IC1805 - The Heart Nebula - 2 pane mosaic in HaRGB

[jjosefsen]

Good evening,

This is a product of me really experimenting with processing workflows and applications.

With this image I used Astro Pixel Processor (new to me), PixInsight and Photoshop (also new to me), for various parts of my workflow.

More detailed explanation of the the processing workflow and acquisition details can be found here: Astrobin

It is a 2 pane mosaic of Halpha and RGB totalling 10,1 hours of exposure.

 

I would very much like CC on this, particularly tips and tricks in regards to processing.

I might create another thread with ramblings about PixInsight vs APP vs PS and how I realised I was actually quite bad at processing.

 

I am still not at the stage where I feel I can leave an image up at 100% scale, so to hide some of the noise this image has been resampled to 50%. Maybe with better processing skills and perhaps a cooled camera..

[sloz1664]

You've got some nice detail within the image which looks very nice indeed. It's a pity you have not captured the whole of the Heart, but that can be added at a later stage. 

Regarding the difficulties in processing I think you have part answered your own question in finding it difficult processing. Trying to master Astro Pixel Processor, PixInsight and Photoshop  is a very difficult challenge indeed.

Steve

[Sunshine]

Wonderful image it is!

[tooth_dr]

Yes that’s another league altogether. Fantastic 

[jjosefsen]

15 minutes ago, sloz1664 said:

You've got some nice detail within the image which looks very nice indeed. It's a pity you have not captured the whole of the Heart, but that can be added at a later stage. 

Regarding the difficulties in processing I think you have part answered your own question in finding it difficult processing. Trying to master Astro Pixel Processor, PixInsight and Photoshop  is a very difficult challenge indeed.

Steve

Thank you. I realise that it might seem counterintuitive to throw even more applications into the mix. But I found that PS offers a much more WYSIWYG experience, compared to the often math based approach of PI.

APP is just super simple to use and I think I'm going to end up buying it, very easy to get good results with it.

[sloz1664]

10 hours ago, jjosefsen said:

Thank you. I realise that it might seem counterintuitive to throw even more applications into the mix. But I found that PS offers a much more WYSIWYG experience, compared to the often math based approach of PI.

APP is just super simple to use and I think I'm going to end up buying it, very easy to get good results with it.

I've been using APP for over 18 months and found it the best pre-processing software I have used.

Steve

[jjosefsen]

51 minutes ago, sloz1664 said:

I've been using APP for over 18 months and found it the best pre-processing software I have used.

Steve

I agree.. It completely nailed this mosaic. Had I known that it would work this smoothly I would have gone for the full 4 panels. ?

[tomato]

Wonderful image, for someone wrestling with the processing software packages, that's a great result.

+1 for APP, I too have found it excellent for calibration and it seems to work miracles combining data taken on different set ups, and making mosaics,  again using data from different sources.

I am also increasingly using the image  processing functions, with some degree of success when compared to Startools.  I don't have PI.

 

Steve

[ollypenrice]

I like the image but feel that, somewhere along the line, too much Ha has found its way into the luminance component. (I call it a 'component' because it ceases to be a channel once the image is in RGB mode.) This is why it is such a pale pink colour and why your blue stars are ringed with blue/magenta. We used to see this all the time maybe 7 or 8 years ago when imagers, unsure of what to do with their Ha, used it as luminance. It went out of fashion when people started using Ha to lighten the red channel in Ps Blend Mode Lighten or Blend Mode Screen (which needs some clipping to work.) If you do it this way you can remain very close to the colours of the RGB image when you add the Ha. This seems to me to be what we ought to be doing. The Ha is there to find faint signal and carve defined structures in the red hydrogen emission. It should not be allowed to change the colour - in my view.

I've seen a few APP HaLRGB images tending towards the pink. I don't know what means it uses to combine Ha but I'll be sticking with blend mode lighten when adding it to red in Ps.

