George A. Van Biesbroeck was a Belgian–American astronomer. He worked at observatories in Belgium, Germany and the United States. He specialized in the observation of double stars, asteroids and comets. He is notable for his long career as an observational astronomer.
George Van Biesbroeck
Maximilian Franz Joseph Cornelius Wolf was a German astronomer and a pioneer in the field of astrophotography. He was the chairman of astronomy at the University of Heidelberg and director of the Heidelberg-Königstuhl State Observatory from 1902 until his death in 1932.
Max Wolf
The Bruce double astrograph at Heidelberg Observatory