The constellation is determined by the date of the solar calendar. On February 7th, 2007, the Gregorian calendar date is March 25th, and the constellation of that day is Aries.
Lunar calendar: the seventh day of February, o 7.
Main branch: Guimao Wuwu, Dinghai
Gregorian calendar: March 25th, 2007, Sunday, Aries.
Source: Hua.com.