Color Criticality:

Although this looks like a galactic collision- this is actually more of a tango. The large spiral, NGC 2207, is passing in front of IC 2163. You can clearly see the disk and arms in front of the interloper. In terms of processing, this fact is actually an important consideration. The attenuation of starlight has a particular color bias- a reddening- that in this case makes IC 2163 look a little odd. If this was a galaxy like say NGC 6946 (as a good example) that was entirely reddened by intervening dust- then you get to choose to correct that or not for the entire object.

However, here there is a relative color distinction that itself is a feature of the object and so I argue it is important to consider/maintain. Although you could selectively adjust the color for the two galaxies independently…but this wouldn’t be playing the game in my philosophy.

Processing:

I did not do anything special in terms of my processing here other than one important step. This is a very bright object in sense that most of it is nearly the same brightness. They bluish arms and HII regions simply fluoresce with intense energy. I decided not to go for a dark brooding take on this…I went ahead and let the luminance blast a bit. However, this is where I made an important choice. It is all to easy to let the bright parts of the galaxy (especially the blue star associations and OB stars) become so bright that there is color loss. This is a real information that simply evaporates. My answer to this is quite simply to not let the luminance come in at 100%. This is in addition to the processing steps I took as described in my previous image of NGC 2996 with HDRMT and the like. This is my favorite way to manage the brightness of pixels where the object is too bright to color otherwise. It is clear to me the necessity of these actions just by looking the initial masterlights.

There is no rule that says the luminance has to be 100% and you are not losing detail or anything like that since we no longer bin for the color data. The color data might have less S/N than the luminance- but remember this is a bright-object-issue. Thus this choice doesn’t really have a big downside.

DIQ

Unfortunately my data is actually somewhat degraded. Currently I am operating with optics that will never fully take advantage of the seeing/skies due to optical aberrations. I am hoping to fix this if I can. I took this data roughly at the same time my friends Mark McCominskey and John Hayes did. (See John’s image of this same object with his equipment. (https://app.astrobin.com/i/fdj9k7?r=I) ) These guys have subarcsecond data. My resolution is nearly twice theirs at the moment. In addition, the direct drive of the mount is not tuned equally well for all positions of the sky- so resonance vibrations are common and affect the DIQ.

Let me show you… holy oscillations batman!

📷 Screenshot 2026-02-03 102822.jpg

That being said, I hope the takeaway here is the balance between brightness, color, contrast, and detail. These levers are so tempting to pull down to their maximum. But each is at the expense of the other. For me this is akin to finding just the right shape and mass rocks to balance on each other… and then step back slowly and enjoy the curious pseudo-stable creation.

I include the full field as well as the cropped version of this image.