NASA's Swift satellite has acquired the highest-resolution view of the neighboring spiral galaxy M31.
Also known as the Andromeda Galaxy, M31 is the largest and closest such galaxy to our own.
It's more than 220,000 light-years across and lies 2.5 million light-years away in the constellation Andromeda.
Between May 25 and July 26, 2008, Swift's Ultraviolet/Optical Telescope (UVOT) acquired 330 images of M31 at wavelengths of 192.8, 224.6, and 260 nanometers.
The images represent a total exposure time of 24 hours.
Some 20,000 ultraviolet sources are visible in the image, including M32, a small galaxy in orbit around M31.
Dense clusters of hot, young, blue stars sparkle in the disk beyond the galaxy's smooth, redder central bulge.
Star clusters are especially plentiful along a ring about 150,000 light-years across.