Olly

[jjosefsen]

59 minutes ago, ollypenrice said:

I like the image but feel that, somewhere along the line, too much Ha has found its way into the luminance component. (I call it a 'component' because it ceases to be a channel once the image is in RGB mode.) This is why it is such a pale pink colour and why your blue stars are ringed with blue/magenta. We used to see this all the time maybe 7 or 8 years ago when imagers, unsure of what to do with their Ha, used it as luminance. It went out of fashion when people started using Ha to lighten the red channel in Ps Blend Mode Lighten or Blend Mode Screen (which needs some clipping to work.) If you do it this way you can remain very close to the colours of the RGB image when you add the Ha. This seems to me to be what we ought to be doing. The Ha is there to find faint signal and carve defined structures in the red hydrogen emission. It should not be allowed to change the colour - in my view.

I've seen a few APP HaLRGB images tending towards the pink. I don't know what means it uses to combine Ha but I'll be sticking with blend mode lighten when adding it to red in Ps.

Olly

See I was trying to figure out how to do this because you and Ciaran were talking about it, but I can't seem to figure it out.

I don't think I can blend anything when i'm in  the channels tab, so I ended up making a new R channel with Ha and R data, and as you say using the Ha as luminance.

Do I need to do it before i create the RGB master? Or is it some kind of color adjustment layer?

[jjosefsen]

I must admit that I don't shoot much L at all, I might have to change that..

With the weather being what it is, I tend to shoot all the RGB that I can when the moon is away and it is clear, and the rest of the time it is Ha.

So often the Ha is much cleaner due to increased integration time and less lightpolution, this makes it very tempting to use it as luminance to tease out the details.

[gorann]

32 minutes ago, jjosefsen said:

See I was trying to figure out how to do this because you and Ciaran were talking about it, but I can't seem to figure it out.

I don't think I can blend anything when i'm in  the channels tab, so I ended up making a new R channel with Ha and R data, and as you say using the Ha as luminance.

Do I need to do it before i create the RGB master? Or is it some kind of color adjustment layer?

Nice image with potential! When you add Ha to the red channel you do this in PS by adding it as a layer to the red channel and then chose Lighten (not Luminocity) as blending mode. This means that Ha is added only where it brightens up the red channel. When you use it as Lum on top of an RGB image as you have done you get this salmon-pink red colour and since the stars are usually thighter in Ha you get blue rings around blue stars. I have sometimes also added some Ha as lum (in addition to adding it to the red channel) since Ha is often she sharpest colour, but then I usually blend it in with a lower percentage than 100 %. Using things like Selective Color and Hue/Saturation in PS can correct the pink but it is not ideal. To reduce blue rings you can try separate out the blue channel and shrink the stars in that channel before you put it back in.

[jjosefsen]

15 minutes ago, gorann said:

Nice image with potential! When you add Ha to the red channel you do this in PS by adding it as a layer to the red channel and then chose Lighten (not Luminocity) as blending mode. This means that Ha is added only where it brightens up the red channel. When you use it as Lum on top of an RGB image as you have done you get this salmon-pink red colour and since the stars are usually thighter in Ha you get blue rings around blue stars. I have sometimes also added some Ha as lum (in addition to adding it to the red channel) since Ha is often she sharpest colour, but then I usually blend it in with a lower percentage than 100 %. Using things like Selective Color and Hue/Saturation in PS can correct the pink but it is not ideal. To reduce blue rings you can try separate out the blue channel and shrink the stars in that channel before you put it back in.

I will try again, I must have missed something..

Thank you for the explanation.

[ollypenrice]

So the individual Ps steps are:

Select and copy (Ctrl A Ctrl C) the co-registered Ha.

Activate the RGB and go channels - split channels - and activate the red channel

Paste the Ha onto the red (Ctrl V)

Change blend mode to Lighten.

Assess its effect on red. If it's not doing enough, work it in Curves. Keep the bottom down so as not to redden the sky but stretch above that.

Flatten (Ctrl E)

Go to channels, merge channels (RGB) and simply put red (now modified) in red, green in green, blue in blue and apply.

Too much Ha? Not a problem: paste the HaLRGB on top of the original LRGB and choose the opacity you like.

Olly

[jjosefsen]

3 hours ago, ollypenrice said:

So the individual Ps steps are:

Select and copy (Ctrl A Ctrl C) the co-registered Ha.

Activate the RGB and go channels - split channels - and activate the red channel

Paste the Ha onto the red (Ctrl V)

Change blend mode to Lighten.

