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konstantinos75

Help, please, with M31

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Hello
 
I have tried to process some data of M31 I took last year multiple times and I cannot seem to optimize the colors and detail in my final image. Here is the best I have been able to come up with:
 
http://albireo.gr/astrogallery/galaxies/2015.09.18/M31.html
 
I am using Pixinsight from beginning to the end.
 
Could someone give me any detailed guidance how to process M31 properly with Pixinsight or any other program (e.g. Photoshp, ccdstack..)  and have comparable results to these images:
 
http://www.starkeeper.it/M31BridgeM110_Mid.htm
http://bf-astro.com/m31/m31big.htm
http://www.billionsandbillions.com/andromeda.html
http://astrofotky.cz/gallery.php?show=Konihlav/1414773348.jpg
http://www.astrovox.gr/forum/album_pic.php?pic_id=13424
 
Here you can download the master L,R,G,B,Ha frames. They are aligned and no other processing has been done.
 
https://www.dropbox.com/s/mbwzc6u5jjqj3e3/M31_data.zip?dl=0
 
 
Thank you
Konstantinos

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Wonderful image Konstantinos - I love the colours and you have great detail in M31.

( Sorry I can't help with processing tips that might make it even better as I only know a little bit and what I do know is limited to full colour DSLRs )

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You don't want my help with that! :icon_biggrin:   Fantastic image and something that I'd love to be able to replicate.

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It is a great image as is. I think that the "look" of various renderings is not just dependent on processing, but also on sky conditions and gear.

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Hello Constantinos - that's a fantastic image and there's obviously plenty of detail there so it's well worth being persevered with.

But .... personally (and of course all such views are personal and highly subjective) I prefer M31 a little less colourful.  If it were me I'd tone down the blues and pinks.  Nevertheless many others would disagree with me, as is obvious from the number of highly colourful M31s we see these days.  

Now my problem is the exact opposite of yours. My M31s always look too drab colour-wise. But that's a seperate story. 

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I had a closer look at your image, and the LHaRGB data. Your image of M31 has a stronger blue colour near the core than is usual. This may be due to the way you combined the different channels. You will probably need to experiment to find the proper combination of red and Ha. One way to test is to use PixelMath to combine the channels:

http://www.lightvortexastronomy.com/tutorial-combining-monochrome-r-g-and-b-images-into-a-colour-rgb-image-and-applying-luminance.html#Section2

(scroll down to the image of the North America Nebula, where pixelmath is used for narrowband combination)

PixelMath will give you more flexibility during combination than other tools in PI.

 

Hope this helps,

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Hi
 
Thank you all for your contribution to this post.
 
I have tried to reprocess the data.
 
Step1) align the master L,R,G,B,Ha frames with reference image the master L
Step2) resample all master frames to 50%
Step3) dynamic crop to remove black edges
Step4) ABE on each channel to remove gradients
Step5) Linear fit on each channel with reference the Ha file to in order to match the brightness intensities
Step6) produce the RGB image
Step7) DBE to the RGB
Step8) Background neutralization and color calibration
Step9) Curves to increase saturation and SCNR after that
Step10) produce the HaRGB
Step11) Stretch the HaRGB
Step12) DBE and stretch the master L
Step13) generate the HaLRGB
Step14) create masks
DEAL WITH THE STARS
DEAL WITH THE BACKGROUND
DEAL WITH THE GALAXIES
TGV Denoise
multiscale sharpening
 
Here you can download the detailed descriptions of my steps:
https://www.dropbox.com/s/ukkkmfedwmhwqka/M31_PROCESSING_NEW_BEST.docx?dl=0
 
Here you can see the full size M31
http://albireo.gr/astrogallery/galaxies/2015.09.18/M31.html
 
I have come to the conclusion that to get a better results its a matter of equipment (camera,filters,telescope...) and night sky darkness.

M31.jpg

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It's a great image in its own right. It's very well processed.

Thanks for sharing.

Btw, as you are using PixInsight, Vicent Peris has a video tutorual explaining a possible workflow.

https://pixinsight.com/videos/NGC1808LRGB-vperis/

There are also scripts for combining rgb with nb. I tried it one on your image, but wasn't satisfied with the result. (The script is ok, but I have no experience of nb imaging.)

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Hi

I know Vicent Peris method for LRGB combination but it does not work successfully with my M31 data.

At the end is a matter of experimenting until you come up with a solution you are satisfied.

Try, try again and practice makes perfect :)

 

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I'm currently also processing M31 with PixInsight ^^

I don't have much experience, but it seems your photo could get some help from a deconvolution at the linear stage and some HDRMultiscaleTransform & LocalHistogramEqualization later on.

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I tried bith HDRMT and LHE on Konstantinos image. It's easy to overdo this. I got better results with both when using a 50% mask. This would take some massive experimenting (for me at least, as I'm not familiar with lrgb imaging)

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