Three Pure Ones
In Taoism, the Seven-Star Lamp "qi xing deng" 七星燈 is a seven-lamp oil lamp lit to represent the seven stars of the Northern Dipper. This lampstand is a requirement for all Taoist temples, never to be extinguished. In the first 9 days of the lunar 9th month festival, an oil lamp of nine connected lamps may also be lit to honour both the Northern Dipper and two other assistant stars (collectively known as the Nine Emperor Stars), sons of Dou Mu appointed by the Taoist Trinity (the Three Pure Ones) to hold the Books of Life and Death of humanity. The lamps represent the illumination of the 7 stars, and lighting them are believed to absolve sins while prolonging one's lifespan.