Betsila was a galaxy known to the Anschlasom. From the perspective of the Milky Way Galaxy, Betsila was relatively close to Shrask and lay beyond the Illiara and Oskria galaxies. Betsila was along the route to the distant Som. (VOY novel: The Eternal Tide)
Billions of years ago, Betsila was known to the Anschlasom. When a group of them passing through the Som stranded on the Mikhal Outpost 10,000 years ago, they carved their astronomical knowledge into stone and a cave. Betsila was depicted on an artifact, one in a series arranged in the Fibonacci sequence.
In August 2381, Federation Fleet Commander Afsarah Eden, Counselor Hugh Cambridge and the Doctor traveled to the Mikhal Outpost to investigate Eden's origin, which was linked to the Anschlasom. Looking on the artifacts, Eden remembered the names of Anschlasom constellations and galaxies. (VOY novel: The Eternal Tide)