Carina Nebula Sigma 120-300mm

[Nikolas (Nik)]

Used my 183mcPro with my 120-300mm sigma f2.8 and 1.4 teleconverter so approximately shot at 280mm f4

30 x 60second subs no darks Debayered/stacked after much trying using nebulosity 4 and processed in photshopped
Comments welcomed and preferred.

[S_Pettigrew (Suzanne)]

Great photo!

[sil (Steve)]

Very nice, has an overall softness, not sure why. Also looks like faint ring artifacts around stars, a little too much deconvolution perhaps? It may also be why the softness as the rings are almost like antialiasing which reduces the contrast between the stars and the background. I would suggest you could push red vibrancy a touch too. Good shot and you've grabbed some of the lower signal (dim) structure in there without overblowing the core. Its a target that personally bugs me a bit, just so crowded with stars I find detracting from the nebulosity. Hey its there so its there! You have a good balance going at least.

[Nikolas (Nik)]

Originally Posted by sil

Very nice, has an overall softness, not sure why. Also looks like faint ring artifacts around stars, a little too much deconvolution perhaps? It may also be why the softness as the rings are almost like antialiasing which reduces the contrast between the stars and the background. I would suggest you could push red vibrancy a touch too. Good shot and you've grabbed some of the lower signal (dim) structure in there without overblowing the core. Its a target that personally bugs me a bit, just so crowded with stars I find detracting from the nebulosity. Hey its there so its there! You have a good balance going at least.

Yep you are correct I use a plugin called starshrink and I think I took it too far, it is very hard to find a balance. I'm gonna try again next clear night without the teleconverter and see if the image balances out better

[sil (Steve)]

yes its part of the gotchas of ap is most processing adjustments are visual and subjective in nature. That means your eyes, your room lighting, your monitor calibration, your mouse slider skills, your eagerness and boredom all play a role. So its easy for you to overdo something during the stretching of an image as it involves using one tool to improve signal until noise starts interferring and over several tools for making different improvements its often the case that articificial artifacts can multpily with each step and become fully apparent at the end. Often you can easily pick sharpening artifacts and these are the most common that people do.

Its a tricky balancing act at times and you may apply a change so subtle you dont see any difference but know which experience it pays off later. Its all about the end result really. most software has automated tools to improve the image and maybe it gets 95% there, but the careful processing of a dedicated workflow should get you 99% there and careful tweaking at each step a few more 0.1% points. Like choosing an '80s Toyota or a new Audi, both will function as a car and get you from A to B, the toyota is a cheap easy option and is fine but the audi has been built with slightly better refinement in every tiny part adding up to a better choice. Your photo is not crap, far from it. So i'm saying its around the 96% mark just now and to cover the extra 4% will take some time and care in the steps. And to do it without going to 101% (and making things worse) might just be a matter of practice.

Clearly you understand the basics of how and what to capture, so without wishing to insult you, perhaps revisit those steps very closely with what you know now and see if anything can be done to improve each step (adding coolers/warmers/shrouds, tweaking settings, stuff like that. Any tiny tiny thing you can improve at capture pays off in the end (maybe reducing noise a little or being able to capture more signal no matter how small gives you a better data set that can be processed/stretched further). More subs is always a good start even though the gain with each sub starts to diminish it should technically always be there. I stopped chasing multiple targets in a session because I'd rather have the result from 500 subs than just 50. Of course factors impact that capability too, so can those factors be improved/removed? eg more storage space, extra power etc.

Likewise every step you take from capture to final image I suggest looking at, processing steps search for tutorials and articles on your software and each feature you use and see how others use them and maybe how they are explained so you can find hints for adjusting your own. My own workflowis constantly growing and evolving as the software gets new features and I learn more about the existing features. Noting down I find is vital, for example a deconvolution step I might have starting parameters to use along with which parameters I should start adjusting and what to look for in te image or statistics that let me know i'm going too far. That way its in my language so i understand it for next image set. So my workflow would look complicated now to others but for me I feel it works and gets me an image I'm pretty happy with. None of my images are perfect by any means but I try to make each one as best as I'm able to at the time. I think if you know you've put in 100% effort you have to be happy with the result rather than compare yourself to others. Next yar you might revisit the same source set of data and reprocess wity what you know at that point and find a huge improvement using the same captures, thats very satisfying to see for yourself your own improvement.

Specifically with this picture:
Its been years since I used nebulosity so not sure if if can do this. But it looks like your backgound "black" is very grey in this image. See if Nebulosity can tell you how black the blackest pixels are and try to adjust blackpoint down closer to zero. This stretch everything a tiny bit and pin down the black point, white point I say is already clipped so keep that set, then you can adjust midpoint on levels or use curves to start to play with the contrast to push the background grey a nudge towards black (not all the way) and maybe give the nebulosity a chance to pop out from the grey a bit more. Then if you can work on the red channel and see if you can make it a tiny bit more vibrant, tiny saturation maybe but vibrancy is the more appropriate term i think here.

[Nikolas (Nik)]

Wonderful advice Steve
Thank you, it's a new learning (steep) curve for me as I do this only in my spare time and weather permitting.
Considering my earliest attempts a year ago and where it is now it's a large improvement but even here there is a long way to go so I really appreciate everything you have mentioned.
cheers

Edit:
The more I think about it the more I think your advice is invaluable and should be made a sticky.