IKO - NGC6888 Crescent Nebula SHO - Processing Competition

[Grant]

We've just released another set of data from the Ikarus Observatory project here.

Following the wonderful entries from the first processing competition we are running another to see who can get the most from this data and create the 'best' image! The winner will receive £150 of First Light Optics gift vouchers and two runners up will receive £50 of gift vouchers.

Details below:

• Closing date: 31st December 2023 @ 22:00
• Please post your entries into this thread
• Please only use the data we've released - don't blend it with other data or add to it with other sources
• Use what ever processing software and techniques you like, potential bonus points for sharing your workflow and techniques with others - that way, we all get to learn as well 
• Multiple entries are allowed but, please refrain form posting multiple attempts that are very similar - better to update an earlier attempt if it's just an incremental improvement but, it would be interesting to see totally different attempts using different narrowband blends etc...
• If you win or are a runner up, we would really like to use your creation in future marketing materials, on our website etc.. so by entering the competition, you are giving us permission to use your image in this way.
• Judging will be done by a small team of judges from the FLO team - It's completely subjective  but will be based on what image(s) we think do the best job of extracting the most from the data released and, look the 'prettiest' 
• We will announce the winners in early January via SGL

Thanks all and look forward to seeing your entries!

[WolfieGlos]

I'll start this one off then!

That's some incredible data, a pleasure to work with so thanks to the IKO for sharing it. It might even convince me to get not only an astro camera but mono at that......

So here's my *first ever* mono processed image, processed as SHO.

I decided not to crop or rotate the image, it looks to me like it's a hand of god juggling the crescent for fun. Stars were a problem in the corners and the right-hand side, so I tried to rectify them as best as possible. Processing details below.

Processed in Siril, Starnet, Topaz and GIMP.

Pixel Math R=(0.35*Ha)+(0.8*SII), G=(0.4*Ha)+(0.6*OIII), B=OIII
Asinh Transformation: (stretch=1000.0, bp=0.00000)
Histogram Transf. (mid=0.092, lo=0.022, hi=1.000)
Save as Tiff file. Run through Starnet V2 Standalone.
Open Starless Image in Siril
GHS SAT pivot: 0.122, amount: 2.54, local: 0.00 [0.00 0.69]
CLAHE (size=4, clip=1.00)
Wavelets Transformation (2, 1.5, 1.5, 1.5, 1.5, 1.2)
GHS pivot: 0.153, amount: 0.35, local: 0.30 [0.00 0.81]
Cosmetic Correction
Open STARLESS IMAGE IN GIMP
S-curve to background
Colour temperature adjustment to a warmer image
Duplicate image, apply contrast boost. Black mask and brush in Soap Bubble, gaussian blur to blend in.
New from Visible. Sharpen Boost, default settings at 54% opacity.
EXPORT TO TOPAZ DENOISE. Standard model, 100 / 85 / 61 / 100
STAR PROCESSING
Open Starless and original stretched image in GIMP. Use subtract mode to acquire stars image.
Duplicate stars image, and using GIMP Astronomy Plugin (Georg Hennig: http://www.hennigbuam.de/georg/gimp.html ), use filter for Round Stars to change angles in left corner. Black mask, and brush in.
Repeat for the other 3 corners
Create "New from Visible".
Copy layer into STARLESS NOISE-REDUCED IMAGE, blend mode of Screen
For the star layer, apply slight curve enhancement for brightness

[Richard_]

NGC 6888 in HOO Palette

Processed entirely in PixInsight using various addons. I used a very similar workflow on this data as I did for the same target using my own data with some minor changes. It was nice to compare the images side by side after all the processing was done, and noticed how similar they are

See the picture below followed by a brief overview of the workflow I used. All addons are listed below and I have provided the source for others to access them, some are paid (£) and some are free.

