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
William Lowell Putnam become trustee. After Gus's death, William's second son, Roger, became trustee. In 1927, Elizabeth Lowell Putnam established the William Lowell Putnam Intercollegiate Memorial Fund in order to begin a college-level mathematics competition, the William Lowell Putnam Mathematical Competition. This contest, which continues to this day, began in 1935 under the direction of the Mathematical Association of America. Putnam's grandson by the same name, William Lowell Putnam, born 1924, was a geologist, businessman, and climber, and served as the sole trustee of Lowell observatory from 1987-2013. William Lowell Putnam William Lowell Putnam II (November 22, 1861 – June 1923) (more commonly