Here you see one of the landmark sites in outer space--the distant Cat's Eye Nebula, as photographed by the Hubble Space telescope (top) and by a ground-based camera at the Palomar Observatory in California. Scientists who took the Palomar image say it is the "sharpest" photo ever taken of space. Not everyone agrees with them--certainly not the scientists who run the Hubble telescope. Go here to read about the argument.
As regular followers of this blog know, I love all this imagery. So this battle between telescopes is fascinating to me. The Palomar people say they achieved clarity by using a technique called "lucky imaging." (That sounds suspiciously like the way I take pictures, though my luck isn't so good.) With lucky imaging, you take a whole bunch of pictures and use a computer to combine the sharpest parts of each into a final image. It's kind of equivalent to high dynamic range imaging, except that the scientists are trying to get sharpness, not a wide tonal range. Now, let me be clear about something: I find the Hubble shot to be far more pleasing, whether it's sharper or not.