Workflow

Software: (£) PixInsight 1.8.9-1 Ripley

Add-ons: (£) BlurXterminator, (£) NoiseXterminator, (£) StarXterminator, (Free) Narrowband normalisation, (Free) Star Reduction, (Free) GAME

Workflow

• Star align H and O master lights and crop out any stacking artifacts
• BlurXterminator and NoiseXterminator on H and O master lights
  • "Correct first" ticked
  • Corner stars in each sub had bad artifacts, so oversharpening stars just brings attention to these
  • Kept "Sharpen Stars" and "Sharpen Non-stellar" lower than default settings
  • Not much denoising was required, so kept the values below default
• GHS on the H and O master lights separately
  • I like to do this to control the amount of contrast in each channel
  • I adjusted the histograms until the peaks are roughly at the same point
• PixelMath
  • R -> H
  • G -> O
  • B -> O
• StarXterminator to remove stars
  • Tick "Generate Star Image" and "Unscreen Stars" to allow you to add them back in later
• Narrowband Normalisation
  • Unconventially, set source to "SHO"
  • Adjusting SII slider in this mode controls the balance of H
  • Focusing on the crescent, adjust SII and OIII sliders until I was happy with the colour balance
• GAME script
  • Create a mask to cover the soap bubble (which can be seen top right of the Crescent in my image)
  • Apply mask and invert to protect the background
  • Using GHS, boost histogram ever so slightly, just to accentuate the features of the soap bubble without making it look out of place
  • Remove mask
• Curves transformation
  • Focusing on the surrounding nebulosity, slight boost to red histogram to taste
  • Boost overall saturation in RGB
• Unsharp mask
  • Very slight adjustment here, just to add some detail to the crescent and surrounding nebulosity
• DarkStructureEnhance, default settings
• PixelMath to screen stars back in
• StarReduction script
  • Create a starless version first (or rather, take a clone before you added them back in)
  • Under Start Reduction Parameters, set mode to "Soft" and apply
• Rotate and crop for framing
• Save and export

 

[Spongey]

My attempt

Colour palette used was the following pixelmath expression, with the crescent itself a more classic hue-adjusted HOO.

// R:
((Ha^~Sii)*Sii + ~(Ha^~Sii)*Ha)*.6 + Ha*.4

// G:
(Oiii^~Sii)*Ha + ~(Oiii^~Ha)*Oiii

// B:
Oiii*.8 + Ha*.2

Workflow was relatively standard:

- DBE each channel

- Remove stars

- Stretch each channel individually with GHS and HT

- Combine channels using the above Pixelmath expression

- Iterative Curves, LHE, and a touch of MLT NR

- Into lightroom for hue and saturation adjustments

- Back into Pixinsight for final adjustments and star-recombination

   - To achieve somewhat normal coloured stars the following Pixelmath expression was used for the extracted stars from each channel. SCNR on both the output of the below and the inverted version was used to remove green and magenta respectively.

// R:
Ha_stars

// G:
Sii_stars

// B:
Oiii_stars

Cheers

Edited December 8, 2023 by Spongey

[Budgie1]

I have a couple of renditions so far (it's cloudy so I have plenty of time on my hands ).

First here is a Foraxx version.

Software in PixInsight and the workflow looks like this:

• Checked all three files for the need to crop & background extraction - none needed it so I didn't bother with these processes.
• LinearFit onto the Sii channel.
• Bin x2 so my old PC can cope with the file size (new motherboard bundle on the way )
• BlurXTerminator matching each channel to the correct PSF using Script>Render>PSFImage
• HistogramTransformation to stretch the images and then enhanced some areas using GHS
• StarXTerminator to remove the stars on each image.
• ForaxxPalletUtility to combine the background & star channels into the one image.
• Enhanced with Curves
• NoiseXTerminator set at 40% to take out any noise created by processing

[Budgie1]

My next rendition is an HOO version.

Again the software is PI and the I used the same methods in the linear phase, so the workflow is the same until after the stretch.

