A constellation in the northern sky sometimes called in English the Great Bear. Arthur was associated with it, perhaps from the fact that Welsh arth signifies a bear.
It is circumpolar, which means it can be seen throughout the year in the northern hemisphere, and its position in the night sky changes with the seasons. In the spring and early summer, it is high in the sky during the evening. In the fall and winter, it is lower on the horizon.
The English astronomer William Smyth (1788-1869) in his Speculum Hartwellianum suggests that the circular motion of the constellation may have been the origin of the idea of the Round Table.