constellation

One of 88 designated areas in the sky or the pattern of stars within it. Records show that, from antiquity, civilizations have given names to conspicuous patterns of bright stars. Each culture had its own way of dividing the sky into pictorial elements. Many of those in use today originated in Mesopotamia and were further developed by the Greeks. Ptolemy listed 48 in the second century AD and the rest have been added since about 1600. Some proposed constellations that have never found general acceptance appear on old star maps. Originally, constellations were regarded simply as star patterns, but they gradually acquired usefulness as a way of specifying stars and their positions. As the science of astronomy developed, the lack of precise standard definitions for the constellations led to confusion in identifying fainter stars in more sparsely populated regions of the sky. This was resolved when, in 1930, there was international agreement among astronomers to define the boundaries of 88 constellations along lines of right ascension and declination. Each of the 88 constellations has an entry in this Dictionary under its official Latin name; all the constellations are listed in Table 4.