built by Alvan Clark & Sons in 1929. In 1930 it was used by Clyde Tombaugh to discover Pluto. In 1971, it was moved a new building at Anderson Mesa, and returned to Mars Hill in 1992. See also United States Naval Observatory Flagstaff Station List of astronomical observatories References External links Lowell Observatory website Anderson Mesa Station Clear sky clock Weather forecasts for observing conditions. Astronomical observatories in Arizona Buildings and structures in Coconino County, Arizona 1959 establishments in Arizona