Astrophotography Processing Challenge April 2025

[AstroBee]

CALL FOR DATA!
We are in need of processing challenge data. Please consider submitting data for this fun challenge.
If you have data that you are interested in sharing, please reach out to me via PM so we can discuss it.

This month's data comes from Steve, aka @starfield and here's what he had to say about this data.

IC348 and the beautiful surrounding area in Perseus. This data set presents some real challenges: a bright star (Atik), a nasty lens flare, a busy starfield, and lots of dust.

This was shot over two nights (10/3 and 10/29) in October from my club site out in the Anza Borrego desert (Bortle 3). I kept the exposure short knowing that Atik was in the frame. I still don’t know that I’ve nailed this one as there are lots of tradeoffs but you should have a good time with this.

For the project, my camera was a ZWO 2600mm (pixels size 3.76) and I used a Chroma LRGB filter set. My scope is an Esprit 100 and has a focal length of 550mm. I ended up with a little under 9 hours of exposures and all the channels were shot at 120 seconds at 100 gain.

A little about the target:
VdB 19 is a beautiful reflection nebula in the Perseus molecular cloud with an associated star cluster IC 348. It features a large dusty red area to the right is LBN 749 contains both red emission and reflection nebula. Inside this area is Barnard 3 and other dark nebula. There are some nice little galaxies in the upper right part of the image frame as well as several Herbig Harro objects sitting under vdB 19 in this active star forming region.
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Remember, the XISF, FITS and TIFF zip files contain the identical data so there is no need to download all of them, just the format you prefer to edit. Please do not try to unzip the files on the Google Drive. Download the zip file you want to use and unzip it on your local drive.
https://drive.google.com/drive/folders/ ... drive_link

As always, have fun! It's a challenge, not a contest, so everyone is a winner!

[starfield]

So I just went back and reprocessed this. I'm not sure I made it any different, but did include the full frame, lens flare and all.



If you click thru the thumbnail you can see my attempts.

[Raselgethi02]

Nice clean data. No noise reduction needed but I struggled with getting the colours brighter.

Masked Stretch
S Curve on each
LRGB Combine
Starnet 2
Dimmed the stars and increased their saturation
Brightened the starless image and increased the saturation. Played with the RGB curves.
Pixelmath
Final curves to finish.

What is the secret for drawing out the colour?

[carastro]

Just downloading mine.

If you click thru the thumbnail you can see my attempts.

TBH I think I like Version J the best.

Carole

[carastro]

Not my best bit of processing. In particular could not control that big yellow star.
Processed in Photoshop, using various levels and Curves, SX, Equalizer function, and Selective colour.

It was however a treat to process something I have not yet done and given my LP I am unlikely to do, so thanks for that.

[Raselgethi02]

That is nice Carole.

How did you manage to get the reds to show so well?

Perhaps I will have another go.

[carastro]

How did you manage to get the reds to show so well?

Well l did a bit of Equaliser Function which brings out faint detail and then fiddled with selective colour increasing reds and blues. Think l overdid the blues.

Carole

[starfield]

Not my best bit of processing. In particular could not control that big yellow star.
Processed in Photoshop, using various levels and Curves, SX, Equalizer function, and Selective colour.

It was however a treat to process something I have not yet done and given my LP I am unlikely to do, so thanks for that.

Nice, Carole. Glad you enjoyed the data. I'm lucky to have dark skies available. 1.5 hours gets me out to my club site out in the Anza Borrego Desert and away from the bright lights of San Diego.

[starfield]

Nice clean data. No noise reduction needed but I struggled with getting the colours brighter.

Masked Stretch
S Curve on each
LRGB Combine
Starnet 2
Dimmed the stars and increased their saturation
Brightened the starless image and increased the saturation. Played with the RGB curves.
Pixelmath
Final curves to finish.


IC348.jpg


What is the secret for drawing out the colour?

Hmm.. I've played with ArcSin stretch to boost colors on one of my versions. Let me go check the history.

[starfield]

Nice clean data. No noise reduction needed but I struggled with getting the colours brighter.

Masked Stretch
S Curve on each
LRGB Combine
Starnet 2
Dimmed the stars and increased their saturation
Brightened the starless image and increased the saturation. Played with the RGB curves.
Pixelmath
Final curves to finish.


IC348.jpg


What is the secret for drawing out the colour?

Hmm.. I've played with ArcSin stretch to boost colors on one of my versions. Let me go check the history.

Ok. I checked the history on my RGB master based on my latest version posted above. It looked like this:

BlurXT (Correct Only)
Spectorgraphic Flux Calibration
MultiScale Gradient Correction
SPCC (Created small region of interest on the right side where there is less dust)
Make Copy for Stars processing
BlurX
StarX
NoiseX
GHS stretches
Final NoiseX

Then combined with my SuperLum master. SuperLum followed same basic flow except I did some HDRMT for some sharpening. Combined using ImageBlend script. Added stars back using Mike Cranfield's Screen Stars script.

[Raselgethi02]

Thanks Starfield.

I did the trial on Blur X and Noise X but they expired. So I bought Noise X But I can't afford Blur X as well till next month. And I didn't use Noise X because the data seemed very clean. In fact I didn't do much at all to the linear data except stretch it. Also I don't understand doing SPCC at the linear stage since the images are monochrome before they get combined. Seems I need to read up on SPCC. Think I will have another go.

[starfield]

Ah... left out that step on the list. Combined Red, Green and Blue with Channel Combination to create RGB master as the very first step.

[Jockinireland]

Hi Folks,

here is my take on this, nothing unusual in my processing

Combined the RGB
BXT
SPCC
DBE
Histogram stretch
NXT
SXT
Various stretches using colour masks, curves HT etc
Stretched the Stars a bit more and boosted colour in curves.

On the LUM
BXT
DBE
NXT
SXT
GHS
MLT to sharpen
pulled contrast with Unsharpmask
LRGBcombine

Some final curves tweaks then replaced the RGB stars. Giving this

[starfield]

I like what you did with the contrast here and the glow behind the dark nebula Barnard 4. Did you do that all with curves?

[Jockinireland]

I like what you did with the contrast here and the glow behind the dark nebula Barnard 4. Did you do that all with curves?

Yes, all done with judicious masking and curves really. Mostly on the lum.