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Help with these gradients


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Hi All,

In dire need of some help here.

I seem to really struggle with processing these (purple, blue, brown) gradients out of the image using Pixinsight.

Just a bit of a background to this image. I ran DBE on all individual channels, then star aligned, ran a bit of noise reduction and combined them. Used STF, used the stf value to HistrogramTransformation Tool and applied. Used ColourMask script for Magenta (to reduce purple stars), Green to tone down the Green a bit and then Blue to up the blue a bit. 

Would really appreciate if i can have some pointers. 

In case if anyone wants to have a go at the data, here's the link to the xsif (i hope that's ok) file.

https://1drv.ms/f/s!AqwJUE4hC6abgV_LuH6gcBVy_GeM

Thanks

 

 

soul.jpg

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3 minutes ago, LightBucket said:

Gradient xterminator would take care of those....but a little pricey

There is also a PS pluggin by Pro Digital software, that is also very good, for around £23 here, it’s called Astro flat...

http://www.prodigitalsoftware.com/Products.html

Cheers for the link mate but I'd like to deal with these in Pixinsight if possible as this is the software that I have right now so want to make full use of its potential. Also I know PI is more than capable of dealing with this but I just need to find out that way :)

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Hi, I have PI for a few months only... Not a pro,

but I was interested to give a try.

1) Extracted Luminance > Curves (S form, to reduce background and brighten the central nebula a bit) > Deconvolution (with star mask as ref and masked with the same luminance adjusted with curves in the same manner).

2) LRGB combination (Blended back Luminance to the main sub)

3) Curves>LocalHistogramEqualizatin>HDRMultiscale transfrom..

However, I was not able to remove the gradient completely... I do think you have a very noisy OIII and this sub has to be adjusted separately or taken in a darker skies maybe... Or reduce the amount of OIII while blending.

Image27_clone.xisf

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14 hours ago, RolandKol said:

 

That's a very fine effort mate.

11 hours ago, Allinthehead said:

On my phone so i can't see what gear you're using but is it possibly amp glow? 

Have you calibrated properly?

Richard.

I'm using WO Star 71 with ASI1600MM. Yes amp glow is a problem but i'm not too fused about that. It's these weird blueish, brownish and sometime purplish gradients that i have an issue figuring out

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59 minutes ago, souls33k3r said:

That's a very fine effort mate.

I'm using WO Star 71 with ASI1600MM. Yes amp glow is a problem but i'm not too fused about that. It's these weird blueish, brownish and sometime purplish gradients that i have an issue figuring out

As I mentioned before, try to reduce OIII amount in PixelMath (Use *0.8 or even 0.5)

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2 minutes ago, RolandKol said:

Waiting for your final result! :) curious! :) as I have started Mono only a few weeks ago.

My OIII are also very noisy... (taken from Woolwich) - I bit too light for OIII in our areas... :(

Processing is fun mate but i'm a half perfectionist and like to know how to deal with issues hence the reason why the post. 

I'd still want to find out if there's anything else i can do besides using PixelMath and adjusting the amount of channel integration. 

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1 minute ago, souls33k3r said:

Processing is fun mate but i'm a half perfectionist and like to know how to deal with issues hence the reason why the post. 

I'd still want to find out if there's anything else i can do besides using PixelMath and adjusting the amount of channel integration. 

In such a case, post all 3 stacked subs per Filter and wait for PI Ninja to show up :)

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Unfortunately it is too late but then i've always avoided flats. I only have an iPad which i've tried it in the past but as soon as i place the iPad over the top of our WO Star 71, the white torch light application goes all wonky even after putting 3/4 sheets of thick white paper over it. 

Is there a way to deal with this issue without flats? :(

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I had a look at your data. There're severe gradients in the Oiii and Sii stacks as you already know. 

I used a great tool in Astro Pixel Processor called light pollution removal and it helped a lot. Gradient Exterminator was also used. Dbe should give similar results. Do you use dithering between subs?

1263058974_soulsfinal.thumb.jpg.38a6d2efe95f4dc059c380899a075458.jpg

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6 minutes ago, Allinthehead said:

I had a look at your data. There're severe gradients in the Oiii and Sii stacks as you already know. 

I used a great tool in Astro Pixel Processor called light pollution removal and it helped a lot. Gradient Exterminator was also used. Dbe should give similar results. Do you use dithering between subs?

1263058974_soulsfinal.thumb.jpg.38a6d2efe95f4dc059c380899a075458.jpg

What the actual ... :confused2: ... this can't be my data surely ... i mean, i would kidnap 2 kittens and never ever return them to have an end result like that (or at least to begin with) 

Unfortunately i don't have APP or Gradient Exterminator but man you've really cleaned up this data nicely.

I've tried everything i possibly know with DBE but i couldn't get rid of it so surely i'm not using PI to it's full potential.

Now we know the data can be cleaned up, all i want to know how to do with PI now :( man i'm super jealous with what you've got and were able to do. Too good mate.

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7 minutes ago, souls33k3r said:

I've tried everything i possibly know with DBE but i couldn't get rid of it so surely i'm not using PI to it's full potential.

I've asked people who use both DBE and Grad X and DBE seems to be the superior tool. How much integration time did you get with each filter and did you dither between subs?

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1 minute ago, Allinthehead said:

I've asked people who use both DBE and Grad X and DBE seems to be the superior tool. How much integration time did you get with each filter and did you dither between subs?

Sorry you did ask me that. Yes I do dither but I guess every 5 frames. Will be able to confirm that to you when I get home but I think it's every 5 frames. 

Each channel is almost 2hrs of data (20 x 5 min) 

Much appreciated for asking around for us mate, I really can't thank you enough. Its a puzzle I'd like to resolve and understand more in order to remotely reach the results you were able to produce. 

DBE is indeed the most favourable tool around and since I've only got PI, I sort of stuck with this option only. 

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I dither very 5 frames too, seems to do the trick. If i were you i'd aim for at least 5 hrs per filter especially Oiii and Sii as i've found these to be noisy with the Asi 1600. 

I downloaded your jpg above and used SCNR green and DBE on it and got this. I reckon your attempt is actually over stretched. Try to hold back to about 60% in each channel and see what you end up with, less is more sort of deal.

souls_DBE.thumb.jpg.cdc0cf10f2d61bc2a8a891803073e9c8.jpg

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