Cygnus widefield processing request - Forums

Curious to see how others process this data. I want to see if I can get more vibrance from the blue wolf rayet star.
fits link
https://www.mediafire.com/file/n2d76o7qzzliyqn/Cygnus_135mm_Widefield_Asi533.fits/file
Tiff link for reduced file size
https://www.mediafire.com/file/zxzw75kp2ogyuoq/Cygnus135mmAsi533.tif/file

Poor focus and tilt. You may want to be careful there.

Hi there,

I had a quick stab at your data. While Andrea is right and there is some slight tilt/misfocus in your image, it's definitely salvageable (though I agree to sort that out in the future).

All in all the data is decent, there just isn't enough of it to really bring out the details in this area. I don't know the gear/exposure infos, but I assume its not more than a couple of hours. Going deep is always worth it!

Ultimately the image came out quite soft, because of the heavy noise reduction applied. This is highly subjective, but I for my part prefer more depth at the sacrifice of some perceived detail.

As for the processing, this is what I did:

Linear (PixInsight)

Rotate
Crop
BlurXT
DBE
SCNR
StarXT
Noise XT
Histogram Transformation -> Export Luminance, RGB, Stars image

NonLinear (Photoshop)

Recombine Stars + RGB
Adjust Colors (ChannelMixer/ColorBalance)
Boost Blues
Noise Reduction
Star Reduction
Recombine LRGB
Final Color Adjustment
Saturation Adjustment

I hope this helps you

CS Julian

Edit: Just realized that I had night mode turned on on my laptop, so the colors are way too cold!

Hi tantalusthief,

Julian has already given you a really clear step-by-step workflow—thanks, Julian! While I was waiting for my own data to finish, curiosity got the better of me and I tried a very quick pass on your file too. I’ll be honest: I lost interest part-way through. Under normal circumstances I wouldn’t spend much time on such a shallow data set, but it was fun to experiment.

My main takeaway is that the passion is definitely there—keep that flame burning! The single biggest improvement you can make is to go deeper: plan for longer total integration time, and if you can’t capture it all in one outing, add more sub-frames over several nights. Astrophotography is all about pulling every last bit of usable signal out of the sky and showing it off; with so little data, no amount of processing wizardry will give you a truly “great” result.

I’ve attached my quick-and-dirty version below (certainly not the best possible). Hope it helps set a reference point as you keep experimenting.

Clear skies and good luck!

— Alpha Zhang

Alpha Zhang:
Hi tantalusthief,

Thank you for the tips. I'm somewhat impatient and I don't have an eq Mount. But yeah I'll try to go deeper for my next targets.

andrea tasselli:
Poor focus and tilt. You may want to be careful there.

Focusing on the lens is kinda tricky.

Julian Shroff:
Hi there,

I had a quick stab at your data. While Andrea is right and there is some slight tilt/misfocus in your image, it's definitely salvageable (though I agree to sort that out in the future).

All in all the data is decent, there just isn't enough of it to really bring out the details in this area. I don't know the gear/exposure infos, but I assume its not more than a couple of hours. Going deep is always worth it!

Ultimately the image came out quite soft, because of the heavy noise reduction applied. This is highly subjective, but I for my part prefer more depth at the sacrifice of some perceived detail.

As for the processing, this is what I did:
Linear (PixInsight)
Rotate
Crop
BlurXT
DBE
SCNR
StarXT
Noise XT
Histogram Transformation -> Export Luminance, RGB, Stars image

NonLinear (Photoshop)
Recombine Stars + RGB
Adjust Colors (ChannelMixer/ColorBalance)
Boost Blues
Noise Reduction
Star Reduction
Recombine LRGB
Final Color Adjustment
Saturation Adjustment

I hope this helps you

CS Julian

Excellent. I like how bright you made the wolf rayet nebula.

Supposing that you used a dual band filter (Ha&OIII) with your color camera:

HOO processing (PixInsight):

1. Extract Ha and OIII
2. DBE per channel
3. Recombine in HOO
4. Astrometry => Image Solver
5. SPCC
6. BlurXT
7. StarXT => starless & stars

8. Starless:
8.1. NoiseXT
8.2. Generalized Hyperbolic Stretch
8.3 Curves Transformation
8.4 Narrowband Normalization
8.5 Selective Color Correction

9. Stars:
9.1 ArchsinhStretch
9.2 Generalized Hyperbolic Strecth

10. Recombine starless & stars

RGB processing (PixInsight):

1. DBE
2. Astrometry => Image Solver
3. SPCC
4. BlurXT
5. StarXT => starless & stars

6. Starless:
6.1. NoiseXT
6.2. Generalized Hyperbolic Stretch
6.3 Curves Transformation
6.4 Narrowband Normalization (ussually I do not apply it for RGB processing, but in this case I used it to boost the blue)
6.5 Selective Color Correction

7. Stars:
79.1 ArchsinhStretch
7.2 Generalized Hyperbolic Strecth

8. Recombine starless & stars

Just curious to know:
- how much integration time?
- dual band filter?
- dither & drizzle (how much)?

