Keywords: Yerkes Messier 51 Canum Venaticorum 1902.jpg en A photo of the galaxy Messier 51 taken on June 3 1902 1902-06-03 ASTRONOMICAL PHOTOGRAPHY WITH THE FORTY-INCH REFRACTOR AND THE TWO-FOOT REFLECTOR OF THE YERKES OBSERVATORY G W RITCHEY other versions PD-old-70-1923 Astronomy Yerkes Observatory Messier 52 |