Copenhagen | University of Copenhagen | Royal Observatory, Greenwich | observatory | Royal Observatory | Paris Observatory | Palomar Observatory | Battle of Copenhagen | Yerkes Observatory | Copenhagen City Hall | Arecibo Observatory | Siding Spring Observatory | Mount Wilson Observatory | F.C. Copenhagen | The Lakes, Copenhagen | Smithsonian Astrophysical Observatory | Observatory | Harvard College Observatory | University of Copenhagen Botanical Garden | Royal Copenhagen | Ondřejov Observatory | Lowell Observatory | Kew Observatory | Copenhagen Municipality | Copenhagen Business School | Roque de los Muchachos Observatory | Pulkovo Observatory | McDonald Observatory | Jodrell Bank Observatory | Chandra X-ray Observatory |
He became Professor of Astronomy and director of the Copenhagen Observatory of the University of Copenhagen in 1907.