Assess its effect on red. If it's not doing enough, work it in Curves. Keep the bottom down so as not to redden the sky but stretch above that.

Flatten (Ctrl E)

Go to channels, merge channels (RGB) and simply put red (now modified) in red, green in green, blue in blue and apply.

Too much Ha? Not a problem: paste the HaLRGB on top of the original LRGB and choose the opacity you like.

Olly

Ahhh I found out where I went wrong, I did not know about the split channels function.

I am tinkering with it now, and it certainly does look more natural, but alot of the nice details from the Ha is missing.

I really must try to get a good stack of luminance and see how that affects the overall image, like I said I haven't really shot any luminance since I got this mono cam.

This false luminance is maybe a bit too noisy and lacking in detail..

[Allinthehead]

If you can integrate the ha as Olly described i think you'll have a great image. Everything else is there.

[jjosefsen]

With the Lighten Red method, and a synthetic luminance from the Ha brightened RGB.

More details, but also more noise and stars are ballooning again.. So hard to get it right..

 

 

[Ruud]

A wonderful image! I quite like the stars. You have lots of white and blue ones with a few yellow stars between them. That looks very nice.

[ollypenrice]

Much better for me. This will also help, I think: in Ps go to Selective Colour which will open in the reds. Move the top slider left to lower the cyans in red. This is a classic little trick.

You can always apply the Ha at very low opacity as luminance and then adjust the colour under it.

Olly

[jjosefsen]

7 minutes ago, ollypenrice said:

Much better for me. This will also help, I think: in Ps go to Selective Colour which will open in the reds. Move the top slider left to lower the cyans in red. This is a classic little trick.

You can always apply the Ha at very low opacity as luminance and then adjust the colour under it.

Olly

I will try this. Except for the stars then I also like this version, certainly more natural looking. I am looking into maybe separating the nebulosity from the stars and the processing them independently..

Do you shoot luminance for all your emission nebulae? Seems like some people think it is a waste of time.

But if I want to use the RGB for a synthetic lum, then I think I need to shoot much more of it.

Thank you for taking the time to comment (all of you) it is greatly appreciated.

[ollypenrice]

I have mixed feelings about L for emission nebulae. (It's a must for dust and reflection.) My co-conspirator Tom O'Donoghue always takes L. He reckons it tightens things up and I guess it often does.

However, if the target is dominated by Ha and OIII and has a very desnse starfield to control I may just shoot RGB and process it with a soft stretch to keep the stars small and colourful. I'll then let the Ha and OIII do all the work on the nebulosity by adding Ha to red and OIII to green and blue. In this case the RGB is just a medium to carry the narrowband and provide star colour. I'd be reluctant to do this with only Ha and RGB because you end up with an image whose interest is confined to the red channel and this doesn't give a very three-colour-dimensional look.

Olly

 

[Spaceade]

Lovely and sharp jjosefsen, working on a heart myself ? 

[carastro]

I agree with Olly's comments, but then he did teach me this method in the first place.  

I must admit though I do sometimes also add the Ha as luminance as well (depending on the target)  just to sharpen up the detail, but I don't add this at 100% and normally have to adjust the colour to compensate.

Very nice image though. 

Carole 

[Adam J]

Its strange, but my eye always hunts out the detail first and the color balance second, hence I like the original as it has better definition. I find that over saturating the RGB layer before adding Ha Luminescence is the way to go. 

Hence Ha(Ha+R,G,B)

Adam

[jjosefsen]

Had another go at this the last week, trying to be more "true" to colors, while trying to still get some of the details from the Ha data.

Stacking in APP again, all post processing done in PixInsight.

I've definately learned some new ways to blend data with PixelMath in PI, and oddly enough, working a little in PS has helped me understand what happens in "PixelMagic"

So this time the red channel was mixed with Ha, likewise an amount of Ha used to enhance the synthetic luminance from the combined RGB.

 

Next up might be completely removing the stars R,G,B and Ha masters and the adding RGB stars later..

As usual I find that getting good stars is a problem, even when trying to protect them a lot when stretching. In this case some of the larger / blue stars are quite overexposed..

Mr. @ollypenrice what do you think about this version? Better? Still got some wonky blue stars, but this time I don't think it is because of the Ha, but probably because the only color left is in the halo..