1.Heavenly bodies like the stars, sun and moon are mentioned in the Avesta and also in Pahlavi books like Bundahishna and Zadsparam. The Pahlavi literature also mention constellations and planets.
2. In the Zoroastrian calendar, the 13th roj and the 4th māh are dedicated to Teshtar Tir or Tishtrya who is the leader among all stars. In Avestan times, Tishtrya was recognized as the brightest star in the Eastern sky and was given the position of “leader of all the stars.” It is identified with the star Sirius in the constellation of Canis Major. It’s rising coincided with the arrival of rains and hence it was considered the bringer of rains.
3. Whenever Tishtrya is remembered, the stars of the other three directions, who are his associates, are also remembered. In all, these 4 stars are the guardians of the four directions: Tishtriya (Sirius) of the East, Satavaesa (Anatares) of the South, Haptoiring (Great Bear) of the North, and Vanant (Wega) of the West. These are not only names of stars, but also names of Yazads who preside over the stars.
4. Vanant Yazad is identified with Wega, the brightest star in the constellation Lyra in the west. Vanant Yazad helps to overcome negative thoughts and protects against evil practices. He helps against moral and mental evil of all kinds like black magic, chants, sorcery and charms. He is victorious over evils and noxious creatures like rats, cats, snakes and wolves.
5. Haptoiring is identified with the Ursa Major or Great Bear constellation, which has seven main bright stars. The word Haptoiring means “having seven points”. It appears in the Northern sky. It is health and khoreh (energy) giving and helps keep away black magicians and sorcerors. It especially opposes Kewan (Saturn) and negates its ill effects.
6. Satavaesa is identified with the star Anatares in the South. In the Avesta it is further described as bright and having water content. Satavaesa as a Yazad is not invoked individually, but is always remembered along with Tishtrya.