Harvard College Observatory, 1896, 17 April, Omega Centauri [photograph taken by Bruce telescope, April 17, 1896, exposed 30 minutes], Photographic print, Harvard University Archives, LL/41658
Harvard College Observatory, 1896-1899 (ca), [Bruce Telescope at Harvard College Observatory, Southern Station, Arequipa, Peru, Cyanotype, Harvard University Archives, LL/41657