive criticism.

 

[Neil_104]

Nice image - lots going on! I'd be inclined to try to increase the contrast a bit & to try to darken the background a little to make the galaxies themselves stand out more. There's quite an un-evenness in the background and reducing this would make it less of a distraction for me. If doing this reduces the excellent tidal distortions you've captured then more imaging time it is! Overall though I really like it - it's nice to see something a little different rather than yet another image of M31 (like I've just done 😆). Not in any way being negative here - just how I see it 👍

[DaveS]

Thanks Neil, yes I think it needs more (Careful) work on the background. More data always helps but there's already 12 hours in there and with our rubbish weather a decision has to be made as to whether to capture more data or move on to the next target. This is part of my project to image as many of the Hickson Compact Groups as I can. This is the fourth that I've got into a nearly finished state, out of a catalogue of 100, so a way to go yet.

Edited November 12, 2023 by DaveS
Capitals!

[Neil_104]

Ah I see - bold project to attempt, love it! In that case I think I'd probably be more inclined to give it a few tweaks with the processing (even if only adjusting via something like camera raw in PS) and then move on. It's not like you've skimped on imaging time so far!

[tomato]

I’ve attached a rough library image of the group, the structure in NGC 7549 is definitely there, and you have captured more faint outer structure than appears in the library photo.

The background is more uneven in your image but I wonder have you gone deep enough to capture any IFN in this region? 
 

Either way, respect for capturing this target under our hopeless UK skies.👍

[gorann]

Looks very promising and a bit more processing may be what is needed. I see a blue cast here and there and especially between the main galaxies that maybe should not be there. Maybe also try another does of NoiseXT?

Edited November 12, 2023 by gorann

[DaveS]

Thanks all.

Yes, I will revisit this after taking a short break to allow my eyes to recover.

One slight possibility is to capture more data while waiting for the next target to get high enough.

[DaveS]

And to add that the blue cast has been bugging me too, most likely in the RGB layer. More data, more better 😀.

[gorann]

Since I am clouded in I could not stop myself from playing with your image in PS. Only did two things: a dose of NoiseXT and then tweaking the blue curve on a starless image (StarXT) to suppress the blue cast. I hope you do not mind. However, more data would improve it since I noticed that any further stretch brought out quite a lot of noise.

CS, Göran

[DaveS]

Thanks Göran. There's a very useful tool in AstroArt 8 for attenuating a single colour using level and range. I think I will give it a go on Blue.

[DaveS]

Well, the faint blue excess was too close to other detail for Attenuate Singe Colour, but I had another play with it, giving the RGB layer a stronger Noise X in PI plus a bit of Histogram Stretch on the finished LRGB amd a masked Saturation Boost on NGC 7549. I may leave it here as I think it will be "good enough" for my project.

[gorann]

Looks great Dave so you can with good conscience move on to your next project!

[Neil_104]

Nailed it 👍