步罡踏斗

bù gāng tà dǒu

to worship the astral deities (idiom, refers to Daoist astrology)

a step

gāng

stars of the Big Dipper that constitute the tail of the dipper

to tread

dǒu

abbr. for the Big Dipper constellation 北斗星[Bei3 dou3 xing1]