Why is there no 100 constellation?

Because as of February 26, 2022, there were only 88 confirmed constellations.

There are 88 constellations in the whole day. The standard number of constellations was formulated by the International Astronomical Union in 1930, and it has been up to now.

Constellation refers to one of the indispensable components of astrology, and also refers to the combination of stars in the sky. Since ancient times, humans have associated the three or five stars with their mythical figures or artifacts, which are called constellations.