Perkins Observatory were both growing. Light pollution therefore became increasingly problematic. So in 1961 the Perkins Telescope was moved to Lowell Observatory in Flagstaff, Arizona. Lowell is the largest private observatory (non-university or government affiliated) in the world. Through the end of the 20th century, the Perkins Telescope was the observatory’s largest instrument. Observing time on this instrument was shared between Lowell astronomers and the Ohio State University. The telescope at Perkins was immediately replaced with a cassegrain reflector telescope. It was donated by Michael R. Schottland, an entrepreneur from Martinsville, Virginia. At that time it was the largest privately owned telescope
Heidelberg-Königstuhl State Observatory in 1906. The observatory ceased to be run by the German federal government in 2005 when it was joined with the Institute of Theoretical Astrophysics and Astronomical Calculation Institute to make up the Center of Astronomy of the University of Heidelberg. Between 1912 and 1957 Karl Wilhelm Reinmuth discovered almost 400 asteroids from the Heidelberg-Königstuhl State Observatory. Heidelberg-Königstuhl State Observatory Heidelberg-Königstuhl State Observatory () is a historic astronomical observatory located near the summit of the Königstuhl hill in the city of Heidelberg in Germany. The predecessor of the current observatory was originally opened in 1774 in the nearby city of