"Dr. Haug, in his introduction to the Aitareya Brahman, has observed that: "The sattras (sacrificial sessions), which lasted for one year, were nothing but an imitation of the Sun's yearly course. They were divided into two distinct parts, each consisting of six months of thirty days each. In the midst of both was the Vishuvat, i.e. the equator or central day, cutting the whole sattra into two halves.""