This mosaic of M31 merges 330 individual images taken by the Ultraviolet/Optical Telescope aboard the Swift spacecraft. It is the highest-resolution image of the galaxy ever recorded in the ultraviolet. Also known as the Andromeda Galaxy, M31 is more than 220,000 light-years across and lies 2.5 million light-years away. On a clear, dark night, the galaxy is faintly visible as a misty patch to the naked eye.
The irregular shape of the image results when the more than 300 images were assembled to make the final image.
There are three instruments on Swift—a UV telescope, an X-ray telescope, and the Burst Alert Telescope which serves as the gamma ray burst detector for the spacecraft. I contributed to the design of the ultra-quiet regulators powering the detector blocks in the BAT.
Image Credit: NASA /Swift / Stefan Immler (GSFC) and Erin Grand (UMCP)