IKO - NGC6888 Crescent Nebula SHO - Processing Competition

[AMcD]

This data was a joy to work on, compared to what I am able to extract from my Bortle 5 location. The entry was processed entirely in PixInsight, using the narrowband colour mapping script to combine the Ha, OIII and SII channels.

I used the following workflow to produce the image:

PIXINSIGHT

Linear:

- Star Alignment of Ha, OIII and SII channels;
- Dynamic Crop to remove any stacking artefacts;
- Dynamic Background Extraction for each channel;
- Calculate PSF for each channel;
- Apply BlurXterminator to each channel using calculated PSFs;
- Combine channels by assigning colour values at full saturation to each channel (Ha: 353; SII: 25; OIII: 195) and applying Background Neutralisation in NBColourMapper;
- Apply StarXterminator to combined image to produce starless image and stars image;
- Apply NoiseXterminator to starless image;
- Stretch starless image and stars image using Generalised Hyperbolic Stretch;

Non-Linear:

- Adjust contrast with Curves;
- Adjust Colour Saturation;
- Local Histogram Equalisation to bring out large and small structures;
- Bring out further detail and highlights using range, luminance and colour masks;
- Add back stars using PixelMath;
- Apply star reduction script;
- Adjust black point using Histogram Transformation.

😃

[gorann]

I take the opportunity of posting a new version where I started off by putting Ha and Sii (50:50) to the red channel and Oiii to both the blue and green channels (first time for me using Pixel math in PI - thanks @wimvb for guiding me). Then quite a bit of tweaks to the colour curves in PS.

I am still intrigued by some of the structures that emerges in this deep data in addition to the well known Crescent and Soap bubble.

Edited December 30, 2023 by gorann

[tomato]

I'm afraid I have had a senior moment with this one. I saw this thread but because there hasn't been an IKI competition for quite some time, I assumed it was the historic NGC6888 competition thread. 

So I've just sneaked this one in, although the days of spending 6+ hrs processing an image are a thing of the past for me.

APP SHO Hubble 4 channel combination, no LP removal applied.

BXT AI ver. 4 then SXT in PI. Histogram transformation, Curves transformation then adjustments in AP mainly with HSL and selective colour tools.

Star only image stretched with Histogram transformation, and saturation in Curves transformation in PI.

Recombined with Pixel Math, NXT applied at 35%.

If this dataset  doesn't make me trial FLO remote imaging, then nothing will.

[brunobou]

SHO treatment with deliberate inconsistency... Look for the error. and HOO
Workflow :
-In Pixinsight: really simple with the Xterminator suite
Blur and Noise Xterminator to reduce stars and noise.
Stretch images with "HistogramTransformation".
StarXterminator to separate background from stars.
Histogram equalization and tension.
PixelMaths to create SHO and HOO color images.
PixelMaths to create star color images.
-In Photoshop :
Creation of the 2 SHO + HOO images
Integration of nebulae and stars, and various image correction techniques: selective correction, hue/saturation, levels, curves etc.
Then mix of the 2 for the final SHO version

 

[TerryMcK]

Here's mine processed entirely with PixInsight.

Ran GraXpert on all three raw images but found it wasn't needed. You have good skies at the observatory.

Repaired the stars in the top right and other extremities using BlurXTerminator with AI4 - not sure what is going on there but might be a spacing issue?

Then the rest was done with normal PI processes. I processed the data as SHO.

I did run SPCC on the stars extraction pic before recombining with a starless pic to get a reasonable "normal" coloured stars in the image. Although what is normal in a narrowband image is one for debate 😊

[Xiga]

It must be a full year now since i last captured or processed anything, but I've been trying to get back in the Astro saddle lately. Of course, the awful weather we've been having here in N. Ireland certainly hasn't helped, but when i saw this i thought it would be a good opportunity to get back to processing again. 

Workflow for this was actually fairly simple. I don't have P.I, but the stars really needed BXT so i used trials for both P.I and BXT to correct them. APP was used for gradient reduction (which i did find was needed) as well as doing the initial stretching, before manually combining as SHO in Photoshop. Lots more stretching then done in PS. Star-Xterminator and Noise-Xterminator both used along the way (in PS, not P.I, just because i prefer to do as much as i can in PS) and finally a bit of high pass filtering. Also left some green in too, as i personally prefer it on SHO images. 

Decided to really push it, given the size of the data set. 

Thanks for sharing! 

Edited January 1 by Xiga

[Grant]

Thank you all for the entries - we will be judging this over the next week and will announce asap.

We have some other data sets we will be releasing soon as well 🙂