Constellations are large groups of
stars that are clustered to form imaginary
patterns. "Constellations can be a useful way to help identify positions of stars in the sky. Constellations have imaginary boundaries formed by "connecting the dots," and all the stars within those boundaries are labeled with the name of that constellation" ("StarChild Question").
Even though stars appear to be very close together
from the earth, they are often vast distances apart ("StarChild Question").
"Over half of the 88 constellations the IAU recognizes today are attributed to ancient Greek, which consolidated the earlier works by the ancient Babylonian, Egyptian and Assyrian. Forty eight of the constellations we know were recorded in the seventh and eighth books of Claudius Ptolemy’s Almagest, although the exact origin of these constellations still remains uncertain. Ptolemy’s descriptions are probably strongly influenced by the work of Eudoxus of Knidos in around 350 BC. Between the 16th and 17th century AD, European astronomers, and celestial cartographers added new constellations to the 48 previously described by Ptolemy; these new constellations were mainly “new discoveries” made by the Europeans who first explored the southern hemisphere" ("Origin of Constellations").