W H Walter Baade. Portrait of Wilhelm Heinrich Walter Baade, American astronomer (1893-1960). Born in Germany, he worked at the Hamburg observatory before moving to the Mount Wilson observatory in California in 1931. He studied star groupings in various systems. He showed that spiral galaxies contained generally hot blue stars and elliptical galaxies mainly cooler red ones. Using a 100 inch telescope, he resolved the Andromeda galaxy (Earth's nearest major galaxy) into discrete stars. He also identified several cosmic radio sources optically, using the 200 inch Mount Palomar telescope. He received the Royal Astronomical Society's Gold Medal in 1954.