Astronomer. Born Cologne, Germany, 1806; died Munster, 1877. He taught mathematics and sciences in the gymnasium of Cologne (1827-1837), in the high school at Aix-la-Chapelle (1837-1852), and in the Academy (now University) of Munster (1852-1877). His treatises dealt with his observations of auroral light, sun-spots, comets, zodiacal light, etc. During the Kulturkampf he championed Catholicity. Founded the Journal of Astronomy, Meteorology and Geography. First ascertained the point of departure of meteors. Drew up a chart of naked-eye stars visible from Central Europe, which indicated 5,421 stars, included the first authentic map of the Milky Way, and has been used as a basis for other star charts. Made valuable observations of variable stars.