Telescope facts

■ The telescope was built in 1911 by the John A. Brashear Company in Pittsburgh.

■ The telescope saw first light at the Sproul Observatory at Swarthmore College.

■ The lenses are held in place by a brass ring.

■ The telescope has as 24inch diameter.

■ The refractor has been heavily used in astronomical photography: 100,000 by 1974.