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Lagoon Nebula Hubble Pallet Attempt and Advice

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#1 Afederl

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Posted 04 July 2020 - 07:51 PM

How's it going all,

 

I recently re-processed some data on the Lagoon nebula and chose a Hubble type pallet for the colors. For the most part I am pretty happy with it - there are just some questions and hopeful advice I'm looking for.

 

Attached you can see the images. The problems I have with the photos are they look great on a mobile (iPhone 11) display, but on a computer monitor, you can see the splotches of different colors that aren't associated with any nebulosity in the starry areas, I'm assuming from the different color channels. Is there an effective way to make the background black while still keeping the nebula detail? 

 

Another point I want to discuss are the different ways of using what I assume would be a starmask, through Photoshop. I have read that many people will use the StarNet++ like I do, then go back and add the stars back in to make a better looking image - something I think would help since there are so many stars in the image. Again, any tutorials or workflows for that would be super helpful! 

 

Thanks all!

Attached Thumbnails

  • lagoon Final Hubble.jpg
  • Lagoon Starless Hubble.jpg

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#2 sunnyday

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Posted 04 July 2020 - 08:14 PM

superb shots and work , thanks .



#3 Huangdi

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Posted 04 July 2020 - 08:18 PM

How's it going all,

 

I recently re-processed some data on the Lagoon nebula and chose a Hubble type pallet for the colors. For the most part I am pretty happy with it - there are just some questions and hopeful advice I'm looking for.

 

Attached you can see the images. The problems I have with the photos are they look great on a mobile (iPhone 11) display, but on a computer monitor, you can see the splotches of different colors that aren't associated with any nebulosity in the starry areas, I'm assuming from the different color channels. Is there an effective way to make the background black while still keeping the nebula detail? 

 

Another point I want to discuss are the different ways of using what I assume would be a starmask, through Photoshop. I have read that many people will use the StarNet++ like I do, then go back and add the stars back in to make a better looking image - something I think would help since there are so many stars in the image. Again, any tutorials or workflows for that would be super helpful! 

 

Thanks all!

First of all, nice image!

 

I know the frustration of having different screens. My images usually look amazing on my laptop, but awful on my phone. Once I correct the colors on my phone, they look odd on my laptop...idk.

 

I would add that the background should never be black. It should be dark grey, but if it is black you are clipping data (turning signal into nothing essentially). I understand that it might seem that this helps with noise, but that's not the case. 

 

If you stretch your data too far without having sufficient signal, it is going to look grainy.  There are two ways to get rid of the grain. 

 

1. Use noise reduction

2. get more data 

 

Either way, using starnet is a good choice, I can't process non-narrowband images without it anymore. I usually stretch the data to reveal the medium-bright details. Then I separate the stars from the sky using Troy's Astro Actions for photoshop (free) and run it through starnet.

 

After starnet, use the clone stamp tool to get rid of any unwanted artefacts from the star removal process, then proceed to stretch the image further to reveal the faint bitsies. 

 

Last but not least, use the blend mode "linear dodge add" to blend them over the image. Usually this will result in mediocre looking stars, that's why I apply a gaussian blur (anything between 0.1 and 1px) to smoothen the stars out. Increase saturation on them if they lack color and that should leave you with a nice image that isn't overwhelmed by stars!



#4 BQ Octantis

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Posted 04 July 2020 - 11:00 PM

G'day mate,

 

You already have a star image to paste as a layer on top of the starless image. Just switch the star layer's mode to Lighten, and you can use Curves on that layer to bring down the stars to whatever amount you want in the image:

 

animation.gif

 

Since the starless lagoon came from the same image, lowering the starred image with Curves will just reduce the stars and not the nebula.

 

BQ


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#5 BQ Octantis

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Posted 05 July 2020 - 01:56 AM

To your first question, you can eliminate the background colors by making a mask for your nebula layer with the following workflow:

 

  • Duplicate the nebula layer (and select the duplicate)
  • Image → Adjustments → Desaturate
  • Levels → Gamma = 9.99, step the black point up until the background is clipped to the edge of the nebula

screenshot1.jpg

  • Filter → Blur → Gaussian blur… → 2.0 pixels
  • Levels → Drop the white point until the nebula is all white (you can verify with a test gamma of 0.01)

screenshot2.jpg

  • Image → Adjustments → Invert
  • Select → All → Edit → Copy
  • Turn off the layer's visibility
  • Duplicate the nebula layer again (and select the new duplicate)
  • Add layer mask
  • In the Channels window, select the layer mask channel and turn on its visibility
  • Edit → Paste

screenshot3.jpg

  • Turn off the layer mask channel visibility
  • Select the RGB channel

Now you have a layer with the nebula masked off. You can either go Image → Adjustments → Desaturate or use Hue/Saturation to reduce the saturation to the level you want. If you then paste in the star layer, just clip the star background a little bit so the lighten doesn't bring back the noise.

 

Cheers,

 

BQ

 

 


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