• Checked all three files for the need to crop & background extraction - none needed it so I didn't bother with these processes.
• LinearFit onto the Sii channel.
• Bin x2 so my old PC can cope with the file size (new motherboard bundle on the way )
• BlurXTerminator matching each channel to the correct PSF using Script>Render>PSFImage
• HistogramTransformation to stretch the images and then enhanced some areas using GHS
• StarXTerminator to remove the stars on each image.
• Using LRGBCombination, combine the images using R=Ha, G=Oiii & B=Oiii, nothing was using in the luminance channel.
• Use Curves to enhance the colours with saturation & RGB/K
• HDRMultiscaleTransformation using 9 layers
• Script > EnhanceDarkStructures with default settings
• NoiseXTerminator set to 50% to remove some processing created noise
• PixelMath to add the Ha stars only onto the background using ~((~HOO)*(~HaStar))

[carastro]

Processed entirely in Photoshop.

Each channel processed separately before combining

Combined in RGB channels,  some high pass sharpening. 

Using levels and Curves, star reduction, selective colour.

(Processed twice and the results were combined). 

 

 

 

 

Edited December 13, 2023 by carastro

[Graham Darke]

Here's my effort in Pixinsight. I only used the Ha and OIII channels assigned HOO. Then ran it through BlurX. GHS followed by StarX then applied Unsharp Mask to starless followed by NoiseX and Dark Structure Enhnace in Scripts. Starless was then treated with narrowband normalisation  preserving Ha and boosting the OIII very slightly. Colour mask mod was then applied and had a very small amount of red added to the yellow parts of the image. Stars image had some curves to tame the blue followed by SNCR on stars only. Pixelmath to recombine. 

[bottletopburly]

 Processed in Startools Matrix set to SHO 40SII+60Ha,70Ha+30OIII,100OIII

 

[ScotiaAstro]

Here's my rendition of this lovely piece of our night sky and thanks to Grant and the FLO team for providing some wonderful data to work with!

This was edited in Pixinsight entirely with the following workflow and hope you all like it:

Dynamic Crop all images to same dimensions

Ran GraXpert through Pixinsight Toolbox on all images

Ran BlurXterminator on all images

Ran NoiseXterminator on all images at 0.60 Denoise and 0.15 Detail

Ran a basic Histogram Stretch 

Ran LRGB Combination with HSHO settings to retain some of the Green because I like to see some in my image

Ran Correct Magenta Stars Utility 

Ran Clone for Starless Tool at Star Reduction Method 3 with StarXterminator

Removed Stars with StarXterminator

Slight Curves adjustment for contrast boost

Worked with various Colour Mask tools to bring out more details with curves

SCNR to take some green elements out

Another run of NoiseXterminator at 0.40 and 0.15 Detail

Ran Dark Structure Enhance Utility

Added Stars back to Image

Best of luck to all of the entries and clear skies to you all! 

Steve
 

[Budgie1]

This one I'll call "Experimentation with Fire", as that's what I think it turn out like. It was a bit of messing around and trying things until I thought they looked okay.

I think this is the workflow in Pixinsight:

• Run GraXpert on all three images (no cropping, ABE or DBE needed)
• LinearFit onto the Sii channel.
• Bin x2
• BlurXTerminator matching each channel to the correct PSF using Script>Render>PSFImage
• Manual HistogramTransformation to stretch the images and then enhanced using GHS
• StarXTerminator to remove the stars on each image.
• Using PixelMath I made two new images, a new Red Channel Ha*0.8+Sii*0.2 and a new Green/Blue Channel Oiii*0.8+Sii*0.2 - seemed like a good idea!
• Using LRGBCombination, combine the images using the new images to make HOO colour image, again using nothing in the luminance channel.
• Created a Red colour mask and played with that to bring out the "Fire" then created a Magenta colour mask for the blue areas, including the Crescent & Bubble.
• Use Curves to enhance the colours with saturation & RGB/K
• HDRMultiscaleTransformation using 9 layers
• Script > EnhanceDarkStructures with default settings
• NoiseXTerminator set to 60% to remove some processing created noise
• Use LRGBCombination to combine the stars into an HOS star image, applied star reduction with MorphologicalTransformation and reduced the saturation.
• PixelMath to add the stars onto the background using ~((~HOO)*(~Stars))
• Finally into PhotoShop CS3 for some Contrast & Brightness + some colour tweaks.

