Above is an amazingly clear Hubble image of the Andromeda Galaxy, a mere 2.5 million light years away.
NASA offers a startling analogy regarding this clarity:
The Hubble Space Telescope is powerful enough to resolve individual
stars in a 61,000-light-year-long stretch of the galaxy’s pancake-shaped
disk. It's like photographing a beach and resolving individual grains
of sand. And there are lots of stars in this sweeping view -- over 100
million, with some of them in thousands of star clusters seen embedded
in the disk...Because the galaxy is only 2.5 million light-years from Earth, it is a
much bigger target in the sky than the myriad galaxies Hubble routinely
photographs that are billions of light-years away. This means that the
Hubble survey is assembled together into a mosaic image using 7,398
exposures taken over 411 individual pointings.
Image credit: NASA, ESA, J. Dalcanton, B.F. Williams, and L.C. Johnson
(University of Washington), the PHAT team, and R. Gendler
