[RCC] 20 hours of Iris Nebula

A quick fix for the magenta colour cast is to invert the image which will turn the magenta green, apply SCNR, then invert the image back again. This will give you a nice neutral result to work with. Another thing I'd experiment with is Contrast Limited Adaptive Histogram Equalisation or whatever it's called in Pixinsight, just a tiny amount will improve the contrast and enhance the details. Hope this helps!

I use LocalHistogramEqualization (LHE) to enhance dark gas detail.

andrea tasselli:
I'd control the amount of stretching to tame the noise and also try to suppress the amount of purple-ish fringing you got.

Mina B.:
Hey thanks, should I invert the image in the linear stage?

GraXpert is cool and all, but in a dusty situation like this you will want to judiciously apply DBE yourself. By "judiciously" I mean fine tuning the locations of your DBE points will be one of the largest parts of your processing flow.

You can hunt down images with crazy integration times to get an idea of where there is and where there is not dust in your FoV. You can also run DBE on your image, and based on the results go back to the original and keep fine tuning the points.

Mina B.:
Hi, this is my longest integration so far, and I really really wanna make the most out of the data.

My workflow, due to cone error was like this:
1) stack all subs that were good (639) and do another stack with just the subs before the meridian flip
2) GraXpert on both
3) then in PI on both: Background Neutralisation, Spectrophotometric CC, SCNR, MMT on Chrominance Noise with Mask applied, BlurX, StarX on both.

Then I kept working on the starless 20h Nebula and the stars which were only around 10 hours I'd guess.
Starless:
4) NoiseX
5) Multiple Stretches with GHS
6) Cloning Image, applied HDRMultiscaleTransform on the Nebula Core
7) Added with HDR Nebula with the regular in Pixel math, weighted 40 HDR, 60 Regular
8) Some Curves Transformations for Saturation / Contrast with Mask
9) Another Round of Background Neutralisation because it was way too blueish / purplish

Star-Stack:
Stretching and Saturation slightly inscreased.

Merged both images with Pixelmath: combine(Starless, Stars, op_screen())

Please give honest feedback, Image can be found here: https://www.astrobin.com/n2apl4/


Thank you and Clear Skies!

Andre Vilhena:
I think the overall result is fine, albeit you can do some adjustments like other people is mentioning. However, there are some things you could change in your work flow that I am sure it will help:

1) For heavily filled FOV like yours, I would ditch any automated tool to remove gradients and would use DBE. You have several spots to place samples which should deal with the gradients (assuming they are not horrible) - remember that some regions might have nebulosity but it is so faint that you cannot make anything useful out of it and therefore should be treated like background;

Mina B.:
under Bortle 3 skies

Mina B.:

BryanHudson:
There's nothing that can be critiqued, certainly not by anyone who has not done comparable work––something I check when receiving advice. One of my mentors used to say. "If you don't know, don't help me."
 It is an exceptional image technically and stylistically! Well done!

Oh and thanks, that's very kind! But I'm sadly never quite content with an image. I'm glad for all the helpful tips I got here though.


Yes, the nature of this hobby is that we are never satisfied! 
That is likely a little bit of motivating OCD. :-)