[Taman]

Thank you to Grant and Ikarus for sharing this data, it gave me something to do during this long spell of poor weather. Here's a ForaxX SHO version processed in Siril and Photoshop. I had some Deja Vu with this one, as it looks very similar to an image I took in October with the same framing!

I used Graxpert to remove a slight gradient from each image stack, followed by histogram stretching in Siril. Pixelmath was used for the basic SHO combination with a luminance layer to control contrast and give it an extra boost.

ForaxX SHO:

R = (Oiii^~Oiii)*Sii + ~(Oiii^~Oiii)*Ha
G = ((Oiii*Ha)^~(Oiii*Ha))*Ha + ~((Oiii*Ha)^~(Oiii*Ha))*Oiii
B = Oiii

Luminance = (Ha^2 + Oiii^2 + Sii^2)/(Ha + Oiii + Sii)

More information can be found at: https://thecoldestnights.com/2020/06/pixinsight-dynamic-narrowband-combinations-with-pixelmath/

The stars were removed with Starnet++, with further stretching, SCNR, colour saturation and contrast equalization. I also created a lightly stretched colour calibrated HOO version to use as a star mask.

All the layers were brought into Photoshop for final processing with levels, curves and colour adjustments. The stars had a few problems mainly on the right side of the image, which I managed to "repair" with the blend mode darken - nudge method. It's not scientifically accurate but looks nicer than it was! The high pass filter was used for sharpening, with further slight sharpening and noise removal in Topaz Denoise.

Good luck everyone and clear skies!

Tony.

[Phillyo]

Here's my attempt. I tried a couple of different colour schemes but quite like this one.

This is BlurX on all 3 channels, then combined in NBcolormapper script with a palette I made. Then StarX, a small amount of NoiseX, stretching done with GHS on the starless image then stars separately. I added a touch on saturation with curves then combined the stars and starless image back together again. A small reduction in stars using the StarReduction script in Pixinsight and that's about it really.

Absolutely beautiful data to work with! It didn't require a lot of work to be honest.

Phil

[cfinn]

Thank you for providing this wonderful data! As part of my workflow I used the very latest version of BlurXterminator with AI4, which does an absolutely unbelievable job of cleaning up the corner stars.

Completely processed in PixInsight. Steps were as follows, following a few iterative attempts backwards and forwards:

1. ChannelCombination - straight SHO palette, 1:1:1 ratio across the three channels.
2. BlurXterminator with sharpen stars at a setting of 0.5 (reduce FWHM by 50%) and sharpen non-stellar at a setting of 0.9.
3. ColorCalibration with a starless copy of the entire image (made using StarXterminator) as a white reference and a small dark area bottom left as a background reference.
4. BackgroundNeutralization using the same background reference as above.
5. Initial stretch using HistogramTransformation with settings transferred from the default ScreenTransferFunction.
6. Stars are removed (unscreened) at this point with StarXterminator.
7. Invert the star image, apply SCNR with default settings and invert back to remove the magenta halos. These stars are kept for screening back later and the following steps are applied to the starless image.
8. Create a binary mask using the GAME script to exclude the Crescent Nebula and apply to the image. It's already very bright at this point and this avoids saturating it in the next step.
9. A series of small stretches to the brighter parts of the image using GenaralisedHyperbolicStretch and carefully selected symmetry points to create a smoothly downward sloping histogram in log space. This creates smoother transitions in brightnesses across the mid-tones.
10. Remove the mask applied in step 8.
11. A final stretch with GenaralisedHyperbolicStretch to brighten fainter nebulosity and bring it to the fore.
12. Re-apply the mask from step 8 for the next two steps to protect fine detail in the Crescent.
13. An application of HDRMultiscaleTransform with 8 layers and a lightness mask to recover lost contrast and detail in the brighter nebulosity (particularly the top left).
14. MultiScaleLinearTransform to slightly enhance details at various scales of interest with greater contrast.
15. Remove the mask from step 8 again.
16. Screen the stars from step 7 back onto the image.
17. GeneralisedHyperbolicStretch in saturation mode using a mid-tones transfer function and a symmetry point slightly to the right. This boosts saturation in the nebulosity but not the background / faintest nebulosity.
18. Finally, NoiseXterminator with a de-noise setting of 0.7 to remove noise mostly introduced from processing steps, as the data was mostly noise free to begin with!

