M31 Andromeda Galaxy

UPDATE:
There have been so many changes in PixInsight after I posted this image - improvements/upgrades to existing tools, new tools - that I felt like there was an opportunity to improve this image of my first monochrome dataset for M31.  That being said, as my original description indicates below, there still exist some shortcomings with the original dataset that I hope to correct when M31 next comes around.

Also there have been some significant discoveries about M31 that indicate it needs long exposures in Ha and Oiii to reveal structures/detail that was not previously known.  This is not the only galaxy that is revealing new discoveries in narrow band imaging, contradicting established knowledge that galaxies are strictly broadband objects.  KJ

Setting that aside, I do believe I made some significant improvements to my first version from the original dataset.  I will leave the original image available for comparison, so please let me know what you think!

Update 2(ish):
The current/last update is a result of my efforts to get something useful out of my badly underexposed Ha frames.  I have as many in number as the LRGB, but with narrowband they needed much more exposure time to provide what I am looking for.  Plus while there is an Ha component to the M31, it is not as prevalent as the broadband data.  I pushed it about as hard as I think I can without creating other problems; some Ha highlights/points do make their presence known but not to a great extent.

I will remedy this during the coming summer when M31 is once again available and add to the existing dataset.  In planning for this, I think I have all the LRGB data that I need for this target, so that should allow me to focus on Ha and Oiii.  The discovery of significant Oiii structures within M31 just recently occurred, which is why you don't see that in M31 images to date.  I expect that will change rapidly in the coming years.

Let me know what you think and if you have any suggestions on how to blend the Oiii data into the LRGBHa dataset.
Thanks in advance,
Clayton
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Some learnings from this effort - the Ha needs much more exposure time than the RGB/L filters do if it is to capture more signal than noise.  Also, I found the mono images are less noisy than OSC frames with comparable exposure time.  Resolution/detail is significantly improved in the mono frames vs the OSC frames.(comparing ZWO ASI2600MM to ASI2600MC images).  The trade off is significantly more post processing times, a very different workflow in PixInsight (compared to OSC processing).  There are really two different post processing stages - processing the mono frames in preparation to combining them to create an RGB image.  The post processing to the combined mono channel image to achieve the desired/desirable end product.

In a direct comparison to my previous OSC images, the RGB in noticeably less noisy and has more fine detail as well as capturing a larger image dynamic range/fainter galaxy structure than the OSC images posted previously.  You can see/compare them directly your self from my Astrobin Gallery.

R = 69x180s images
G= 52x180s images
B=57x180s images.
L=70x120s images
Ha=55x180s images

Update:  I went back and incorporated the Ha and Lum data into this image of M31 in Version C and I also pulled the stars back quite a bit to make M31 more the center of interest in the image.  I felt that it was on the verge of being overwhelmed by the stars in the previous verions.

ref: https://en.wikipedia.org/wiki/Andromeda_Galaxy

The Andromeda Galaxy (IPA: /ænˈdrɒmɪdə/), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula (see below), is a barred spiral galaxy approximately 2.5 million light-years (770 kiloparsecs) from Earth and the nearest major galaxy to the Milky Way. The galaxy's name stems from the area of Earth's sky in which it appears, the constellation of Andromeda, which itself is named after the Ethiopian (or Phoenician) princess who was the wife of Perseus in Greek mythology.

The virial mass of the Andromeda Galaxy is of the same order of magnitude as that of the Milky Way, at 1 trillion solar masses (2.0×1042 kilograms). The mass of either galaxy is difficult to estimate with any accuracy, but it was long thought that the Andromeda Galaxy is more massive than the Milky Way by a margin of some 25% to 50%. This has been called into question by a 2018 study that cited a lower estimate on the mass of the Andromeda Galaxy, combined with preliminary reports on a 2019 study estimating a higher mass of the Milky Way.  The Andromeda Galaxy has a diameter of about 220,000 ly (67 kpc), making it the largest member of the Local Group in terms of extension, if not mass.[citation needed]

The number of stars contained in the Andromeda Galaxy is estimated at one trillion (1×1012), or roughly twice the number estimated for the Milky Way.

The Milky Way and Andromeda galaxies are expected to collide in around 4.5 billion years, merging to form a giant elliptical galaxy or a large lenticular galaxy. With an apparent magnitude of 3.4, the Andromeda Galaxy is among the brightest of the Messier objects, making it visible to the naked eye from Earth on moonless nights, even when viewed from areas with moderate light pollution.