This is the original telescope in the Lick Observatory. It was built around 1890 and has two 36-inch glass lenses at the optical entry point (on the left). The telescope and the dome house both rotate 360-degrees to see anything an astronomer would like. The telescope in fact has a clock mechanism that slowly turns it through the night to keep the view pointing at the same spot in the sky.
(Click the image to view a larger version.)