Heart of the Heart with Melotte 15

[wimvb]

Still no astro darkness for another two to three weeks. So, apart from tinkering in my observatory and things to do around the house, I'm reprocessing old data with new tools in the PI toolkit.

This is data that I collected back in 2021, Melotte 15. The Xterminator suite of processes allowed me to create a version that is closer to what I had intended when I captured the data. BlurXterminator for sharpening, StarXterminator to allow stars and nebula to receive their own processes, and NoiseXterminator to clean up.

I even tried GHS stretch but found a much simpler solution to stretch the nebula. After star removal, I simply used Histogram Transformation ("levels" in PS) to bring in the white point and black point for each channel separately (avoiding clipping). After that, some local contrast enhancement and colour saturation boost. Then brought the stars back in (stretched with masked stretch).

I goofed around with the data some more and found a simple way to fake a Hubble SHO palette. If you have a standard HaRGB image, you simply invert it, apply SCNR green, and invert it back. Voila!

The result was a little too "mustard" for my taste, so I blended 50-50 with a version in which I used PixelMath to mix the channels of the original image.

Red: $T[0]

Green: 0.8*$T[0] + 0.1*$T[1] + 0.1*$T[2]

Blue: (2*$T[2] + $T[1])/3

Personally, I like the natural look of the HaRGB image better.

Btw, that blue patch int middle of the image is not an artefact. It shows in Aladin's SDSS plates. But I couldn't find a reference or ID for it.

Edited August 2, 2023 by wimvb

[ollypenrice]

That's the best natural colour rendition I've ever seen...

Olly

[wimvb]

22 minutes ago, ollypenrice said:

That's the best natural colour rendition I've ever seen...

Olly

Thanks Olly. Much appreciated.

[peter shah]

I love that natural rendition 

[windjammer]

I'll go for the reduced mustard!

[wimvb]

1 hour ago, peter shah said:

I love that natural rendition 

Thank you, Peter. I like the natural look better too. Someone on a Facebook group suggested that I do this target in narrowband and create an image in SHO. I don't even have any nb filters other than Ha. So I played with the data and stumbled upon a simple method to completely change the colour scheme of an image. I posted it here just for fun. The natural look with the blue haze is the one that I was aiming for.

[wimvb]

5 minutes ago, windjammer said:

I'll go for the reduced mustard!

I'm glad you like it. This area of the Heart nebula can look fabulous in a proper Hubble palette image with a 3D look to it, but here I was aiming for a natural look. The "mustard version" was more of a coincidence. A nice one though. The Hubble palette is meant to show the abundances of Hydrogen, Oxygen, and metal (Sulphur). But this colour scheme is as far from reality as you can get. Hydrogen under low pressure has a red/magenta glow, while under high pressure, it glows in pink.

[Sunshine]

It’s a beautiful image!

[Rodd]

Rgb palettes rule.  I love them.  Unrequited love, I’m afraid (a couple of  dalliances, but overall I am a male spinster).  Interesting the you have succeeded in faking a Hubble palette from HaRGB.  The other way I am familiar with (mostly with bicolor).  Your HaRGB is sweet. I have incorporated the 3 RC tools into my work flow in a semi- religious fashion. I find them incredible.  Your acquisition skills and processing expertise came together for this one
 

 

[wimvb]

7 hours ago, Sunshine said:

It’s a beautiful image!

Thank you, Sunshine.

[wimvb]

6 hours ago, Rodd said:

Rgb palettes rule.  I love them.  Unrequited love, I’m afraid (a couple of  dalliances, but overall I am a male spinster).  Interesting the you have succeeded in faking a Hubble palette from HaRGB.  The other way I am familiar with (mostly with bicolor).  Your HaRGB is sweet. I have incorporated the 3 RC tools into my work flow in a semi- religious fashion. I find them incredible.  Your acquisition skills and processing expertise came together for this one
 

 

Thank you for your kind words, Rodd. 

[alan potts]

Superb as usual and Olly saying that tells us all something.

Alan

[Lee_P]

There are corkers, good job!

[simmo39]

V nice! Getting me in the mood for darkness!

[windjammer]

14 hours ago, wimvb said:

Still no astro darkness for another two to three weeks. So, apart from tinkering in my observatory and things to do around the house, I'm reprocessing old data with new tools in the PI toolkit.

This is data that I collected back in 2021, Melotte 15. The Xterminator suite of processes allowed me to create a version that is closer to what I had intended when I captured the data. BlurXterminator for sharpening, StarXterminator to allow stars and nebula to receive their own processes, and NoiseXterminator to clean up.

I even tried GHS stretch but found a much simpler solution to stretch the nebula. After star removal, I simply used Histogram Transformation ("levels" in PS) to bring in the white point and black point for each channel separately (avoiding clipping). After that, some local contrast enhancement and colour saturation boost. Then brought the stars back in (stretched with masked stretch).

I goofed around with the data some more and found a simple way to fake a Hubble SHO palette. If you have a standard HaRGB image, you simply invert it, apply SCNR green, and invert it back. Voila!

The result was a little too "mustard" for my taste, so I blended 50-50 with a version in which I used PixelMath to mix the channels of the original image.

Red: $T[0]

Green: 0.8*$T[0] + 0.1*$T[1] + 0.1*$T[2]

Blue: (2*$T[2] + $T[1])/3

Personally, I like the natural look of the HaRGB image better.

Btw, that blue patch int middle of the image is not an artefact. It shows in Aladin's SDSS plates. But I couldn't find a reference or ID for it.

>>

Posted 14 hours ago (edited)

Still no astro darkness for another two to three weeks. So, apart from tinkering in my observatory and things to do around the house, I'm reprocessing old data with new tools in the PI toolkit.

This is data that I collected back in 2021, Melotte 15. The Xterminator suite of processes allowed me to create a version that is closer to what I had intended when I captured the data. BlurXterminator for sharpening, StarXterminator to allow stars and nebula to receive their own processes, and NoiseXterminator to clean up.

I even tried GHS stretch but found a much simpler solution to stretch the nebula. After star removal, I simply used Histogram Transformation ("levels" in PS) to bring in the white point and black point for each channel separately (avoiding clipping). After that, some local contrast enhancement and colour saturation boost. Then brought the stars back in (stretched with masked stretch).

 

>>I goofed around with the data some more and found a simple way to fake a Hubble SHO palette. If you have a standard HaRGB image, you simply invert it, apply SCNR green, and invert it back. Voila!<<

What an absolutely brilliant trick!  I had a go on your image and it works a treat! (hope you don't mind).  I will put this in my toolbox.

 

[wimvb]

3 hours ago, alan potts said:

Superb as usual and Olly saying that tells us all something.

Alan

 

3 hours ago, Lee_P said:

There are corkers, good job!

 

2 hours ago, simmo39 said:

V nice! Getting me in the mood for darkness!

Thank you very much, all.

[wimvb]

2 hours ago, windjammer said:

What an absolutely brilliant trick!  I had a go on your image and it works a treat! (hope you don't mind).  I will put this in my toolbox.

(Don't mind at all.) I'm glad you find it useful. SCNR removes one of the primary colours, red, green or blue. If you invert an image first, it removes the corresponding complementary colour, cyan, magenta, or yellow. In this case, the image didn't have much bright and solid red in it, as many Ha images tend to have. That's why it was easy to remove the dominant red/magenta and get something which looks like a Hubble palette.

[gorann]

What a superb way to keep up your processing skills while we wait for astrodarkness here in Sweden! Yes, I also go for the ketchup version over the mustard.

[wimvb]

Thanks @gorann. Just a few more weeks ...