Hugh, yes, I focused on one of the pointer stars initially, then re-framed the shot, then flipped the camera on its side, without refocusing, hence the middle looking softer than the edges, which is not what you would expect
I was mainly experimenting with exposure and ISO and not paying much attention to focus, so its not a good photo to demonstrate edge sharpness
and it did surprise me when I saw the 100% crops.
It shouldn't be too long before I try it out on a properly dark sky
