Argelander, Friedrich Wilhelm August, a celebrated astronomer, born at Memel in 1799. He superintended the observatory at Abo, Finland, from 1823 to 1828, when it was burnt down, and he erected another at Helsingfors. In 1837 he was appointed professor of astronomy at Bonn, and died in 1875. He published a celestial atlas, and fixed the position of 22,000 stars. His later years were devoted to observing the varying brilliancy and magnitude of the stars, and to proving that the entire solar system is moving through space.