Constellations are determined by the date of the solar calendar. In 1987, the solar calendar date of June 1 day is July 26th, and the constellation of that day is Leo.
Lunar calendar: The Year of the Rabbit jumps to June 1st.
Main branches: Ding Mao, Ding Weibingzi
Gregorian calendar:1July 26th, 987, Leo.
Source: Hua Wang.