Atmospheric Dispersion Correction in Post Processing

The Earth's atmosphere refracts light of different wavelengths to a different degree, depending on an object's altitude above the horizon, hence declination dependent. I.e., the Earth's atmosphere acts as a prism.

Consequently, objects at the zenith will not have this effect, since the light from that position are perpendicular to the Earth's surface (and atmosphere) at that point.

The first image on the left shows the effect of atmospheric dispersion by the lower edge displaying a red tinge and the upper edge a bluish tinge.

The next 3 images show the individual frames after separating the channels using Michael Unsold's venerable ImagesPlus ( http://www.mlunsold.com/ ).

The last image on the first row is a GIF (click on original size) showing the vertical displacement between the individual RGB frames.

Next is the result of aligning then recombining the individual frames, again, with ImagesPlus.
And finally a side-by-side comparison, before and after the entire process.

With compliments to Mike.