M32 & M42, up to two hours stacked

So here is the same shot as in the previous post, with another hour added to the stack. Since it needs to be stretched less to achieve similar brightness, there is less "stress" visible in the image; the background is beginning to become an even black, etc. I expect this to take a total of 5 hours in the final stack to really work well, but I want to post the individual steps along the way. It takes 3-4 hours of shooting get 1 hour's worth of usable subs.

While most photographers would try and get a ten minute exposure to bring out the lower half of the nebula (which is FAR fainter than the upper half, I have found that my method of dealing with light pollution (which essentially limits my exposures to 30 seconds) is turning out to be a way to show bright nebula with the dynamic range adjusted. A normal photograph that brought out this much of the lower "jaw" of the fish's mouth would have the area at the top around the Trapezium totally blown out. One I complete this photo after another 3 nights of shooting, I should be able to not only capture the fainter regions, but still show detail in the very bright regions, and probably still resolve the Trapezium in the center of the brightest areas. The downside is that it does take many nights, and many hundreds of individual photographs, aligned of several nights of work. I've started calling the process "speckle stacking", since it really is a weird variation on the "speckle imaging" used by modern giant telescopes, but with exposure in the seconds, not milliseconds. It's a very low-tech way to take advantage of the pro's high-tech method.

I have an idea what may be causing the banding on the left and right images-I'll know after my next photo shoot if I am right.