Herschel's Great Telescope, artwork. Also known as Herschel's 40-foot telescope, it was designed by William Herschel (1738-1822), one of the foremost astronomers of his time. The first observations with this telescope were carried out on 28 August 1789. The movement of the telescope (needed to track an object across the night sky) was carried out by an assistant in the hut (lower right). The assistant would use the system of wheels, ropes, pulleys, levers, and scaffolding to move the wooden telescope. Modern telescopes use computers to make these complex adjustments. Herschel (centre left) would make his observations by standing at the front of the telescope and looking down the tube at the mirror, which was made of polished metal, instead of glass. Artwork from Pioneers of Science (Oliver Lodge, 1893).