1781 van Biesbroeck (A906 UB) is a main-belt asteroid discovered on October 17, 1906 by A. Kopff at Heidelberg.
Georges-Achille van Biesbroeck (January 21, 1880 – February 23, 1974) 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.