Edwin P Hubble, who discovered the scale of the Universe.

http://antwrp.gsfc.nasa.gov/diamond_jubilee/hubble_nas.html

After World War II Hubble returned to his position at the Mount Wilson Observatory where his research, so brilliantly carried out between two world wars, had provided strong evidence of the need for a telescope larger than the 100-inch reflector. He had assisted greatly in the design of the 200-inch Hale telescope, and had served on the Mount Wilson Observatory Advisory Committee for building the Mount Palomar Observatory. "With the 200-inch," he said in a BBC broadcast in London," we may grasp what now we can scarcely brush with our fingertips." "What do you expect to find with the 200-inch?" he was asked, and he replied, "We hope to find something we hadn't expected."