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Hey everyone,

I'm having some issues processing my Andromeda galaxy. Try as I might I can't really get any colour to the galaxy. If I really intensely stretch the vibrance and saturation then I can get a nice orange core. But the dust lanes are always so, so brown. Try as I might I can't get them to be accurate colours really. 

I'm not sure the issue. I'm pretty sure my light pollution (Bortle 6) doesn't help anything. But I've seen other images from OSC cameras in heavier pollution with much better results. I'm not sure what to do in my processing to try and sort this out and I've attempted it several times. Anybody help?

Integration Details

224 x 120" lights 7.46hrs

Flats, Dark Flats and Darks

ZWO ASI 071mc Pro

IDAS NGS1 Filter

Sky-Watcher Evostar 80ED + Reducer

Deep Sky Stacker & Affinity Photo

 

I originally felt like the light pollution filter is to blame. Looking at the transmission it could be blocking a bit in the middle of the spectrum and more of the blues. Making for quite a magenta/brown image. But again I'm fairly certain I've seen people using LPS filters to great effect. 

 

Any input greatly appreciated. I feel I'm quite capable on processing so don't worry about not using techincal terms etc.

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I don't do any real AP (yet) but it looks like a nice clean image, very sharp with low noise. I imagine the white balance just needs a bit of a tweak, good work though, that's a long integration time! 

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To me that looks like the 'natural' colouration for M31, I dont see why you would want to get an orange core. The NGS1 filter also removes most of the spectrum between 550 and 650 nm so there goes all the yellows and oranges.

Edited by Seelive
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You can fiddle around with your version a bit, but it is hard to produce image looking like this other you posted for several reasons (filter use is one).

Here is what a quick reprocess gives:

demo.jpg.d6aa201d4f2bc9b1513c3ba71ddcced5.jpg

I guess that is more to your liking than original image?

I just used Gimp to bring background to same level thus removing slight blue cast on background sky and then used Nik collection color effects - remove color cast, to remove reddish cast on the image.

Better way to do it would be to remove background while image is still in linear stage and then see about color cast ...

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demo2.jpg.96527aa50a4acbedd62396a8f4123f4f.jpg

almost there after some fiddling with color channel mixer and saturation in Gimp - but that gradient is a killer ...

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I'm sorry but I don't see anything natural about the colour. The image, as it stands, strikes me as pretty monochromatic. (Not greyscale as in black and white but a kind of monochrome brown, monochrome meaning 'single colour.') As it stands, the colours are not being distinguished or separated. Look at the star colour. To my surprise, when I measured the sky, I found it was low in blue, not red. I was expecting the opposite.

Vlaiv is getting there with the galaxy but the background needs to be neutralized. In my view a background sky should be at parity between red, green and blue.

Olly

 

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2 hours ago, ollypenrice said:

 

I'm sorry but I don't see anything natural about the colour. The image, as it stands, strikes me as pretty monochromatic. (Not greyscale as in black and white but a kind of monochrome brown, monochrome meaning 'single colour.') As it stands, the colours are not being distinguished or separated. Look at the star colour. To my surprise, when I measured the sky, I found it was low in blue, not red. I was expecting the opposite.

Vlaiv is getting there with the galaxy but the background needs to be neutralized. In my view a background sky should be at parity between red, green and blue.

Olly

 

Hi Olly

Yeah that was part of the reason why I asked about how people go about editing M31. I usually find it very monochromatic and brown when I've edited them so I was wondering if anyone had any procedures to assist.

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9 hours ago, AstroRuz said:

Hi Olly

Yeah that was part of the reason why I asked about how people go about editing M31. I usually find it very monochromatic and brown when I've edited them so I was wondering if anyone had any procedures to assist.

The ultimate weapon against gradients is Dynamic Background Exraction in Pixinsight but there are other gradient tools. Gradient Xterminator for Ps, AstroArt, has one, as does Astro Pixel Processor. I'm sure there are others, too.

There was a long discussion about galaxy colour on here during which Vlaiv convinced me that the 'red core-blue arms' thing is usually over-done by amateurs. It was only latent in my own data so I adjusted  for less colour differentiation and less saturation as well. This colouration was influenced the Hubble image to which Vlaiv linked in the conversation. https://www.astrobin.com/full/dx6n5x/0/

Olly

Edited by ollypenrice
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2 hours ago, ollypenrice said:

The ultimate weapon against gradients is Dynamic Background Exraction in Pixinsight but there are other gradient tools. Gradient Xterminator for Ps, AstroArt, has one, as does Astro Pixel Processor. I'm sure there are others, too.

There was a long discussion about galaxy colour on here during which Vlaiv convinced me that the 'red core-blue arms' thing is usually over-done by amateurs. It was only latent in my own data so I adjusted  for less colour differentiation and less saturation as well. This colouration was influenced the Hubble image to which Vlaiv linked in the conversation. https://www.astrobin.com/full/dx6n5x/0/

Olly

That's a really nice image you have at the end. I don't have Pixinsight and really I've found Gradient xterminator hit and miss. I do agree that the red core blue arms is very easy to overcook. I think I did that also but least I'm kind of getting the colours how I want now. 

Maybe toning down the colours a bit is on the agenda

 

 

IMG_20210112_192520_055.jpg

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41 minutes ago, AstroRuz said:

That's a really nice image you have at the end. I don't have Pixinsight and really I've found Gradient xterminator hit and miss. I do agree that the red core blue arms is very easy to overcook. I think I did that also but least I'm kind of getting the colours how I want now. 

Maybe toning down the colours a bit is on the agenda

 

 

 

You're getting there. The spiral arms are now very magenta, meaning the greens are too low. The sky top left is pretty good but the lower right has a magenta bias as well.  It's a long time since I used Grad X but, from memory, the trick is to exclude objects and stars from the sample you give it. In Ps I'd probably use the colour sample tool to select background sky.

Olly

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