This 2.5 metres wide sandstone relief is a planisphere - a map of the stars on a plane projection. In the centre, the constellations are shown. 36 spirits - one for each ten days in the Egyptian year - stand in a circle around the stars. On the outside, the four pillars of the sky are shown in the form of standing women, with pairs of kneeling falcon-headed gods between them, all holding up their arms to support the vault of heaven. The zodiac was originally sited on the ceiling of the pronaos of the chapel dedicated to Osiris in the Hathor temple at Dendera. The pronaos (or portico) was commissioned by the Roman emperor Tiberius, as an addition to the late Ptolemaic chapel.