How are the twelve constellations defined?

The constellation is set in the western population, which is determined according to the date of birth of each person in the solar calendar. Aries: March 2 1 to April 19 Taurus: April 20 to May 20 Gemini: May 2 1 to June 2 1 Cancer: June 22 to July 22 Leo: July 23 to August 22 Virgo: August 23. 8+1October 24th to165438+1October 22nd Sagittarius (Sagittarius):165438+1October 23rd to 65438+February 28th 2/kloc.