What is the constellation on April 3rd?

The constellation is looking at the solar calendar. The solar calendar corresponding to the third day of the fourth lunar month in the year when you were born is your constellation.

Libra 1/2 1 ~ 2/ 18 Leo July 23rd to August 23rd.

Pisces 2/ 19 ~ 3/20 Virgo 8/24 ~ 9/22

Aries 3/2 1 ~ 4/20 Libra 9/23 ~ 10/23

Taurus 4/2 1 ~ 5/2 1 Scorpio10/24 ~1/22.

Gemini 5/22 ~ 6/2 1 Sagittarius11/23 ~121

Cancer Capricorn 12/22 ~ 1/20 may be Aries or Pisces from June 22nd to July 22nd.