I am1976,8, 12. What is the constellation?

First of all, constellations are calculated according to the solar calendar.

If you are talking about August in the solar calendar 12, it is Leo: July 23rd-August 22nd.

If you are talking about August 12 of the lunar calendar, it is September 5 when converted into the solar calendar. Virgo: August 23rd-September 22nd.

I hope my answer can help you.