Hope you enjoy it. I find the range of colours and structures across the image completely mesmerising! The massive integration time really shows here.

Charles

Edited December 16, 2023 by cfinn

[WolfieGlos]

Here's another attempt, in SHO with a more traditional palette including the greens. ADMINS - if this isn't allowed, then please remove my original submission above.

The intention was to maintain the detail in the Ha but also bring out the detail in the OIII, so I applied an OIII luminance layer to the image and I think I managed to successfully bring it out in both the Crescent and Soap Bubble. With the release of the new tools in PI, I'm sure a lot of images will now feature perfect stars - being a non PI user, I have to make do with other, more manual methods.

Workflow as follows, using Siril, Topaz, Starnet and GIMP:

1.  Open Ha file in Siril, apply a Histogram stretch on Auto settings.
2.  Repeat for OIII and SII.
3.  Run Starnet on each of Ha, OIII and SII.
4.  RGB Compositing; assign starless images as a SHO palette using default colours. Save file as SHO.
5.  RGB Compositing; assign starless images as a SHO palette using default colours, with OIII as Lum on a CIE L*a*b composition. Save file as LSHO.
6.  Open both files in GIMP, overlay LSHO on screen mode 100%.
7.  Curve black point adjustment to LSHO.
8.  New Layer from Visible. Steep S-curve for contrast.
9.  Export to Topaz De Noise, Standard Mode; 75, 75, 74, 100.
10.  Open denoise image in Siril.
11.  Wavelets Transformation (2, 1.5, 1.3, 1.2, 1.2, 1.1)
12.  GHS ASINH pivot: 0.103, amount: 4.47 [0.00 0.37]
13.  GHS pivot: 0.563, amount: 0.57, local: 0.00 [0.00 0.79]
14.  Open in GIMP. Apply small s-curve tweak, and 1.07 sat boost. Save as STARLESS NOISE-REDUCED IMAGE.
15.  STAR PROCESSING
16.  Back in Siril, run RGB Compositing; assign the original SII, Ha and OIII images as a SHO palette using default colours. Save file as SHO_Starless.
17.  Negative Transformation
18.  SCNR (type=average neutral, amount=1.00, preserve=true)
19.  Negative Transformation
20.  GHS SAT pivot: 0.000, amount: 0.90, local: 0.00 [0.00 1.00]
21.  Run image through Starnet
22.  Open the new starless and stars images in GIMP. Use subtract mode to acquire stars Only image.
23.  Create "New from Visible".
24.  Copy layer into STARLESS NOISE-REDUCED IMAGE. Set at bottom of stack, blend mode of Normal.
25.  Set STARLESS NOISE-REDUCED IMAGE to Lighten only (thanks for this new method ollypenrice - it worked well!).
26.  For the star layer, apply curve enhancement to show more stars. Apply some sharpening using GIMP defaults.
27.  Duplicate stars-only image, and using GIMP Astronomy Plugin (Georg Hennig: http://www.hennigbuam.de/georg/gimp.html ), use filter for Round Stars to change angles in left corner. Black mask, and brush in.
28.  Repeat for the other 3 corners.

