Stunning photo mosaic of neighbouring Andromeda Galaxy captures the glow of 200 million stars

$This is the largest photomosaic ever assembled from Hubble Space Telescope observations. It is a panoramic view of the neighboring Andromeda galaxy, located 2.5 million light-years away. It took over 10 years to make this vast and colorful portrait of the galaxy, requiring over 600 Hubble overlapping snapshots that were challenging to stitch together. The galaxy is so close to us, that in angular size it is six times the apparent diameter of the full Moon, and can be seen with the unaided eye. For Hubble's pinpoint view, that's a lot of celestial real estate to cover. This stunning, colorful mosaic captures the glow of 200 million stars. That's still a fraction of Andromeda's population. And the stars are spread across about 2.5 billion pixels. The detailed look at the resolved stars will help astronomers piece together the galaxy's past history that includes mergers with smaller satellite galaxies.$

To celebrate the 100-year Edwin Hubble discovery that Andromeda was a galaxy outside our own, astronomers release the most detailed Andromeda Galaxy image ever.