Astronomer Percival Lowell established this facility in 1894, 1mi west of downtown Flagstaff. Here in 1930, Clyde Tombaugh discovered the tiny outer planet (since stripped of its planet-status) Pluto by photographing sections of the night sky at six-day intervals and looking for movements in the minuscule dots of light. Stars don't change position; the tiny point of light that did was identified as a planet. Lowell's own 24in Clark refracting telescope is on display and in use during frequent nighttime sky-viewing sessions. Interactive exhibits focus on basic astronomy and space travel.