The constellation is determined by the date of the solar calendar. Gregorian calendar 1990 The date of May 9th of the lunar calendar is 1 July, and the constellation of that day is Cancer.
Lunar calendar: the ninth day of May in Gengwu.
Main branch: Geng Wuren Wu Dingmao
Gregorian calendar: 1 July 9901Sun Cancer
Source: Hua.com.