Once again, thank you for providing this amazing data for us to work with, especially during a time of endless cloud cover.

Edited December 17, 2023 by WolfieGlos

[step_hen]

Here is my effort. First time processing SHO data and I think I like it. Might need to invest in a mono setup in future!

Processed in Pixinsight as follows

• Graxpert on all three images
• Linear Fit to Si
• BlurX and NoiseX to all three images
• Combine with ForaxxPaletteUtility (I tried various combinations of HOO, SHO with and without luminance layers and preferred the Foraxx outcome)
• Remove stars with StarX and stretch stars only image with histogram transformation
• GHS on starless image
• Colour masks to increase the saturation using curves
• Contrast enhancement using Curves
• some local histogram equalisation to enhance the details
• DarkStructureEnhance script
• Rescreen Stars
• Slight star reduction

Thanks for providing the data!

Stephen

 

[WolfieGlos]

Thought I'd take another stab at this one, what with the dreadful weather we're all experiencing, and I decided to go with a different colour palette.

Red doesn't appear to be popular, so I decided to go for a palette using it and trying to fulfill the brief of getting the most of out all of the data provided. So this is still an SHO mix, however each are assigned to their "true colours" as defined in Siril's RGB Compositing tool. I also decided to go for less contrast to let the Ha in the darker areas be part of the show while letting the stars - although reduced - try to shine through too.

Processing details as below, mostly edited in Siril (including noise reduction) and final polishing and combination in GIMP.

SIRIL: RGB Compositing: SHO, assigned to "true colours" (671.7nm, 656.28nm, 500.7nm) with Ha for luminance, HSV composition.
Run Starnet and open Starless image:
Asinh Transformation: (stretch=1000.0, bp=0.00000)
Histogram Transf. (mid=0.113, lo=0.011, hi=1.000)
Wavelets Transformation (4, 2, 1.5, 1.2, 1.2, 1.1) 
GHS LINEAR BP: 0.03
GHS pivot: 0.272, amount: 0.77, local: 0.78 [0.00 0.68]
NL-Bayes denoise (mod=1.000, CC enabled)
OPEN IN GIMP, s-curve to red channel. Colour temperature tweak.
Open Stars-only image in Siril:
Negative Transformation
SCNR (type=average neutral, amount=1.00, preserve=true)
Negative Transformation
GHS SAT pivot: 0.000, amount: 0.90, local: 0.00 [0.00 1.00]
Export Stars to GIMP, overlay onto starless Screen Mode 100%.
Curves to stars to reduce. Sharpening to stars using GIMP defaults.
Duplicate stars-only image, and using GIMP Astronomy Plugin (Georg Hennig: http://www.hennigbuam.de/georg/gimp.html ), use filter for Round Stars to change angles in left corner. Black mask, and brush in.
Repeat for the other 3 corners.

Once again, thank you for providing the data and good luck to the judges in choosing the winners from the superb entries to date.

[Budgie1]

Here's another rendition from me, this time a slightly different pallet used again.

The basic processing in the linear phase is the as my others above (which I'll add to the workflow anyway for completeness ). The pallet I used looks like this and was the input to PixelMath:

// R: sii*0.4 + ha*0.6
// G: ha*0.3+oiii*0.7
// B: oiii

• Run GraXpert on all three images (no cropping, ABE or DBE needed)
• LinearFit onto the Sii channel.
• Didn't have to Bin x2 on this one because I have a new motherboard & AMD Ryzen 7 7700X processor, which has speeded things up a bit.
• BlurXTerminator matching each channel to the correct PSF using Script>Render>PSFImage
• Manual HistogramTransformation to stretch the images and then enhanced using GHS
• StarXTerminator to remove the stars on each image.
• Combine the images using the formula above and create a new layer by extracting the luminance layer from the combined image.
• Sharpen the new Lum layer using UnsharpenMask and then add that to the combined image using LRGBCombination to sharpen the whole image a little.
• Use Curves to enhance the colours with saturation & RGB/K
• HDRMultiscaleTransformation using 9 layers
• Script > EnhanceDarkStructures with default settings
• NoiseXTerminator set to 50% to remove some processing created noise
• Used the Foraxx stars from the previous version, with some star reduction and colour adjustments in Curves, then used PixelMath to add the stars onto the background.

