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Andromeda Help

Request for feedback M31 Galaxy Messier Objects
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Benjamin DeHaven avatar
Benjamin DeHaven avatar
I am trying to figure out if my data is bad or my editing process is bad (or both). I'd love some feedback. Attached you will find my best edit, it is about 3 hours of data with a Nikon D850 unmodded and a Nikon 200-500mm  at 500mm f5.6. I use 5 minute exposures at ISO 400. I know galaxies aren't supposed to be green... I have the trial of Pixinsight but am having trouble figuring it out so this is edited in good ole Photoshop. I see these beautiful Andromeda's on here with gorgeous blues and peaches and I for the life of me cannot get my data to do that. So basically, where do I need to improve the most and what can I do?



M31 - Andromeda Galaxy

This is my original, stacked but unedited if you feel like taking a look or even editing it...

https://drive.google.com/file/d/1jQI2CgHzvh-xA-hfyx9nQIt1FKwFxYY7/view?usp=sharing

Thanks!

Benjamin
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Shawn avatar
Shawn avatar
PixInsight's SCNR does a good job removing the green cast.
https://www.chaoticnebula.com/pixinsight-scnr/
Michael M avatar
Michael M avatar
To remove the green cast you can use SCNR in pix. I’d also recommend hue-saturation adjustments. Im sure they exist in pix
Ian McIntyre avatar
Ian McIntyre avatar
This method for color calibration on Shawn Harvey's video works great. Start at 4:03
https://youtu.be/Xl036NZ3Eoc

He also uses SCNR later in the video.
Andy Wray avatar
Andy Wray avatar
I had a quick bash at improving the colours.  Photometric colour calibration in Pixinsight, a 60% SCNR green noise reduction and some hue and chrominance tweaks in curves.  Your data looks pretty good from what I can see, so maybe just a bit more time spent on colour calibration.
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andrea tasselli avatar
andrea tasselli avatar
That's a correctly coloured image in the main, broadband images of M31 should show a yellow-green cast if you use standard umodified DSLR (NIKON) and use photometric colour balance in PI. You would need to tweak the hue curve in PI to remove the green cast (but do not expect those H-alpha reds to show!) and please, do not use SCNR, that is for the background only. I might try to give it a more pleasing colouring if I find the time later on.
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andrea tasselli avatar
andrea tasselli avatar
I had a quick look and apparently the image you posted isn't calibrated, certainly not flat-calibrated. You're not going very far without proper calibration I'm afraid.
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Benjamin DeHaven avatar
Benjamin DeHaven avatar
andrea tasselli:
I had a quick look and apparently the image you posted isn't calibrated, certainly not flat-calibrated. You're not going very far without proper calibration I'm afraid.

Thats odd, I took some flat frames and threw them into the mix in DSS. I assume that's what you are referring to. Still a beginner so forgive me if I misunderstood you. I will take more flat frames next time. Thank you.

Benjamin
Steve Cooper avatar
Steve Cooper avatar
I tweaked the color some in Pixinsight then used the Photometric color calibration tool. Also used the HDMR Multiscale Transformation tool with a mask to bring out the dust lanes more. 
Benjamin DeHaven avatar
Benjamin DeHaven avatar
Here is my latest attempt based on what I could do in Photoshop with the Pixinsight advice which I couldn't figure out how to implement. I'm a total noob in Pixinsight...



M31 - Andromeda Galaxy

How do I get from where I am to an image which is just fantastic like:

https://www.astrobin.com/6938qg/?q=&camera=

Can my camera even do this (minus the red h-alpha) or am I doing good with what I have? Thanks again!

Benjamin
dkamen avatar
dkamen avatar
Benjamin DeHaven:
Here is my latest attempt based on what I could do in Photoshop with the Pixinsight advice which I couldn't figure out how to implement. I'm a total noob in Pixinsight...



M31 - Andromeda Galaxy

How do I get from where I am to an image which is just fantastic like:

https://www.astrobin.com/6938qg/?q=&camera=

Can my camera even do this (minus the red h-alpha) or am I doing good with what I have? Thanks again!

Benjamin

That image is done with a ten inch f/4 telescope, you simply cannot capture the same stuff with a 500mm lens at f/5.6. Regardless of camera used.

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