OT:

Pleiades stack result:



The current stack (left) compared to an older version (right) of the same target:
Resolution of the left image is a bit higher (different camera).
Look at the increased sharpness and details due to the reducer/flattener/coma corrector. Don't mind the color difference, it's only based on editing.
Focal lengths are effectively identical (750mm), the left image is reduced 0.75x from 1000mm by the added optical corrector.