[avandonk]

It is a waste of time comparing narrow field stacked images as used for planetary imaging to any optic that gives a high resolution flat wide field. Any decent optic is almost perfect (diffraction limited) at the optic axis. The real test is how wide a field can the optic produce with the same quality at the extremes of the field compared to the optic axis ie center.

A good example is the planetary blokes who image at f/40 and higher. The theoretical Airy disc at f/40 is about 60 micron. The reason they get high resolution is that they are only recording the tip of the central maximum of the Airy disk obove the noise as the contrast is very low and the dynamic range is also low. Their resolution is even better than the Dawes limit. The intensity of the Airy disk is not constant see image below.

At best an interesting observation.

Bert