That surface is Arcadia and that lantern is their sun. Thus at the edges of the Faelands, the sun reaches the pinnacle of its upswing before falling back the way it came. The equilibrium position of the pendulum sun is near the centre of the Faelands, directly above the city of Pivot. There, it is almost never night, as the sun is always close enough to impart at least a hazy twilight of illumination.
