Source: Wikipedia

The Birth of Re Ceiling of the Purification Chapel (Wabet) Temple of Hathor, Dendera (plan)

The rays of the sun illuminate Hathor, the daytime sky, in this stunning relief. Nut, the night sky, arches around the sides and top of the photo. The Egyptians believed that the sun was swallowed by Nut at dusk, passed through her body unseen during the night, and was reborn from her body at dawn. The relief shows Nut swallowing Re during the night (starry background, upper right); the Milky Way flowing as a literal river of milk from Nut's breast (upper middle); and the reborn sun (upper left) illuminating Hathor (lower middle). Hathor's emblem rests upon the hieroglyph for "horizon," and is flanked by two growing trees as if to emphasize the life-giving properties of the sun.

The Birth of Re was especially commemorated on the first morning of every New Year, as mentioned on the previous page.