Black and white photograph of the 40 inch Yerkes Equatorial Telescope. The telescope was the largest of its kind in the world. It was designed, built and erected by Warner & Swasey, along with a 90 foot dome and 75 foot elevating floor. Telescope column and head rise to a height of 43 feet and weighs 50 tons. The tube is 64 feet long and 52 inches in diameter at the center. The total weight of the instrument is 75 tons. The 40-inch objective lens was made by Alvan Clark. The dedication of the observatory was not until October 1897. Its first director was Dr. George E. Hale.