I hope it helps.
Clear Skies!

I recently shot a subset of this widefield, also with the goal to try and get the blue shell from WR 134 to come out nicely. It wasn't until I approached ~12 hours total of dual-narrrowband subs did I feel like I was extracting enough signal in that particular area in order to have something decent to work with in post-processing. More would have been even better.

Thanks SkyHoinar Those pictures are super great, Loving the rich details in the hydrogen you brought out. What is the Selective Color Correction?
Regarding your questions
Integration time is 193 x 20 seconds which is an 1 hour 4 minutes.
Duo band filter is SV220
I don't think I used dither or drizzle.

Thanks SkyHoinar Those pictures are super great, Loving the rich details in the hydrogen you brought out. What is the Selective Color Correction?
Regarding your questions
Integration time is 193 x 20 seconds which is an 1 hour 4 minutes.
Duo band filter is SV220
I don't think I used dither or drizzle.

Selective Color Correction is a tool for color adjustment and it is part of a toolbox for PixInsight that you can find here: https://www.ideviceapps.de/pixinsight-toolbox.html
Once installed (instructions on the website) you will find it under Script => Toolbox

Thank you for sharing the capture details!
Very short exposures, only 20 sec. and though the information is there. I am sure with more integration time you will get more details (and more blue :-).

I was actually preparing to shoot this target myself too as my next project.
I took a couple of subs (7x300 sec.; 35 minutes in total) few nights ago at the end of a session on the Cygnus Loop, just to prepare the framing.
After a quick processing, this is what I've got. It looks promissing.

Clear Skies!

Thanks SkyHoinar Those pictures are super great, Loving the rich details in the hydrogen you brought out. What is the Selective Color Correction?
Regarding your questions
Integration time is 193 x 20 seconds which is an 1 hour 4 minutes.
Duo band filter is SV220
I don't think I used dither or drizzle.

Selective Color Correction is a tool for color adjustment and it is part of a toolbox for PixInsight that you can find here: https://www.ideviceapps.de/pixinsight-toolbox.html
Once installed (instructions on the website) you will find it under Script => Toolbox

Thank you for sharing the capture details!
Very short exposures, only 20 sec. and though the information is there. I am sure with more integration time you will get more details (and more blue :-).

I was actually preparing to shoot this target myself too as my next project.
I took a couple of subs (7x300 sec.; 35 minutes in total) few nights ago at the end of a session on the Cygnus Loop, just to prepare the framing.
After a quick processing, this is what I've got. It looks promissing.

Clear Skies!

Was the selective color tool what you used to bring out more of the red hydrogen? Compared to my processing that's the biggest difference I see. How did you use narrowband normalization to bring out the blue?

Was the selective color tool what you used to bring out more of the red hydrogen? Compared to my processing that's the biggest difference I see. How did you use narrowband normalization to bring out the blue?

For the red, it came out after stretching.

For the blue:

First, I used Narrowband Normalization to bring out some of the blue (even in the RGB image, yeah I cheated a bit :-)

In Narrowband Normalization I used:

Palette: HOO
Blend Mode: Mode 2 (to get those red-blue colors)
And I chose to preserve Luminance, but you can try other options if they give better results for you

Then in Selective Color Correction, I boosted up the blue:

first on the Red channel (select it from the Mask dropdown):

I slightly increased the Red component and diminished the Blue to get a bit colder hue in the Red (which is most of the image)
Then I slightly increased the saturation and luminance (if the Red is lighter then the blue will be more visible)

then on the Blue channel:

I slightly increased the Blue component
Then I increased the saturation quite strongly and I played with the luminance and contrast

then on the Highlights I again increased the Blue and its saturation and I played with the luminance and contrast

Otherwise, just play arround with these elements to see what you get.

Anyway as there is no much signal, you are quite limited in how much of the blue you can bring out.

Let me know how it goes.

I found two Wolf Rayet stars in my lastest wide field recording around NGC6888, crescent Nebula. Details are here: https://app.astrobin.com/i/z16y6z

There is no catalog of WR stars and many are too small I think, but NGC6888 and WR134 are easily recognizable in this image.

For each tile in my 3×3 mosaic I do the weighted batch preprocessing, I create the mosaic with GradientMergeMosaic, and in the end you do an astrometric solution of the entire mosaic which is more than 1 Gb. But PixInsight did not crash, my compliments for its stability.

What works best is a HOO combination in PixelMatch, you do the SpectralPhotometricColorCalibration, the SpectralPhotometricFluxCalibration both for narrow band images, and next a MultiScaleGradientCorrection withe the XMARS data, there is now a DR2 version. Sii does not really help, it did not work with MSGC.

Finally you stretch the image with MultiScaleAdaptiveStretch, finally you run BlurXterminator.

This is pretty much it, the challenge is to work with xifs files that are larger than 1 Gb.

When you zoom in to WR134 in https://app.astrobin.com/i/z16y6z you clearly see the oxygen arc, and some oxygen filaments. With NGC6888 it is a lot easier.