Stuart here is the same data at the native resolution. I did not bother about the vignetting it was more an exercise in potential resolution. I just wanted to show the whole of Crux without resorting to gradienxterminator. The FOV is 7x4.7 degrees. The actual focal length of a Canon 300mm F2.8L is 291 mm. Dithering does work as it is equivalent to drizzling. It is all about the Niquist Theorem and the method of sampling not just the sample interval. Fourier also comes to mind.
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http://d1355990.i49.quadrahosting.com.au/cruxnat.jpg
As we all have square pixels I would assume that ultimately at 700% things would look a bit blocky. It sure beats a 200k jpg. Or an image taken with the Hubble presented at a few hundred kilopixels.
Not all of us record a handfull of stars and some tiny bit of esoteric nebulousity on our entire sensor. So we can have the luxury of giving each star lots of pixels. RegiStar tells me there are over 80k of stars on that image. Some would say noise. You be the Judge!
Bert