I think you did a wonderful job with these images, so please do not take my questions as a criticism, I merely want to learn.
The stars in the center are perfect white dots. In the corners, the colors shift from blue toward the center and red towards the corners. What is the cause of this aberration and how is it corrected?
Second, how do you feel the resolution and color fidelity of this camera compare to a mono 4/3 like the ASI1600? If they are close enough that there is no discernible difference, then the workflow simplicity, time savings, weight savings would be tremendous. A $2000 ASI2600 is roughly $500 cheaper than an ASI1600 + filters + wheel.
I am not offended at all. That is a very good question and good catch and also how we all learn. Unfortunately, it is a well-know effect of the Celestron 0.7x focal reducer which has been well documented on CN and other astronomy forums. So, it has nothing to do with the camera and is next to impossible to process out other than crop the image until they are removed. That is also why many users of the Celestron SCTs avoid the reducer and use either a hyperstar (which I did for many years) or image with no reducer.
The 2600 is a fantastic OSC camera producing very low noise, no amp glow, and excellent color and resolution. I have owned several color cameras and it is hard to beat. I also now use the 533 which is essentially the baby brother of the 2600. I also own the mono 1600 and primarily use it for narrowband imaging and not RGB images. If you are comparing the color produced by the 1600 MM with LRGB filters to the OSC 2600, the 1600 almost always produces better color images and I believe most experts will tell you that as well. Arguments rage back and forth as to what approach to take based on costs, time involved, etc., but in my opinion, the gap between the newer OSC cameras like the 2600 and a mono camera like the 1600 with color filters is closing. Again, many would scream that is nonsense. I am very content with the newer OSC cameras and the mono cameras only for narrowband palette images. Based on cost, the 2600 plus a OSC narrowband filter like the L-enhance is all you need for great images of emission nebulae and no filter (or perhaps a light pollution filter) for galaxies. The cost goes up with the mono camera as you need a complete filter set and a filter wheel or a cheaper filter drawer. Workflow and time involved is slightly more with the mono approach as you need flats for each filter, etc but this can be as simple or as complicated as you want it to be. There is a learning curve you have to go through and remember there are other variables like your sky conditions.
My final suggestion is, if you have not already done so, is to go on sites like here and Astrobin and see images taken with the 1600 and 2600 (or 533) before you decide. Both are great cameras so in the end, you win. It is a matter of personal preference as to what route you prefer to take. There is no wrong choice.
I hope this helps a little in making your decision.