Americanastronomer. Working under S. Newcomb, he calculated an orbit for Phoebe, discovered in 1898. He designed and built the first photographic zenith tube, completed in 1911. He spent the years 1915–24 developing emulsions and lenses for astrophotography, including coma-correcting lenses for large reflectors. A photographic survey (1924–39) yielded the Ross Catalogue of 869 stars with large proper motion. He photographed Mars and Venus from Mount Wilson, discovering markings in Venus's clouds in the ultraviolet.
Subjects: Astronomy and Astrophysics.