Can the constellation be calculated by the lunar calendar?

Constellations are calculated according to the solar calendar. In fact, the constellation is for reference only, and it can't be accurate for everyone. Just have fun, don't take it too seriously.

Because the constellation is not 100% accurate. Your personality happens to be more like a balance. It may also be that your birthday is just at the junction of two constellations, so it is also a bit of Libra.