Is auspicious day an idiom?

This is an idiom. Huáng dào jí rì is a day for everything. In the past, astrology was used to calculate good or bad luck. It is said that Qinglong, Tang Ming, Jingui, Tiande, Yutang and Siming are auspicious gods. When they were on duty on the sixth day, everything was all right, and they didn't avoid bad luck. This day was called "auspicious day of the ecliptic". Generally refers to a good day to do things. From the fourth fold of Yuan Anonymous's Chain Plan: "Today is an auspicious day for Emperor Daoism, and the ministers of Manchu Dynasty are all at Yintai Gate, urging the Grand Master to enter the court and meditate." Farmers' calendars or yellow calendars and children can choose auspicious days, such as marriage, marriage, engagement, dating, opening, opening and moving. The so-called yellow mafia is a natural phenomenon in celestial bodies. The predecessors summarized the law of this phenomenon's influence on human beings, and formulated "Yellow Mafia Day" around the operation and responsibilities of the 28 stars. Therefore, it provides a certain reference and choice for human survival and development, seeking good fortune and avoiding evil.