Germanastronomer, born in modern Lithuania. From a study of the proper motions of several hundred stars he confirmed F. W. Herschel's calculated position of the Sun's apex. His main achievement, begun in 1852, was a survey of all stars down to 9th magnitude in the northern hemisphere. The resulting star atlas and catalogue were published in 1859–62 as the Bonner Durchmusterung. He subsequently initiated the first AGK catalogue. Argelander also introduced the subdivision of magnitudes into tenths, the step method for estimating stellar magnitudes, and the practice of assigning capital roman letters to variable stars.
Subjects: Astronomy and Astrophysics.