Photograph taken at the Mount Wilson Observatory, in Pasadena, California. From left to right Dr .Walter Adams, (Director of the observatory), Sir James Jeans and Dr. Edwin Hubble. Circa 1903's. Walter Sydney Adams, (1876-1956) American astronomer. His primary interest was the study of stellar spectra. He worked on solar spectroscopy and co-discovered a relationship between the relative intensities of certain spectral lines and the absolute magnitude of a star. James Hopwood Jeans (1877-1946) was an English physicist, astronomer and mathematician. He made important contributions in many areas of physics, including quantum theory, the theory of radiation and stellar evolution. Jeans, along with Arthur Eddington, is a founder of British cosmology. Edwin Powell Hubble (1889-1953) was an American astronomer who profoundly changed the understanding of the universe by confirming the existence of galaxies other than our own, the Milky Way.