Gaia scanning the sky

A visualisation of how Gaia scanned the sky during its first 14 months of operations, between July 2014 and September 2015. The oval represents a projection of the celestial sphere, with different portions of the sky gradually appearing, according to when and how frequently they were scanned by Gaia. The satellite scans great circles on the sky, with each scan lasting about 6 hours. During the first month, the scanning procedure was such that the ecliptic poles were always included. This meant that Gaia ob