Constellations are determined by the date of the solar calendar. 1June, 997, the Gregorian calendar date is1July, 6, and the constellation of that day is Cancer.
Lunar calendar:1June 997 12.
Main branch: Ding Chou Ding hasn't done his own thing.
Gregorian calendar:1July, 997 16 Wednesday Cancer
Source: Hua.com.