Steward Observatory history, and today it is telling us facts, forever wonderful, about the size of our universe; perhaps tomorrow it will give us practical help in showing us how to predict climatic conditions in the future. Steward Observatory manages three different observing locations in southern Arizona: Mount Graham International Observatory (MGIO), Mount Lemmon Observatory, and Catalina Station on Mount Bigelow. It also operates telescopes at two additional important observatories: Kitt Peak National Observatory (KPNO) and Fred Lawrence Whipple Observatory on Mount Hopkins. Steward is a partner in the Sloan Digital Sky Survey-III, which is located in New Mexico at Apache Point
Percival Lowell Planet X. Lowell started a search program in 1906 using a camera in aperture. The small field of view of the reflecting telescope rendered the instrument impractical for searching. From 1914 to 1916, a telescope on loan from Sproul Observatory was used to search for Planet X. Lowell did not discover Pluto but later Lowell Observatory (observatory code 690) would photograph Pluto in March and April 1915, without realizing at the time that it was not a star. In 1930 Clyde Tombaugh, working at the Lowell Observatory, discovered Pluto near the location expected for Planet X. Partly in recognition of