HELP missing andromeda colors.

Hello,

in a nutshell, this is the color that I was able to get out of the original image. (Software used are APP, PI and PS)



However, this version doesn't look natural because the color saturation has been maxed out quite a bit. There are no data in Ha and OIII to be able to show the special color of Ha and OIII in M31.
Unless the recording camera is astro modified it will be "red blind" anyway so the Ha line will always be underrepresented.


Kind regards, Markus

Hello,
here is my procedure for this image:

1.)  APP  batch crop
2.)           remove light pollution
3.)           calibrate star colours
4.)  PI     BlurXTerminator
5.)           ChannelExtraction
6.)           LinearFit (green)
7.)           ChannelCombination
8.)           MaskedStretch
9.)           SCNR (75% green)
10.)         NoiseXTerminator
11.)         StarXTerminator
12.)         LHE
13.)         Curves
14.)  PS  Camera Raw Filter -> "Farbmischer" (in german)   (actual color saturation)
15.)  PI   stars reinserted (PixelMath)

APP = Astro Pixel Processor
PI = PixInsight
PS = Photoshop

I wish you success!

Here my colours > https://www.astrobin.com/e8sr90/G/?nc=&nce=

Here my steps after stack in Pix

- i remove the stars with StarX
- DBE in the starless with "normalize" on
- i put the stars in the starless 
- Spectrophotometriccolour calibration with mine parameters (filters, sensor)
- noise reduction
- Hyperbolic stretch
- saturation

Hi Hassaan,

Here is my take on your image file. I assume this is the type of colour you are trying to achieve?



The data isn't bad however there are a few things that can be improved on that will make it easier to edit. Firstly, I noticed there was some walking noise, are you dithering? If not, I recommend dithering if you can, as walking noise is notoriously tricky to remove in post-editing. There were also some weird artefacts in the image, which could be removed by applying flat frames. That being said, I have managed to remove them during editing.

It's been cloudy for ages in my location so I took this as a small editing exercise, and I'll break down how I got to this final image below. Apologies in advance for the long post!

Please Note: I am using PixInsight, RC-Astro Plugins and Affinity Photo (a Photoshop Alternative). While you can get decent results using PS alone, PixInsight and the RC-Astro plugins make a substantial difference.

Step 1:

Background Extraction. I found DBE offered a much better result, even with the leftover gradient. To achieve this in Affinity Photo there is a gradient removal tool, and I assume there is a similar alternative in Photoshop (Astronomy Tools).

Please bear in mind you will have to process step 4 first if using Photoshop and come back to these steps.



Step 2:

Colour Calibration. This is a process in PixInsight but it can be duplicated to some extent in Photoshop/Affinity by adjusting the RBG levels until they are in line with each other.


Step 3: 

Convolution & Denoise. I used RC-Astro BlurX and NoiseX here, which are game changers in terms of the results they produce. It tightens the stars, brings out more detail in the galaxy and removes the harsh noise (except walking and heavy colour noise - more on this below).

There are some free tools for Affinity by James Ritson which offer some simple convolution processes, but I'm not sure about Photoshop. Noise reduction however will be present in both.


Step 4:

This is after stretching. In Photoshop/Affinity you will need to do this first as the raw image will have little-no details present. You can do this by performing levels and curves adjustments.


Step 5:

Star removal. I removed the stars to process the galaxy separately. I used StarX, however, you can use Starnet++. I applied some slight saturation to the stars to bring out more of their natural colours and performed some star size reduction.


Step 6:

I created a mask to only affect the galaxy and not the background.


Step 7:

From here, I applied the following:

• Unsharp Mask
• SCNR
• Contrast Curve
• Saturation Boost
• Colour Curve Adjustment
• Dark Structure Enhance
• Final Noise Reduction Pass (to compensate for sharpening)

The result was the following:



Step 8:

In Affinity Photo I made some final touch-ups. 

First, I used the inpainting tool to remove the artefacts from the image.

I then applied an exposure adjustment a few stops down to decrease the brightness. I then applied a gradient to this effect in the bottom corners to reduce the lingering gradient in the image.

To help reduce the walking and colour noise, I added a noise reduction filter affecting the colours only. I then added a gaussian blur to the image but masked the galaxy so it wouldn't be affected by this. This process helped to smooth out the background and level it off somewhat.

To add some yellow colour to the centre of the galaxy, I applied a luminance mask to a white balance adjustment. I set the mask to only affect the brightest part of the galaxy in the centre and set the white balance on the warmer side until I was happy with the colour.

Finally, I added the stars back over the top using the screen blend method (you can use add but I prefer the subdued look of screen).

That's it!


Please give the above tips a go, I'm sure you'll be able to make a fantastic image. If the colours are your primary concern, then it's quite easy to manipulate them using luminance and hue masks to affect certain parts of the image.

I hope this helps!

Clear Skies,
Kieran

@Kieran Gunessee Thanks for you update the image is extremely sharp. I do not dither because i use a star adventurer.

Hassaan Zaheer:
@Markus Gorski Heres my new attempt with your work flow and i am amazed at the results. Hats off

Hello,
that looks good.
Be careful not to create artefacts and color breaks. This happens when each setting is pushed too far, or when a single color becomes too saturated. Less is usually more.
I would also try the other suggestions made here and find my own way.
Best regards