According to Cedric Cummins’ The University of South Dakota 1862-1966:
Meanwhile, lesser structures and changes were in process. Dr. Thomas E. McKinney, Chairman of the mathematics department, had worked for an observatory since his arrival in 1907. He won support, and business secretary J. H. Julian reported a balance of $13,636.23 from local and endowment funds for the year ending June 30, 1916, “to build a coal house and astronomical laboratory.” The first was constructed back of University hall near the water plant. Work was begun on the brick observatory that fall, north of the athletic field, and completed in 1917 at a cost of approximately $6,500. Its chief pride was the five-inch refractor telescope built in London by Thomas Cooke, Ltd., with a “weight-clock” making it possible to correlate its movement with the rotation of the earth. Another medium had been added by which the University sought to survey the universe from its small base.