In 1880 he was awarded his Ph.D. from Humboldt-Universität of Berlin with a dissertation titled, Über den Einfluss von Luftdruck und Wärme auf die Pendelbewegung (On the influence of air pressure and heat on the movement of a pendulum).
In 1881 he joined the Astrophysical Observatory Potsdam (AOP) as an assistant, and would remain there until he retired.
His early career was spent on solar studies, including observations of sunspots and derivations of the rotation period.
He became an observer at the AOP in 1898, and the following year he collaborated with Julius Scheiner in an unsuccessful attempt to measure the radio emission from the Sun.
He performed extensive work on the luminosity, colors, and diameters of stars.