How many constellations are there?
There are 88 constellations in modern international astronomy.
The history of constellations goes back thousands of years. It has been suggested that ancient cave paintings depict constellations from as early as 15,000 BCE. Plenty of examples of constellations appear from around 1,000 BCE. Ancient Greeks identified around 50 constellations, and these form the basis of the constellations used by astronomers today.
In 1928 the International Astronomical Union settled on the official list of 88 modern constellations. Although based on ancient constellations, the modern system divides the entire sky as seen from Earth into areas with boundaries, so every single part of the sky is part of a constellation.