Here's a picture of Hearthside. Most of their power comes from solar as you might expect. The City of Eternal Noon is located at the substellar point. The Eternal Hearth is the chief lighthouse for all of the Bright Way. In stead of a star hearth, the sanctuary is located under an oculus that lets in the light from Focus overhead. The light shines on a large mirror, symbolically making Focus itself the star hearth for the lighthouse.