Using this method I found there was a lot more fainter dust detail that I was able to bring out than I did before and give it a little bit of contrasting colours as well.

[Rob63]

A huge thank you to FLO & IKO for this, it's such a treat to work with such fantastic data.
Perfect timing too as I have been thinking of pulling the trigger on the StellaMira 90mm triplet so this was a fantastic insight into just how good this scope is !

I wanted this image to show the magnificent background nebulosity while still looking natural and not over-saturated.

Pixinsight load Ha, OIII, SII and do a slight Crop and DBE to each

Ha, OIII, SII => stacked as Master Lum

Deconvolution with BlurXTerminator (pre V2 🙂 )
Slight noise reduction on OIII & SII channels via MultiscaleMedianTransform  (MMT)
Basic Histogram Transformation & Masked stretch

Channels combined with PixelMath

• Red: Sii*0.35+Ha*0.65
• Green: Ha*0.35+Oiii*0.65
• Blue: Oiii

StarXTerminator to remove stars and process separately.
Multiple rounds of Histogram Transformation
SCNR
LRGB combined with masterLum

Stars
RGB mapped as SII Ha OIII
Photometric colour calibration for background neutralisation (narrowband mode)
Several gentle applications of Histogram Transformation as I want to de-emphasise the stars a bit.
Curves (saturation)

Export to photoshop
Adjust colour, saturation & contrast to taste.
Add stars layer (linear dodge(add) )
Add any final tweaks
 

[Laurin Dave]

Here's mine....

 

Processed  in Pixinsight and Photoshop...    

1. Ha, Sii and Oiii given STF stretch, Ha then given light dose of LHE 

2. Combined using Pixinsight Foraxx palette

3. Stars removed using SXT from Foraxx and stretched Ha

4. Selective stretching,  Local Histogram enhancement  and Saturation GHS and LHE 

5. Selective application of Ha and Oiii as luminance

6. Noise reduction using NXT

7.  Ha Stars applied as luminance to the Foraxx stars

8.  Stars blurred, shrunk and sharpened in Photoshop and applied as Screen layer

9. Curves and levels in Photoshop to finish

 

Dave

 

 

 

 

 

 

 

[gorann]

Thanks a lot Grant and Ikarus!

Excellent data as always and a lot of great renditions have been posted!

Here is my first version.

Started off by combining the filters as a HSO image.

Run the new BlurXT2 AI4 on it.

After some stretching in PS there was a lot of green areas (so apparently there is a lot of Sii in this area).

Since I am no fan of green in astrophotos I stared tweaking the colours using selective color and curves in PS, all on a starless layer (StarXT).

Then a bit of NXT and HiPass filtering.

I am sure I did a few other things that I forgot about.

 

There are some interesting filamentous structures, for example up in the top left corner, and some blue structures to the left of the Bubble. Makes me think SNRs. Maybe someone here knows.

 

Cheers, Göran

Edited December 28, 2023 by gorann

[wimvb]

My first iteration. A custom blend in PixelMath, processed in PixInsight. I think the image is still a bit too flat, so I'llprobably update this post before year's end.

The process so far:

Red: 75% Ha, 25% S

Green: 10% Ha, 90% O

Blue: 100% O

BlurXterminator, StarXterminator

Starless image:

Histogram Transformation

Curves Transformation

Multiscale Median Transform with masks to target specific areas with bias to increase local contrast

NoiseXTerminator

Star image.

histogram transformation

PixelMath to put the stars back into the  image

 

[Richard_]

NGC 6888 in colour mapped SHO Palette

Processed entirely in PixInsight using various addons. This submission utilises the full S, H and O data which were colour mapped according to their natural hues. This was achieved by using the "NBColourMap" script created by Mike Cranfield and Adam Block which allows you to assign a hue to each monochrome data source and choose the blend strength for creating a combined RGB image. This gives you the best of both worlds by having some lovely quality narrowband data represented in a more natural RGB manner.

