ALTAIR, the brightest star in the constellation Aquila (q.v.), and, on this account, also known as a Aquilae. It is the middle member of the group 0, a, y in the constellation, and is of the first magnitude, being one of the nearest stars. Its distance from the solar system is four parsecs or 14 light-years. (See LIGHT YEAR.) It is a globe giving out 12 times as much light as the sun.