What does "the ecliptic and the underworld" mean in ancient astronomy?

The ecliptic refers to the sun's orbit around the stars for one year, and the underworld refers to the moon's orbit around the stars. The ecliptic and the underworld were originally used by ancient astronomers to observe the trajectory of the sun and the moon centered on the sphere, and were later attached by astrologers with various theories such as good luck and bad luck.

Astrologers match 12 earthly branches of the sun with 12 different gods. In these twelve days, the twelve gods each rotated once and went back and forth.

Zi Ri Qinglong, Chen Kui, Shen Ri Tianjian, Ugly Ri, Si Ri Tiande, You Ri Xuanwu, Yin Ri Tian Xing, Wu Bai Hu, Xu Ri Siming, Mao Ri Suzaku, Wei Ri Yutang, Gou Chen.

The auspicious days of the ecliptic include the days when Qinglong, Tang Ming, Jingui, Tiande, Yutang and Siming Six Gods are valued.

Mafia auspicious days include days when we attach importance to Heaven, Suzaku, White Tiger, Heavenly Prison, Xuanwu and Gouchen Six Gods.

Song Yue:

The ecliptic is the most suitable for all kinds of actions:

The door is right and famous, and the children and grandchildren hang purple clothes from generation to generation.

Mafia fierce star creation, famine chaos will be alarmed;

In and out, extremely dangerous, once closed the field.

It is worth mentioning that the ecliptic day is not necessarily the best, and the underworld day is not necessarily the worst. It depends on the year of birth and blessings of other good and bad gods.