Whilst the end result may look like a similar colour palette to my previous attempt, this attempt was created using the additional Sulphur data rather than just HOO, and a different enough workflow that I consider this to be a separate submission. Mods, if you disagree, then please disregard my first submission on 07-Dec-2023 and replace with this one

See the picture below followed by a brief overview of the workflow I used. All addons are listed below and I have provided the source for others to access them, some are paid (£) and some are free.

Workflow

Software: (£) PixInsight 1.8.9-2 Ripley

Add-ons: (£) BlurXterminator, (£) NoiseXterminator, (£) StarXterminator, (Free) NB Colour Mapper, (Free) Star Reduction

Workflow

• Star align S, H and O master lights
• Run NBColourMapper script to assign S, H and O data to specific hues, choose blend strength and create RGB image
• BXT AI4 to correct stars
• Create clone of image to generate RGB stars
  • On clone, run SPCC, BXT AI4, Histogram Transformation and remove stars with SXT (unscreen)
  • Discard "RGB starless" but keep "RGB stars" to one side, and continue with original image "NB"
• BXT AI4 for deconvolution
• SXT to remove stars
  • Discard "NB stars" and keep "NB starless"
  • Continue working on "NB starless"
• Histogram transformation
• NXT
• Curves Transformation
  • S-curve on RGB
  • Saturation boost
• HDR Multiscale Transformation (with mask applied to correct the bright highlights)
• Unsharp mask (with convoluted luminance mask applied to prevent sharpening background)
• Using PixelMath, Screen "RGB stars" into "NB starless" image
• Run Star Reduction script
• Crop out edge artifacts
• Save and export

[happy-kat]

Lovely and clean thank you for sharing, edited posting to have full size process. StarTools compose weighting by capture length for luminance and ha also added for NB enhancements | crop just 10 pixels all round | bin 50%| AutoDev | Wipe |AutoDev | used Repair on the stars for the elongation | Sharp | Flux | Noise plus created several masks along the way

Love the detail of this area and the very very long list of interesting facts on it and I like the mono cleanness, the ha file was super strong

 

Edited December 29, 2023 by happy-kat

[wimvb]

A different channel combination, so a different entry. (Judges, if this violates the rules, then please disregard my first entry.)

This time:

(Edited)

Red = 50/50 Ha/Sii

Green = 80/20 Oiii/Ha

Blue = 80/20 Oiii/Ha

Removed Hydrogen from the green and blue channels, and reduced the amount of Oxygen in the green channel. (Which should make this a SHoO image.)

 

Process (PixInsight)

• DBE to lift the lower left corner
• BlurXTerminator
• StarXTerminator

Starless image:

• Background Neutralisation, using a very small preview of one of the dark nebulae as a reference
• Histogram Transformation using the screen transfer function as a permanent stretch. This is something which I otherwise NEVER do. This time it worked.
• Various curves transformations to adjust contrast in dark regions and middle regions
• HDRMT, protecting the Crescent nebula with a mask
• Multiscale Median Transform on the Crescent and on smaller details in the Ha clouds.
• Colour saturation
• Noise reduction (NoiseXTerminator)
• Aligning the three colour channels with histogram transformation and curves transformation; adjusting the black points and small individual stretches to get a more pleasing colour balance and to enhance the faint blue clouds in front of the hydrogen clouds.

Stars:

• Histogram transformation in several passes in order to control the star size

Combining the starless and the stars images with PixelMath: ~(~starless*~stars)

Small colour and contrast adjustments, mainly with LHE at 128, 64 and 32 kernel radius at very low strength

Edited December 30, 2023 by wimvb
process tweaks and description update