Constellations are determined by the date of the solar calendar. Lunar calendar1April 29, 992, the Gregorian calendar date is May 3 1, and the constellation of that day is Gemini.
Lunar calendar: April 29th, 92.
Main branch: Renshen Yisi Ding Wei
Gregorian calendar:1May 3, 9921day Gemini
Source: Hua.com.