Constellations are determined by the date of the solar calendar. Lunar calendar1May 27, 998, the solar calendar date is June 2 1 day, and the constellation of that day is Gemini.
Lunar calendar: May 27th, the year of Wuyin.
Main branches: wuyin, wuyin and jihai.
Gregorian calendar: 1998 June 2 1 Sunday Gemini
Source: Hua.com.