What are the symbols 13 and 15?

Constellations are divided according to the birthdays of the Gregorian calendar (new calendar, Gregorian calendar). When is the birthday of Gregorian calendar?

Aries (03/2 1-04/20)

Taurus (04/2 1-05/20)

Gemini

Cancer (22 June 2006-22 July 2007)

Leo (07/23-08/22)

Virgo (08/23-09/22)

Libra (09/23- 10/23)

Scorpio (10/24-11/22)

Sagittarius (11/23-12/21)

Capricorn (12/22-0119)

Water bottle: 0 1/ 20- 02/ 18

Pisces (02/ 19- 03/20)